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Age related changes in auditory processes in children aged 6 to 10 years
Accepted Manuscript Title: Age Related Changes in Auditory Processes in Children Aged 6 to 10 years Author: Asha Yathiraj C.S. Vanaja PII: DOI: Reference:
S0165-5876(15)00238-4 http://dx.doi.org/doi:10.1016/j.ijporl.2015.05.018 PEDOT 7594
To appear in:
International Journal of Pediatric Otorhinolaryngology
Received date: Revised date: Accepted date:
21-2-2015 13-5-2015 16-5-2015
Please cite this article as: A. Yathiraj, C.S. Vanaja, Age Related Changes in Auditory Processes in Children Aged 6 to 10 years, International Journal of Pediatric Otorhinolaryngology (2015), http://dx.doi.org/10.1016/j.ijporl.2015.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Age Related Changes in Auditory Processes in Children Aged 6 to 10 years
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Asha Yathiraj1 and C S Vanaja2
Professor of Audiology
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Email: [email protected]
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All India Institute of Speech and Hearing, Mysore, India
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Professor of Audiology,
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School of Audiology & Speech language pathology
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Bharati Vidyapeeth Deemed University, Pune, India
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Email: [email protected]
Corresponding author: C S Vanaja
Professor of Audiology Bharati Vidyapeeth Deemed University School of Audiology & Speech Language Pathology, Pune, Maharashtra - 411043, India Email: [email protected] 1 Page 1 of 43
Age Related Changes in Auditory Processes in Children Aged 6 to 10 years
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Asha Yathiraj1 and Vanaja Chitnahalli Shankarnarayan2
Professor of Audiology
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Email: [email protected]
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All India Institute of Speech and Hearing, Mysore, India
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Professor of Audiology,
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School of Audiology & Speech language pathology
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Bharati Vidyapeeth Deemed University, Pune, India
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Email: [email protected]
Corresponding author: C S Vanaja
Professor of Audiology Bharati Vidyapeeth Deemed University School of Audiology & Speech Language Pathology, Pune, Maharashtra - 411043, India Email: [email protected] 3 Page 2 of 43
Abstract Objectives:
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The study evaluated age related changes in auditory processing (separation / auditory closure, binaural auditory integration abilities, temporal processing abilities) and higher order
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cognitive function (auditory memory & sequencing abilities) in children. Additionally, the study aimed to assess the effect of gender on the auditory processes / higher cognitive
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function as well as ear effect for the monaural tests that were administered.
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Methods:
The cross-sectional experimental study evaluated 280 typically developing children
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aged 6 to 10 years, divided into five age groups. They were evaluated on auditory processes / higher order cognitive functions reported to be frequently affected in children with auditory
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processing disorders (Speech-in-Noise Test in Indian-English, Dichotic consonant-vowel test,
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Results:
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Duration pattern test, & Revised Auditory Memory and Sequencing Test in Indian-English).
ANOVA and MANOVA revealed no significant gender effect in all four tests.
However, a significant age effect was seen, with the rate at which maturation occurred, varying across the tests. Conclusions:
Thus, the findings indicate that different auditory processes have different rates of development. This reflects that the areas responsible for different auditory processes / higher cognitive function do not develop at the same pace. Key words: Separation, integration, temporal processing, auditory memory 4 Page 3 of 43
Introduction Auditory processing is a complex phenomenon and consists of many processes that include auditory closure or separation, binaural integration, and temporal processing. Studies
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have indicated that children with auditory processing deficits frequently have difficulties in auditory separation or closure [1-3], binaural integration [1, 2, 4], and temporal processing [2,
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4]. Additionally, auditory memory, a higher order cognitive function has also been found to
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be frequently affected in them [2].
Age related changes of these processes or cognitive function in normal children have
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been used to determine their development. Furthermore, such age related changes have been used in the identification and management of children with auditory processing disorders.
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These age related changes can be attributed to the maturation of the brain. It has been substantiated that the cortical system is immature in children and continues to develop in
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adolescents [5-7]. Past research also indicates that different auditory processes do not mature
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in a similar manner but take different maturational courses [8-13]. A possible reason for the
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difference in maturation could be on account of the different cortical or brainstem areas that control them.
Perception of speech in noise, an auditory separation or closure process, involves
perception of spectro-temporal cues to identify the signal as well as ability separate signal from the background noise. Perception of speech in the presence of noise has been observed to result in reduced activity of the left hemisphere along with increased activity in the right hemisphere [14]. It has also been observed that noise entwined with speech results in a neural delay that makes it difficult to segregate the two at the brainstem and cortex [15]. Earlier, Efron, Crandall, Koss, Divenyi, and Yund [16] implied that the anterior temporal lobe was
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responsible for perception of speech in the presence of noise since individuals with lesions in this region exhibited difficulty in the task. Duration pattern test, a test for assessing temporal processing, requires discrimination
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of duration, perception of patterns or sequence as well as the ability to indicate the pattern heard. Functioning of both the hemispheres as well as the corpus callosum is required for Auditory integration, as assessed by dichotic
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giving verbal response on this test [17, 18].
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stimuli, involves the presentation of two different stimuli to the two ears simultaneously, both of which have to be identified by the listener. Dichotic tests are known to assess laterality,
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specialization of the auditory cortex in addition to the functioning of the two hemispheres and corpus callosum [19]. Likewise, auditory memory is reported to depend on the functioning of
[20].
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the hippocampus and amygdala that are located in the anterior temporal region of the brain The changes with age, in the areas responsible for the development of different
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auditory processes, may find a parallel with the behavioral development of the same.
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Auditory processes have been reported to start developing after birth and continue to
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develop as the child grows older, in line with the development of the central auditory nervous system. Keith [9] noted that those aged 12 to 50 years performed similarly on the six subtests (2 filtered words subtests, 2 auditory figure-ground subtests, a competing words & a competing sentences subtest) of SCAN-A.
It can be construed from these findings that
auditory closure or separation matures by 12 years of age. Further, Keith in 2000 reported the mean raw score of SCAN-C increased and the standard deviations decreased with increasing age in children aged 5 years to 11 years and 11 months. This variation in performance with increase in age was considered to reflect the maturation of the central auditory nervous system. Keith [9, 10] did not report whether the variation in performance across the ages was statistically significant or not. However, an investigation by Amos and Humes [8] did demonstrate the presence of a statistically significant difference in SCAN 6 Page 5 of 43
scores in children aged 6 and 9 years (first graders & third graders). Thus, these findings substantiate the presence of maturational changes in an auditory closure or separation task. A review of literature indicates that variation in scores across ages depends not only
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on the process evaluated, but also on the type of material used while evaluating a particular process. For example, Neijenhuis et al. [11] found no significant difference in a word-in-
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noise test scores obtained by adolescents (aged 14-16 years) and by adults whereas they
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observed a significant difference between the two age groups for a sentence-in-noise test. Thus, depending on the type of stimuli used, maturation of auditory closure or separation task
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varied. Similar to the word-in-noise test performance, Neijenhuis et al. [11] reported of no significant difference between adolescents and adults on a dichotic digit test. Additionally,
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they also noticed that in children aged 6 to 16 years there was no age effect for a frequency pattern test. However, they reported of an age effect on seven other tests carried out in this
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age group (words-in noise, filtered speech, binaural fusion, dichotic digits, duration patterns,
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backward masking, digit span). Based on their findings they concluded that maturation
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continues to develop even in adolescents.
Similar to the findings of research on auditory closure or separation, the procedure
and stimuli has been found to affect the results of tests for temporal processing. Lister, Roberts, and Lister [21] observed that performance of 11 to 12 year old children was similar to that of adults on a gap detection test whereas the performance of the 7 to 8 year and 8 to 9 year old children were poorer that of adults. They reported that the developmental effects observed by them were greater than most of those reported previously. Lister et al. [21] attributed this difference to variations in stimuli and procedure used. Maturational effects up to 12 years have also been documented by Stollman, Velzen, et al. [13], based on the findings of a longitudinal study of 20 children aged 6 years through
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7, 8, 10 and 12 years. This was seen for 9 tests (filtered speech test, binaural fusion test, frequency pattern test, duration pattern test, auditory word discrimination test, an auditory synthesis test, an auditory closure test, & a number recall test), but not for a speech-in-noise
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test. They noticed that in all ages, the children performed significantly poorer than their adult group, indicating that the processes evaluated continued to develop even after 12 years of
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age. Their findings substantiate the findings of Neijenhuis et al. [11] who also observed that
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maturation continued through adolescence.
Due to the large variability in results, it has been recommended that tests used for the
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evaluation of auditory processing should not be administered on children below the age of 7 years [22]. However, Stollman, Neijenhuis et al. [12] demonstrated that auditory processing
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tests that evaluated sustained auditory attention, binaural hearing, temporal processing, and phonological coding could be carried out effectively in children aged 4 to 6 years of age.
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Although no gender difference was observed, the older children were found to perform better
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than the younger children on the battery of tests. The difference was most prominent for the
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dichotic word test and the phoneme awareness test. From the review of literature, it is evident that there exist considerable variations
regarding the age related changes of the different auditory processes.
This has been
attributed to different auditory processes requiring different levels of functioning in the auditory system. There is a need for additional information in the area of age related changes in auditory processing to substantiate the developmental pattern seen in different auditory processes. Thus, the current study was carried out with the aim to determine age related changes in the performance of children on tests assessing different auditory processes or higher cognitive abilities (auditory closure or separation, temporal patterning, binaural integration, & auditory memory and sequencing). Additionally, the study aimed to evaluate
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the effect of gender as well as the performance across the two ears for the auditory processes or higher cognitive abilities.
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Methods Using a cross-sectional experimental design, age related changes on a battery of
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auditory processing tests were evaluated on 280 normal hearing children who were divided into five age groups. The battery consisted of four different tests that tapped different
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auditory processes or cognitive ability associated with auditory processing.
The tests
evaluated monaural auditory separation or closure, binaural auditory integration, temporal
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patterning, and auditory memory. These aspects of auditory processing were selected since they have been noted to be more frequently affected in children with auditory processing
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disorder.
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Participant selection
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The participants consisted of 280 school-going children (140 male & 140 female) in
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the age range of 6 to 10 years. The participants were recruited from two different centers in India having similar test facilities, one located in Mysore and the other in Pune. The participants tested in the two centers were matched in terms of gender and age. It was ensured that children were ‘not at-risk’ for auditory processing disorder, based on the ‘Screening Checklist for Auditory Processing’ developed by Yathiraj and Mascarenhas [23]. The children were categorized into five age groups (6 to 6;11 years, 7 to 7;11 years, 8
to 8;11 years, 9 to 9;11 years, & 10 to 10;11 years). The youngest age group had 40 children and the four remaining age groups had 60 children each. All the children had average or above average IQ on the Raven’s Progressive Colored or standard Matrices [24]. They attended schools where the instruction was in English and were reported by their teachers to
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be proficient in the language. Additionally, they were all reported to be right handed. Only those children with air conduction and bone conduction thresholds less than 15 dB HL in the octave frequencies 250 Hz to 8 kHz and 250 Hz to 4 kHz respectively, were included in the
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study. To confirm the presence of normal middle ear functioning, the participants were required to have 'A’ type tympanograms with ipsilateral and contralateral acoustic reflexes
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present for the frequencies 500 Hz, 1 kHz and 2 kHz. In addition, speech identification score in quiet was determined using the ‘Common Speech Discrimination Test for Indians [25], for
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all the participants. This test, with 25 nonsense consonant-vowels, had norms established on
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children. The test, presented through headphones at 40 dB SL, was utilized to confirm that the participants had normal speech identification scores in quiet. Only those with scores
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greater than 85% in quiet were included in the study. Additionally, the participants were required to have age appropriate language, which was assessed using on the Northwestern
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Syntax Screening Test developed by Lee [26].
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Equipment
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A calibrated dual channel diagnostic audiometer (OB 922 - Version 2) with air conduction (TDH-39) and bone conduction (B-71) transducers was used to carry out puretone audiometry, speech audiometry and the auditory processing tests.
The auditory
processing tests were played through a CD using a Compaq Presario 6000 laptop with Intel Pentium dual core processor.
To ensure normal middle ear functioning, a calibrated
immittance meter was utilized. Similar instruments were used in both centers where the data were collected.
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Test Environment All the audiological tests were carried out in a sound treated two-room suite with permissible noise limits as specified by ANSI standards [27]. The screening checklist, the IQ
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test and the language screening tests were administered in quiet, distraction-free rooms.
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Material
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The four auditory processing tests used to evaluate the children enrolled in the study included ‘Speech-in-Noise Test in Indian English’ (SPIN-IE) [28], ‘DCV’ [29], ‘DPT’ [18],
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and ‘Revised Auditory Memory and Sequencing Test in Indian-English’ (RAMST-IE) [30]. A sample of all the test material used for the study is given in Annexure 1. SPIN-IE and
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RAMST-IE were developed as a part of a research project. The current study is an outcome of this project.
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The SPIN-IE had 25 phonemically balanced words as stimuli and an eight-talker
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babble as noise. The speech stimuli and segments of the noise were inserted in two different
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audio tracks. The speech babble was interrupted to avoid auditory fatigue. The duration of the noise segments was semi-random and varied from 310 ms to 620 ms. The duration of the interruption was kept constant at 75 ms. It was however ensured that the interruption was not present during the presentation of a stimulus. The interval between stimuli was kept constant at 5 seconds. The average amplitude of each noise segment was matched with that of each word stimulus to ensure that the signal-to-noise ratio was zero. A 1 kHz calibration tone was inserted prior to the SPIN-IE list. The RAMST-IE had words familiar to children aged 6 years and above. The words were grouped to form tokens containing 3-word to 8-word sequences. The test contained varied number of tokens (groups of words) for the different word sequences. While the 3-
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word and 4-word sequences had two tokens each, the 5-word to 8-word sequences had four tokens each. The total number of words per list was 118. The recorded material was spoken by a female who had a neutral Indian-English accent. Within each token, the inter-stimulus
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interval between words was 500 ms. This inter-stimulus interval was uniform for all word sequence. Between tokens, the inter-stimulus interval varied depending on the length of the
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word sequence. An inter-stimulus interval of 6 seconds was used between the tokens for the 3-, 4- and 5-word sequences, and was increased to 12 seconds for the 6-, 7- and 8-word
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tokens. The duration of the interval between tokens was based on the average time taken by a
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group of 5 children aged 6 to 7 years to respond to the stimuli. A goodness test, carried out on a group of 5 young adults and 5 children aged 6 to 7, confirmed that the quality of the
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recording was good. A 1 kHz calibration tone, inserted prior to the list, was used to adjust the VU meter of the audiometer.
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Procedure
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Prior to evaluation of the participants, consent was obtained from the caregivers, in
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compliance with the ‘Ethical guidelines for bio-behavioural research involving human subjects’ [31] of the All India Institute of Speech and Hearing, Mysore. All four tests were administered on each of the participant. SPIN-IE [28] was used to evaluate monaural auditory separation or closure; DCV,
recorded by Yathiraj [29] was utilized to test auditory integration; DPT, generated and recoded by Gauri [32] using stimuli similar to the original test developed by Musiek [33], was employed to evaluate temporal patterning; and RAMST-IE [30] was used to evaluate higher order cognitive ability associated with auditory processing. All the tests were played through a computer, the output of which was routed through a diagnostic audiometer at 40 dB SL [Ref average pure tone thresholds at 0.5, 1 and 2 k Hz (PTA)] to sound field speakers or
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TDH-39 earphones housed in MX-41/AR supra-aural ear cushions. The order in which these tests were administered was randomized to prevent any test order effect. In addition, for the monaural tests (SPIN-IE & DPT), half the participants were evaluated in the right ear first
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and half in the left ear first, to avoid an ear order effect. The procedure used to administer the test-battery is described below.
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The SPIN-IE was tested in each ear independently, with the participants having to
response sheet.
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repeat the words heard by them. The tester marked the responses as correct or wrong on a Each correct response was awarded a score of ‘1’ and each incorrect
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response was scored as ‘0’. Both raw and percentage scores were noted for each ear of the participants.
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The DCV test responses were obtained by instructing the participants to mark the syllables that were heard through headphones on a response sheet that had multiple choices.
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Double correct responses were calculated by awarding a score of ‘1’ if the responses in both
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ears were correct. A score of ‘0’ was given if the response was incorrect in either of the ears.
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The DPT was administered separately on each ear of the participants. The participants
were instructed to verbally report the pattern of length of the sounds heard. A correct response was given a score of ‘1’ and an incorrect response a score of ‘0’. The RAMST-IE was presented from a computer via an audiometer in two different
ways. Half the participants heard the material through two sound-field speakers, each placed at 450 azimuth at a distance of one meter from the head of the participant. The other half heard the material binaurally through headphones. The two different modes of presentations were used to check if there was any difference in the presentation mode. The output through both transducers was 40 dB SL (ref. PTA). The participants were asked to listen to each word-sequence and repeat the words heard in the same order as they were presented. The 13 Page 12 of 43
responses were noted by the evaluator on a scoring sheet. Both auditory memory and auditory sequencing were scored separately. While calculating auditory memory, a score of ‘1’ was given for each correctly repeated word. To calculate the auditory sequencing score, a
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score of ‘1’ was given only if the words were repeated in the correct order. Both auditory memory and sequencing scores were tabulated.
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Analyses
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Data obtained from the participants were tabulated and subjected to statistical analyses. The mean and standard deviation were calculated separately for data obtained for
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the four tests (SPIN-IE, DCV, DPT, & RAMST-IE) from the males and females in each age group. A mixed design ANOVA with ear as within participant variable and age, gender as
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between participant variables was carried out separately for SPIN-IE and DPT. Further, age
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Results
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memory and sequencing skills.
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and gender effects were investigated using ANOVA for DCV and MANOVA for auditory
The results of the four auditory processing tests (SPIN-IE, DCV, DPT, & RAMST-
IE) are provided, highlighting the effect of age, gender and ear / score within each test. Additionally, the percentage scores across the four tests are compared to determine the age related changes as a function of the auditory process or higher cognitive function that were evaluated.
Effect of gender, ear and age on auditory processes & auditory memory Speech in noise test (SPIN-IE) The mean and standard deviation of the scores obtained for SPIN-IE (Table 1) indicate that the scores in girls and boys increased with age in both ears. A mixed design 14 Page 13 of 43
repeated measure ANOVA, with ear as the within subject variable and age as well as gender as between group variables, showed no significant effect of ear on the scores [F(1, 268) = 0.11, p > 0.05]. Hence, for further analysis of the data, the scores of the left and right ears
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were combined. Between groups analysis showed a significant effect of age [F(4, 268) = 20.57, p < 0.01] but no significant effect of gender [F(1, 268) = 1.21, p < 0.01]. Further,
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there was no significant interaction among any of the variables.
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Pair-wise comparison, after Bonferroni correction (Figure 1) revealed a clear developmental trend with the performance of the 6-year-old children being significantly
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lower than that of all the older age groups. Likewise, the score of the 7-year-old and 8-year old children were significantly different from that of 9- and 10-year-old children.
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Insert Table 1
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Dichotic CV test (DCV)
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Insert Figure 1
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From the mean and standard deviation of the double correct scores for different age groups (Table 2), it can be observed that with increase in age the scores steadily increased. There was a high variability in the scores of 6 –year old children.
ANOVA indicated that
there was a significant main effect for age [F(4, 222) = 9.39, p < 0.01] but not for gender [F(1, 222) = 0.23, p > 0.05]. Further, a pair-wise comparison with Bonferroni correction (Figure 2) revealed that only the scores of the 6-year-old children were significantly lower than that of the other age groups. . Insert Table 2 Insert Figure 2.
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Duration Pattern Test (DPT) The descriptive statistics of the DPT (Table 3) shows that the mean scores for the 6year-old children were lower and had high variability when compared to the older children.
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As seen in the other tests, the performance of older children was better than that of younger children, with the performance of the boys and girls being similar. However, the mean scores
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of the left ear were better than that of the right ear in all age groups. A mixed design repeated
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measure ANOVA showed a significant main effect of age [F(1, 270) = 5.22, p < 0.05] as well as ear [F(4, 270) = 31.37, p < 0.01] but no significant difference between the scores of males
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and females [(1, 270) = 0.21, p > 0.05]. There was no two-way or three-way interaction. Pair-wise comparison with Bonferroni correction (Figure 3) highlighted that the
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scores of the 6-year-old children differed significantly from those of all other age groups. On the other hand, the performance of the 7-year-old children did not differ significantly from
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that of the 8-year-old children but it was significantly lower than that of the 9- and 10-year-
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old children. Likewise, the scores of the 8-year-old children did not differ significantly from
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that of the 9-year-old children but differed significantly from that of the 10-year-old children. Although the scores of the 10-year-old children were higher than that of the 9-year-old children, there was no significant difference. Insert Table 3
Insert Figure 3
It can be observed from Figure 3 and Table 3 that the variability was very high in the 6-year-old children. Hence, repeated measure ANOVA was performed after eliminating the data of the 6-year-old children. With the elimination of the 6-year-olds there continued to be
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a significant effect of age [F(3, 234) = 13.67, p > 0.05], however the ear effect that was present earlier disappeared [F(1, 234) = 2.32, p > 0.05].
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Revised Auditory Memory and Sequencing Test in Indian-English (RAMST-IE) As half the participants were tested under headphones and the other half through
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loudspeakers, initially an independent sample t-test was carried out to compare the scores obtained through the two transducers. The results showed no significant difference between
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the two groups for the auditory memory scores [t(275) = 1.48, p > 0.05] as well as the auditory sequencing scores [t(275) = 0.39, p > 0.05]. Hence, the data of the two groups were
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combined for further analysis. The mean and standard deviation of the combined scores obtained on the RAMST-IE, in general tended to be higher with increase in age (Table 4).
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This can be observed for both auditory memory and sequencing scores. From Table 4 it is also evident that the mean memory scores were much higher than the mean sequencing
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scores. This pattern was constant across all the five age groups. MANOVA indicated the
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presence of a significant age effect for both memory [F(4, 272) = 11.74, p < 0.01] and
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sequencing [F(4, 272) = 6.46, p < 0.01] scores. Gender did not have a significant effect on memory [F(1, 272) = 1.95; p > 0.05] or sequencing scores [F(1, 272) = 0.73, p > 0.05]. Additionally, there was no significant interaction between age and gender for the memory scores [F(4, 272) = 2.25, p > 0.05] and for the sequencing scores [F(4, 272) = 0.1.82, p > 0.05].
Insert Table 4
Pair-wise comparisons with Bonferroni corrections were carried out to determine how the different age groups varied from each other (Figure 4a & 4b). It was observed that the mean auditory memory scores of the 6-year-old children were significantly lower than that of the 8-, 9- and 10-year-old children.
Similarly, the 7-year-old and 8-year-old children
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performed significantly poorer than the 9- and 10-year-old children.
For the auditory
sequencing scores, the younger children (6-, 7-, & 8-year-olds) performed significantly poorer than the older children (9- & 10-year-olds). However, the sequencing scores were not
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significantly different among the younger or among the older children.
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Insert Figures 4a & 4b.
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Insert Table 5 Developmental trends for different tests
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The mean raw scored of the performance of the five age groups on the four tests (SPIN-IE, DCV, DPT, & RAMST-IE) were converted to percentage. The percentage was It can be observed from Figure 5 that
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calculated as the maximum scores of each test varied.
auditory sequencing was the most difficult task and understanding speech in noise was the
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easiest task for children in most of the age groups. A non-linear increase in performance,
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with a steep change from 6 to 7 years followed by a relatively gradual increase after 7 years
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of age, was observed for the scores of all the tests except auditory memory and sequencing. Compared to the other tests, the auditory memory and sequencing abilities showed lesser enhancement in scores with increase in age. SPIN-IE was the only test where the children did not have a steady increase in performance with increase in age. While the scores of most of the tests showed a plateau after 9 years of age, the scores of the DPT continued to increase till 10 years of age, though the pair-wise comparison did not show a statistically significant difference. The scores of DCV test showed a plateau after 8 years of age but the percentage scores were lesser than that of SPIN-IE. Insert Figure 5.
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Thus, the results indicated that depending on the test (SPIN-IE, DCV, DPT & RAMST-IE), the performance of children of different ages differed.
No significant
difference was observed between the performance of the 7- and 8-year-old children as well as
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the 9- and 10-year-old children on any of the tests. This is evident from Table 5 and Figure 5 that provide a summary of the significance of difference in the performance of the five age
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groups for each of the tests.
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Discussion
The findings of the study indicate that the performance of children on auditory
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processing or higher cognitive functioning tests increase with age.
The gender of the
participants was found to have no effect on the test performance. Additionally, there was no This indicates that auditory
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interaction of gender with age or ear for any of the tests.
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processing is similar in boys and girls aged 6 to 10 years. Thus, it can be construed that for clinical purposes, separate norms for males and females are unnecessary. Earlier studies have
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also reported of no gender differences in tests for auditory processing or higher cognitive functioning. These tests include speech-in-noise [12], DCV [34], DPT [35] as well as auditory memory and sequencing [36-38]. Neuroimaging studies of the brain of girls and boys have documented structural differences in the volume of the brain [39]. It can be construed that the structural changes reported in the brain of males and females are not significant enough to result in differences in auditory processing abilities. The performance across the two ears, evaluated for DPT and SPIN-IE, were found to be alike. Similar to the present study, the results of earlier investigations [18, 32] showed the absence of an ear effect for DPT. However, the ear effect has not been reported for speech perception in noise by the majority of the investigators who have studied this aspect. 19 Page 18 of 43
Findings regarding the age of the participants, in the current study revealed that most of the tests can be administered on children as young as 6 years of age. In general, the 6 year old children performed significantly poorer than the older age groups in most of the tests. An
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exception to this was their performance in the RAMST-IE. Additionally, it was observed that the 7 year old children did not differ significantly from the older children, especially from the
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adjacent older group. This indicates that the change in performance was very gradual from 7 to 8 years. However, there continued to be a significant increase in performance as the
Although there was no significant difference between the
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Table 5 and Figure 5.
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children grew older. The growth in performance varied from test to test, as can be seen in
performances of 9 and 10 year old children, the scores did not show a plateau, especially for
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DPT. Thus, the study highlights that age related changes continue even in the older age groups that were evaluated. The general increase in performance with age, observed in all
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the tests, substantiates the need to obtain age appropriate normative data.
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The results obtained in the study are similar to those reported in literature earlier. The
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effect of age has been demonstrated for the speech-in-noise test [40, 41], DCV test [12, 42] , DPT [18, 43] as well as auditory memory and sequencing test [37, 38, 44]. Although a direct comparison across studies is difficult as the age ranges studied and the stimuli used vary from study to study, the consensus is that performance on auditory processing tests improves with age. The findings of the present study indicate that although the auditory processes that were studied do not improve significantly in children from 9;11 years to 10;11 years, a marginal improvement was seen. These results reinforce the consensus that the auditory processing is not mature till 11 years of age. The age related changes in performance have been attributed to morphological changes that occur in the central auditory pathway. Luders, Thompson and Toga [45] observed an increase in the thickness of the corpus callosum in children in the age range of 5 20 Page 19 of 43
to 18 years and ascribed it to an increase in myelinated fibers. Based on a longitudinal MRI study of the brain in children aged 4 to 20 years, Giedd et al. [46] reported an increase in white matter and gray matter of the cortex in the preadolescent years. They further observed
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that increase in gray matter in the temporal lobe was non-linear and region-specific. In the current study, with increase in age, non-linear improvement in auditory processing was
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observed. Thus, it can be inferred that the age related structural changes result in age related changes in processing of auditory signals. Investigations correlating neuroimaging findings Recommendation to
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with results of audiological tests are required to corroborate this.
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conduct auditory processing tests only in children older than 7 years has led researchers to rarely provide auditory processing test norms for children younger than 7 years of age.
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ASHA [22] does not advocate testing auditory processing in children having a mental age below 7 years as they are likely to find the task difficult, thereby affecting the test results.
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Similarly, as per the AAA [47] guidelines for the ‘Diagnosis, Treatment and Management of
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Children and Adults with Central Auditory’, auditory processing tests are recommended to be carried out on those with a “minimum developmental age of seven or eight years, or a level of
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cognitive functioning that is consistent with this age range” (pp 14). However, from the findings of the present study, it is evident that it is possible to carry out certain auditory processing tests (SPIN-IE , DCV and RAMST-IE) on children as young as 6 years of age. Despite the 6 year old children obtaining significantly poorer scores than older children on most of these tests, the variability in performance was similar or less than that obtained by the older children for these three tests. As the variability in performance in this age group was not very large, the normative data obtained on them can be utilized usefully to make early diagnosis of the condition. Unlike most studies reported in literature, Stollman, Neijenhuis et al. [12], in a study on Dutch children, also demonstrated that tests for auditory processing can be conducted on children as young as 4 years of age.
21 Page 20 of 43
While the 6-year-old children in the current study were able to carry out most of the tests, the results indicate that it is difficult to administer DPT in this age group. It was observed that on this test, only two children obtained scores greater than 21, while 6 obtained
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scores between 10 and 20 and the remaining got scores of 0. The response mode used in the present study required linguistic labeling of the pattern that was heard. This probably made
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the task difficult as it tapped temporal processing as well as inter-hemispheric functioning. It has been reported that the functional development of inter-hemispheric connection undergoes
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a significant change between 6 to 8 years of age [48]. Thus, DPT requiring verbal responses
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is not a good test to assess temporal processing in 6-year-old children. It needs to be investigated if the performance would be better for humming responses.
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Double correct scores on DCV also showed large variability suggesting that binaural integration skills are difficult for 6- year old children.
DCV again taps the functioning of
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both the hemispheres as well as interhemispheric connections. The results obtained on
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double correct scores of DCV substantiates that there is a difference in the maturation rate of The single correct scores were not
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corpus callosum within children of this age group.
considered for analysis in this study, however it was observed that there was not much variability for single correct scores of 6 year old children. Hence it is suggested that while interpreting scores of 6 year old children on DCV, single correct scores can be used reliably but the double correct scores need to be interpreted with caution. Thus, in the present study, the comparison of performance of the children indicated
that auditory closure and monaural separation abilities, assessed by SPIN-IE, is developed early in childhood and stabilizes by 9 years of age. However, for DPT, the relatively poorer performance seen in the younger age group could either be on account of temporal ordering being developed later or due to immature corpus callosum. The latter would have resulted in the children that have difficulty in labeling the tones heard by them. The former can be 22 Page 21 of 43
confirmed only by evaluating DPT using humming responses. The results of DCV test suggest that auditory capacity to integrate stimuli heard in the two ears is very poor in 6-yearold children and reaches a plateau by 9 years of age. It is not clear whether poor auditory
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integration is due to immature auditory system or due to immature cognitive functioning. The performance of the children on the RAMST-IE varied depending on whether
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memory or sequencing abilities were assessed. In general it was observed that children in all
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age groups performed better when the ‘memory’ scores were calculated compared to when ‘sequencing’ scores were calculated. This can be attributed to the difficulty of the tasks. In
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the latter scoring procedure, the children were required to not only remember the words but also the correct sequence, while in the former scoring procedure they were not required to Although there were differences in the scores for
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remember the order of the stimuli.
‘memory’ and ‘sequencing’, both types of scores improved with increase in age. For the
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memory scores, the younger three age groups did not differ from those in the adjacent age
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groups (i.e. 6 year olds did not differ from the 7 year olds and the 7 year olds did not differ
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from the 8 year olds). Likewise, the oldest two age groups did not differ from each other. An almost similar trend was seen for the sequencing scores also. In general it can be noted that in the younger (6 to 8 year olds) and older age groups (9 to 10 year olds), the growth in auditory memory and sequencing was more gradual. However, it was more rapid between 8 to 9 years of age (Table 5).
The findings of auditory memory and sequencing are similar to what has been
reported in the literature. Gathercole et al. [37] also observed a significant age effect for auditory memory in children aged 4 years to 15 years using word, digit and non-word tasks. Similarly, Devi et al. [36] reported an increase in auditory memory with increase in age on an auditory memory and sequencing test in English, in children aged 6 to 12 years. Their results indicated that auditory memory scores increased with an advance in age up to ten years, after 23 Page 22 of 43
which a plateau was obtained. In a similar manner, Yathiraj and Vijayalakshmi [38] also found a significant age effect on a Kannada auditory memory and sequencing test in children aged 5 to 11 years. A significant difference was observed between each of the seven age
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groups. From the findings of the present study, it can be inferred that performance on all four
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tests that were evaluated (SPIN-IE, DCV, DPT & RAMST-IE) did improve with age.
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However, the rate at which the changes that took place varied from test to test. While certain tests had a steep increase in scores with increase in age (DCV & DPT) others had a gradual
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increase with age (RAMST-IE & SPIN-IE). Thus, it can be construed that different auditory processes have different rates of development, which is a reflection of the development of the
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different areas controlling the processes.
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Conclusion
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The present study was carried out with the aim to determine age related changes on a battery of four auditory processing tests (SPIN-IE, DCV, DPT and RAMST-IE) in 280
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typically developing children aged 6 to 10 years. The tests tapped auditory closure or monaural separation, binaural auditory integration abilities, temporal processing abilities as well as auditory memory and sequencing abilities. The study also determined the effect of gender for each of the tests. Ear effect was computed for the monaural tests that were evaluated (SPIN-IE & DPT). Analyses of the data showed that the older children performed better than the younger children. Although age had an effect on the results of all the tests, the rate of improvement in performance varied across the tests. A non-linear growth in performance with increase in age was observed for all four tests that were administered. The results indicated that the assessment of auditory processing abilities can be carried out on children as young as 6 years. The 6-year-old children could be tested using all the tests
24 Page 23 of 43
except DPT. While children aged 7 years and above could perform the DPT, those aged 6 years found the task too difficult and hence it is recommended that it should not be included in the test battery for children below 7 years of age. While evaluating 6 year children on
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DCV, double correct scores need to be interpreted with caution. Further, there was no significant difference between the performance of boys and girls. The performance in the
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two monaural tests (SPIN-IE & DPT) was similar in the right and left ears.
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Acknowledgements
This study is an outcome of a research project funded by the All India Institute of
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Speech and Hearing, Mysore. The All India Institute of Speech and Hearing, Mysore and Bharati Vidyapeeth Deemed University, Pune are acknowledged for providing the facilities to
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carry out the project. The contribution of Ms. Muthuselvi T., research officer in the project, is
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collected data at Pune.
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highly appreciated. Mr. Swarup Mishra and Ms. Aparna Oak are acknowledged for having
References
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[7] A. Mäenpää. Auditory processing in the two hemispheres in developing brain: MEG study [Master's thesis]. Department of Psychology: University of Jyväskylä; 2013. [8] N.E. Amos, L.E. Humes. SCAN test-retest reliability for first-and third-grade children. Journal of Speech Language and Hearing Research. 41(4)(1998):834-46. [9] R.W. Keith. Development and standardization of SCAN-A: Test of auditory processing disorders in adolescents and adults. J Am Acad Audiol. 6(4)(1995):286-92. [10] R.W. Keith. Development and standardization of SCAN-C test for auditory processing disorders in children. J Am Acad Audiol. 11(8)(2000):438. [11] K.A.M. Neijenhuis, A. Snik, G. Priester, S. van Kordenoordt, P. van den Broek. Age effects and normative data on a Dutch test battery for auditory processing disorders. Int J Audiol. 41(2002):334-46. [12] M.H.P. Stollman, K.A.M. Neijenhuis, S. Jansen, H.M.F. Simkens, A.F.M. Snik, van den Broek P. Development of an auditory test battery for young children: a pilot study. Int J Audiol. 43(2004):330-8. [13] M.H.P. Stollman, E.C. van Velzen, H.M. Simkens, A.F. Snik, P. van den Broek. Development of auditory processing in 6-12-year-old children: a longitudinal study. Int J Audiol. 43(1)(2004):3444. [14] Y. Shtyrov, T. Kujala, R.J. Ilmoniemi, R. Näätänen. Noise affects speech-signal processing differently in the cerebral hemispheres. Neuroreport. 10(1999):2189–92. [15] S. Anderson, E. Skoe, B. Chandrasekaran, N. Kraus. Neural timing is linked to speech perception in noise. The Journal of Neuroscience. 30(14)(2010):4922-6. [16] R. Efron, P.H. Crandall, D. Koss, P.L. Divenyi, E.W. Yund. Central auditory processing. III. The “Cocktail Party” effect and anterior temporal lobectomy. Brain Lang. 19(1983):254-63. [17] F.E. Musiek, M.L. Pinheiro. Frequency patterns in cochlear, brainstem, and cerebral lesions. Audiology. 26(2)(1987):79-88. [18] F.E. Musiek, J.A. Baran, M.L. Pinheiro. Duration pattern recognition in normal subjects and patients with cerebral and cochlear lesions. Int J Audiol. 29(6)(1990):304-13. [19] S.P. Springer, M.S. Gazzaniga. Dichotic testing of partial and complete split brain subjects. Neuropsychologia. 13(1975):341-6. [20] R. Isaacson, K. Pribram. The Hippocampus. New York: Plenum Press; 1986. [21] J.J. Lister, R.A. Roberts, F.L. Lister. An adaptive clinical test of temporal resolution: age effects. Int J Audiol. 50(6)(2011):367-74. [22] American Speech-Language-Hearing Association. (Central) auditory processing disorder (technical report) (2005). [23] A. Yathiraj, K. Mascarenhas. Auditory profile of children with suspected auditory processing disorder. Journal of Indian Speech and Hearing Association. 18(2004):6-14. [24] J.C. Raven. Standard and Coloured progressive matrices: Sets A, AB, B. Oxford, England: Oxford Psychologists; 1952. [25] Mayadevi. Development and standardization of a common speech discrimination test for indians. Mysore, India: Masters independent project submitted to the University of Mysore; 1974. [26] L.L. Lee. The Northwestern Syntax Screening Test. Chicago: Northwestern Univ Press; 1969. [27] ANSI S3.1-1999. American National Standard Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms (Standard S3.1) New York: American National Standards Institute. [28] A. Yathiraj, C.S. Vanaja, T. Muthuselvi. Speech-in-noise test in Indian-English (SPIN-IE). Developed as part of the project ‘Maturation of auditory processes in children aged 6 to 10 years’ completed in 2012. Department of Audiology, Mysore, India: All India Institute of Speech and Hearing; (2010). [29] A. Yathiraj. The Dichotic CV test. Material developed at the Department of Audiology. Mysore, India: All India Institute of Speech and Hearing (1999). [30] A. Yathiraj, C.S. Vanaja, T. Muthuselvi. Revised Auditory Memory and Sequencing Test in Indian-English. Developed as part of the project ‘Maturation of auditory processes in children aged 6 to 10 years’ completed in 2012. Department of Audiology, Mysore, India: All India Institute of Speech and Hearing; (2010). [31] Ethical Guidelines for Bio-Behavioural Research Involving Human Subjects. Mysore, India: All India Institute of Speech and Hearing; (2007).
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[32] D.T. Gauri. Development of norms on duration pattern test. Mysore, India: Master’s independent project submitted to the University of Mysore; 2003. [33] F.E. Musiek. Frequency (Pitch) and duration pattern tests. J Am Acad Audiol. 5(1994):265-8. [34] D.W. Moncrieff, R.H. Wilson. Recognition of randomly presented one-, two-, and three-pair dichotic digits by children and young adults. J Am Acad Audiol. 20(1)(2009):58-70. [35] M.D. Turkyilmaz, S. Yilmaz, S. Yagcioglu, M. Yarali, N. Celik. Computerised Turkish versions of tests for central auditory processing disorder. Journal of Hearing Science. 2(1)(2012):30-5. [36] N. Devi, S. Nair, A. Yathiraj. Auditory memory and sequencing in children aged 6 to 12 years. Journal of the All India Institute of Speech and Hearing. 27(2008):96-101. [37] S.E. Gathercole, S.J. Pickering, B. Ambridge, H. Wearing. The structure of working memory from 4 to 15 years of age. Dev Psychol. 40(2)(2004):177-90. [38] A. Yathiraj, C.S. Vijayalakshmi. Kannada auditory memory and sequencing test. Mysore: All India Institute of Speech and Hearing; 2006. [39] A.L. Reiss, M.T. Abrams, H.S. Singer, J.L. Ross, M.B. Denckla. Brain development, gender and IQ in children: a volumetric imaging study. Brain. 119(1996):1763-74. [40] M. Fallon. Children's perception of speech in noise: University of Toronto; 2001. [41] D. Lewis, B. Hoover, S. Choi, P. Stelmachowicz. The relationship between speech perception in noise and phonological awareness skills for children with normal hearing. Ear Hear. 31(6)(2010):761-8. [42] G. Krishna. Dichotic CV test – Revised normative data for children. Mysore: Master’s independent project submitted to the University of Mysore; 2001. [43] F.E. Musiek, K. Kibbe, J.A. Baran. Neuroaudiological results from split-brain patients. Seminars in Hearing. 5(03)(1984):219-29. [44] N. Cowan, L.D. Nugent, E.M. Elliott, I. Ponomarev, J.S. Saults. The role of attention in the
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Dev. 70(5)(1999):1082-97. [45] E. Luders, P.M. Thompson, A.W. Toga. The development of the corpus callosum in the healthy human brain. The Journal of Neuroscience. 30(33)(2010):10985-90. [46] J.N. Giedd, J. Blumenthal, N.O. Jeffries, F.X. Castellanos, H. Liu, A. Zijdenbos, et al. Brain development during childhood and adolescence: a longitudinal MRI study. Nat Neurosci. 2(10)(1999):861-3. [47] F.E. Musiek, J.A. Baran, T.J. Bellis, G.D. Chermak, J.W. Hall, R.W. Keith, et al. Guidelines for the diagnosis, treatment and management of children and adults with central auditory processing disorder. American Academy of Audiology. (2010). [48] M.T. Banich, W.S. Brown. A life-span perspective on interaction between the cerebral hemispheres. Developmental Neuropsychology. 18(2000):1-10.
Annexure 1
Sample of Test Material used for the study
Insert Figure A Insert Figure B Insert Figure C
27 Page 26 of 43
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Insert Table A
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Table 1: Mean and SD scores for SPIN-IE Right ear
Left ear
Age in Years M
F
T
M
F
T
15.37 16.27 14.72
15.42
SD
4.09
3.96
3.91
4.08
3.86
4.00
18.41 18.90 18.20
SD
3.53
7 3.87
4.11
3.75
3.92
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3.25
18.56
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Mean 18.54 18.27
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Mean 16.56 14.41 6
Mean 18.07 17.27
17.66 17.53 17.53
17.53
SD
3.27
3.58
3.52
3.01
3.46
3.76
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8
Mean 21.34 21.06
21.20 21.44 20.12
20.76
SD
2.08
2.44
9 2.27
M
1.87
1.84
2.77
Mean 19.50 20. 63 19.81 19.50 20. 34 19.95 10 5.05
3.37
4.21
4.81
3.85
4.30
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SD
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Note. M = Males; F = Females; T = Males + Females
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Maximum possible score on SPIN-IE = 25
29 Page 28 of 43
Table 2: Mean and SD of the double correct scores on dichotic CV test across the age groups Double correct score Age in years T
Mean
5.7
5.27
5.46
SD
6.54
5.54
5.92
Mean
10.51 9.68
10.11
SD
5.19
4.92
Mean
11.96 12.60 12.28
SD
5.85
Mean
14.34 13.74 14.03
SD
5.81
6
4.66
8
Mean 10
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6.56
6.32
13.39 12.78 13.06 5.87
5.16
5.46
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SD
6.85
M
9
7.28
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7
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F
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Note. M = Males; F = Females; T = Males + Females
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Maximum possible single / double correct score = 30
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Table 3: Mean and SD of scores obtained for the Duration Pattern Test Right ear
Left ear
Age in years F
T
M
F
T
Mean
6.66
4.73
5.60
7.27
5. 54
6.32
SD
6.76
3.91
5.40
7.45
4.90
6.15
Mean
11.03 13.48 12.21 11.54 13.48 12.48
SD
5.67
Mean
15.90 14.20 15.05 15.66 15.16 15.41
SD
6.19
Mean
17.06 17.19 17.13 17.24 17.35 17.30
SD
4.23
Mean
19.85 19.28 19.55 20.82 18.96 19.83
SD
6.10
cr
6
7 7.34
8
9
M
5.95
7.47
6.81
7.05
6.48
7.06
3.46
6.43
7.11
7.28
6.72
5.60
6.90
d
10
7.27
6.75
8.16
an
7.26
5.80
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8.71
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M
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Note. M = Males; F = Females; T = Males + Females
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Maximum possible duration pattern score = 30
31 Page 30 of 43
Table 4: Mean and SD of scores obtained for auditory memory and sequencing
Memory
Sequencing
Age in years
9
T
Mean
50.27 51.82 50.95 33.68 37.83 35.49
SD
8.97
Mean
49.41 55.97 52.80 39.23 34.24 36.82
SD
8.65
Mean
58.26 54.2
SD
11.95 11.85 11.98 12.83 11.03 12.06
Mean
60.97 61.66 61.3
SD
13.32 6.03
Mean
59.77 63.78 61.71 43.63 47.68 45.59
SD
10.03 12.41 11.32 12.06 16.78 14.54
8.52
10.97 7.91
9.46
7.39
8.61
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8.09
10.50 9.59
10.27
56.23 40.70 36.40 38.55
44.16 41.62 42.93
10.37 15.52 10.10 13.14
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10
F
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8
M
M
7
T
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6
F
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M
Note. M = Males; F = Females; T = Males + Females;
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Maximum possible memory score = 118; Maximum possible sequence score = 118.
32 Page 31 of 43
Table 5: Summary of the effect of age of the participants on the four tests (SPIN-IE, DCV, DPT & RAMST-IE) RAMST-IE -
RAMST-IE -
Memory
Sequencing
7
8
9
10
7
9
10
7
6
**
NS
**
**
** ** ** ** ** ** **
**
NS
NS
**
NS
**
**
8 9
NS
9
10
**
*
NS
NS
8
NS
**
**
NS
**
NS
NS
8
9
** **
10
7
8
9
10
**
NS
NS
**
**
NS
**
NS
**
**
**
*
**
** ** NS
NS
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NS
7
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7
8
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DPT#
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DCV – DC
Age
SPIN-IE #
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Note. ** = p < 0.01; * = p < 0.05; NS = Not significant; # Average of left and right ears
33 Page 32 of 43
Table A. Sample of the word sequences of RAMST-IE
Rose Rope Shout Skirt Tap Sing
Stick Pull Run Head Plate
Cake Door Sky Cloud
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Car Chips Fast Rich Bus Rat
Mouth Flag Duck
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Dog Home Joy Hide Wright Class
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Stimuli
Soup Bring
Pray
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Word Sequence 3-word 4-word 5-word 6-word 7-word 8-word
34 Page 33 of 43
Captions for Figures Fig.1: Pair-wise comparison of age effect on SPIN-IE score
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Fig 3: Pair-wise comparison of age effect on Duration Pattern Test
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Fig2: Pair-wise comparison of age effect on DCV-DC score
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Fig 4: Pair-wise comparison of age effect on auditory memory (4a) and auditory sequencing (4b)
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Fig.5: Mean percentage scores of the different tests (SPIN-IE, DCV, DPT, RAMST-
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IE)
Fig A: Sample SPIN-IE with speech (bird, grapes, step, cloud) in upper track and
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noise in lower track, with both tracks being directed to one channel / ear
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Fig B: Sample waveform of DCV
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Fig C: Sample waveform of DPT
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S0165-5876(15)00238-4 http://dx.doi.org/doi:10.1016/j.ijporl.2015.05.018 PEDOT 7594
To appear in:
International Journal of Pediatric Otorhinolaryngology
Received date: Revised date: Accepted date:
21-2-2015 13-5-2015 16-5-2015
Please cite this article as: A. Yathiraj, C.S. Vanaja, Age Related Changes in Auditory Processes in Children Aged 6 to 10 years, International Journal of Pediatric Otorhinolaryngology (2015), http://dx.doi.org/10.1016/j.ijporl.2015.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Age Related Changes in Auditory Processes in Children Aged 6 to 10 years
1
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Asha Yathiraj1 and C S Vanaja2
Professor of Audiology
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Email: [email protected]
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All India Institute of Speech and Hearing, Mysore, India
2
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&
Professor of Audiology,
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School of Audiology & Speech language pathology
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Bharati Vidyapeeth Deemed University, Pune, India
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Email: [email protected]
Corresponding author: C S Vanaja
Professor of Audiology Bharati Vidyapeeth Deemed University School of Audiology & Speech Language Pathology, Pune, Maharashtra - 411043, India Email: [email protected] 1 Page 1 of 43
Age Related Changes in Auditory Processes in Children Aged 6 to 10 years
1
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Asha Yathiraj1 and Vanaja Chitnahalli Shankarnarayan2
Professor of Audiology
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Email: [email protected]
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All India Institute of Speech and Hearing, Mysore, India
2
M
&
Professor of Audiology,
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School of Audiology & Speech language pathology
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Bharati Vidyapeeth Deemed University, Pune, India
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Email: [email protected]
Corresponding author: C S Vanaja
Professor of Audiology Bharati Vidyapeeth Deemed University School of Audiology & Speech Language Pathology, Pune, Maharashtra - 411043, India Email: [email protected] 3 Page 2 of 43
Abstract Objectives:
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The study evaluated age related changes in auditory processing (separation / auditory closure, binaural auditory integration abilities, temporal processing abilities) and higher order
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cognitive function (auditory memory & sequencing abilities) in children. Additionally, the study aimed to assess the effect of gender on the auditory processes / higher cognitive
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function as well as ear effect for the monaural tests that were administered.
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Methods:
The cross-sectional experimental study evaluated 280 typically developing children
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aged 6 to 10 years, divided into five age groups. They were evaluated on auditory processes / higher order cognitive functions reported to be frequently affected in children with auditory
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processing disorders (Speech-in-Noise Test in Indian-English, Dichotic consonant-vowel test,
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Results:
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Duration pattern test, & Revised Auditory Memory and Sequencing Test in Indian-English).
ANOVA and MANOVA revealed no significant gender effect in all four tests.
However, a significant age effect was seen, with the rate at which maturation occurred, varying across the tests. Conclusions:
Thus, the findings indicate that different auditory processes have different rates of development. This reflects that the areas responsible for different auditory processes / higher cognitive function do not develop at the same pace. Key words: Separation, integration, temporal processing, auditory memory 4 Page 3 of 43
Introduction Auditory processing is a complex phenomenon and consists of many processes that include auditory closure or separation, binaural integration, and temporal processing. Studies
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have indicated that children with auditory processing deficits frequently have difficulties in auditory separation or closure [1-3], binaural integration [1, 2, 4], and temporal processing [2,
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4]. Additionally, auditory memory, a higher order cognitive function has also been found to
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be frequently affected in them [2].
Age related changes of these processes or cognitive function in normal children have
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been used to determine their development. Furthermore, such age related changes have been used in the identification and management of children with auditory processing disorders.
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These age related changes can be attributed to the maturation of the brain. It has been substantiated that the cortical system is immature in children and continues to develop in
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adolescents [5-7]. Past research also indicates that different auditory processes do not mature
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in a similar manner but take different maturational courses [8-13]. A possible reason for the
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difference in maturation could be on account of the different cortical or brainstem areas that control them.
Perception of speech in noise, an auditory separation or closure process, involves
perception of spectro-temporal cues to identify the signal as well as ability separate signal from the background noise. Perception of speech in the presence of noise has been observed to result in reduced activity of the left hemisphere along with increased activity in the right hemisphere [14]. It has also been observed that noise entwined with speech results in a neural delay that makes it difficult to segregate the two at the brainstem and cortex [15]. Earlier, Efron, Crandall, Koss, Divenyi, and Yund [16] implied that the anterior temporal lobe was
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responsible for perception of speech in the presence of noise since individuals with lesions in this region exhibited difficulty in the task. Duration pattern test, a test for assessing temporal processing, requires discrimination
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of duration, perception of patterns or sequence as well as the ability to indicate the pattern heard. Functioning of both the hemispheres as well as the corpus callosum is required for Auditory integration, as assessed by dichotic
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giving verbal response on this test [17, 18].
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stimuli, involves the presentation of two different stimuli to the two ears simultaneously, both of which have to be identified by the listener. Dichotic tests are known to assess laterality,
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specialization of the auditory cortex in addition to the functioning of the two hemispheres and corpus callosum [19]. Likewise, auditory memory is reported to depend on the functioning of
[20].
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the hippocampus and amygdala that are located in the anterior temporal region of the brain The changes with age, in the areas responsible for the development of different
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auditory processes, may find a parallel with the behavioral development of the same.
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Auditory processes have been reported to start developing after birth and continue to
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develop as the child grows older, in line with the development of the central auditory nervous system. Keith [9] noted that those aged 12 to 50 years performed similarly on the six subtests (2 filtered words subtests, 2 auditory figure-ground subtests, a competing words & a competing sentences subtest) of SCAN-A.
It can be construed from these findings that
auditory closure or separation matures by 12 years of age. Further, Keith in 2000 reported the mean raw score of SCAN-C increased and the standard deviations decreased with increasing age in children aged 5 years to 11 years and 11 months. This variation in performance with increase in age was considered to reflect the maturation of the central auditory nervous system. Keith [9, 10] did not report whether the variation in performance across the ages was statistically significant or not. However, an investigation by Amos and Humes [8] did demonstrate the presence of a statistically significant difference in SCAN 6 Page 5 of 43
scores in children aged 6 and 9 years (first graders & third graders). Thus, these findings substantiate the presence of maturational changes in an auditory closure or separation task. A review of literature indicates that variation in scores across ages depends not only
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on the process evaluated, but also on the type of material used while evaluating a particular process. For example, Neijenhuis et al. [11] found no significant difference in a word-in-
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noise test scores obtained by adolescents (aged 14-16 years) and by adults whereas they
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observed a significant difference between the two age groups for a sentence-in-noise test. Thus, depending on the type of stimuli used, maturation of auditory closure or separation task
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varied. Similar to the word-in-noise test performance, Neijenhuis et al. [11] reported of no significant difference between adolescents and adults on a dichotic digit test. Additionally,
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they also noticed that in children aged 6 to 16 years there was no age effect for a frequency pattern test. However, they reported of an age effect on seven other tests carried out in this
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age group (words-in noise, filtered speech, binaural fusion, dichotic digits, duration patterns,
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backward masking, digit span). Based on their findings they concluded that maturation
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continues to develop even in adolescents.
Similar to the findings of research on auditory closure or separation, the procedure
and stimuli has been found to affect the results of tests for temporal processing. Lister, Roberts, and Lister [21] observed that performance of 11 to 12 year old children was similar to that of adults on a gap detection test whereas the performance of the 7 to 8 year and 8 to 9 year old children were poorer that of adults. They reported that the developmental effects observed by them were greater than most of those reported previously. Lister et al. [21] attributed this difference to variations in stimuli and procedure used. Maturational effects up to 12 years have also been documented by Stollman, Velzen, et al. [13], based on the findings of a longitudinal study of 20 children aged 6 years through
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7, 8, 10 and 12 years. This was seen for 9 tests (filtered speech test, binaural fusion test, frequency pattern test, duration pattern test, auditory word discrimination test, an auditory synthesis test, an auditory closure test, & a number recall test), but not for a speech-in-noise
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test. They noticed that in all ages, the children performed significantly poorer than their adult group, indicating that the processes evaluated continued to develop even after 12 years of
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age. Their findings substantiate the findings of Neijenhuis et al. [11] who also observed that
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maturation continued through adolescence.
Due to the large variability in results, it has been recommended that tests used for the
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evaluation of auditory processing should not be administered on children below the age of 7 years [22]. However, Stollman, Neijenhuis et al. [12] demonstrated that auditory processing
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tests that evaluated sustained auditory attention, binaural hearing, temporal processing, and phonological coding could be carried out effectively in children aged 4 to 6 years of age.
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Although no gender difference was observed, the older children were found to perform better
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than the younger children on the battery of tests. The difference was most prominent for the
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dichotic word test and the phoneme awareness test. From the review of literature, it is evident that there exist considerable variations
regarding the age related changes of the different auditory processes.
This has been
attributed to different auditory processes requiring different levels of functioning in the auditory system. There is a need for additional information in the area of age related changes in auditory processing to substantiate the developmental pattern seen in different auditory processes. Thus, the current study was carried out with the aim to determine age related changes in the performance of children on tests assessing different auditory processes or higher cognitive abilities (auditory closure or separation, temporal patterning, binaural integration, & auditory memory and sequencing). Additionally, the study aimed to evaluate
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the effect of gender as well as the performance across the two ears for the auditory processes or higher cognitive abilities.
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Methods Using a cross-sectional experimental design, age related changes on a battery of
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auditory processing tests were evaluated on 280 normal hearing children who were divided into five age groups. The battery consisted of four different tests that tapped different
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auditory processes or cognitive ability associated with auditory processing.
The tests
evaluated monaural auditory separation or closure, binaural auditory integration, temporal
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patterning, and auditory memory. These aspects of auditory processing were selected since they have been noted to be more frequently affected in children with auditory processing
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disorder.
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Participant selection
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The participants consisted of 280 school-going children (140 male & 140 female) in
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the age range of 6 to 10 years. The participants were recruited from two different centers in India having similar test facilities, one located in Mysore and the other in Pune. The participants tested in the two centers were matched in terms of gender and age. It was ensured that children were ‘not at-risk’ for auditory processing disorder, based on the ‘Screening Checklist for Auditory Processing’ developed by Yathiraj and Mascarenhas [23]. The children were categorized into five age groups (6 to 6;11 years, 7 to 7;11 years, 8
to 8;11 years, 9 to 9;11 years, & 10 to 10;11 years). The youngest age group had 40 children and the four remaining age groups had 60 children each. All the children had average or above average IQ on the Raven’s Progressive Colored or standard Matrices [24]. They attended schools where the instruction was in English and were reported by their teachers to
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be proficient in the language. Additionally, they were all reported to be right handed. Only those children with air conduction and bone conduction thresholds less than 15 dB HL in the octave frequencies 250 Hz to 8 kHz and 250 Hz to 4 kHz respectively, were included in the
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study. To confirm the presence of normal middle ear functioning, the participants were required to have 'A’ type tympanograms with ipsilateral and contralateral acoustic reflexes
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present for the frequencies 500 Hz, 1 kHz and 2 kHz. In addition, speech identification score in quiet was determined using the ‘Common Speech Discrimination Test for Indians [25], for
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all the participants. This test, with 25 nonsense consonant-vowels, had norms established on
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children. The test, presented through headphones at 40 dB SL, was utilized to confirm that the participants had normal speech identification scores in quiet. Only those with scores
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greater than 85% in quiet were included in the study. Additionally, the participants were required to have age appropriate language, which was assessed using on the Northwestern
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Syntax Screening Test developed by Lee [26].
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Equipment
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A calibrated dual channel diagnostic audiometer (OB 922 - Version 2) with air conduction (TDH-39) and bone conduction (B-71) transducers was used to carry out puretone audiometry, speech audiometry and the auditory processing tests.
The auditory
processing tests were played through a CD using a Compaq Presario 6000 laptop with Intel Pentium dual core processor.
To ensure normal middle ear functioning, a calibrated
immittance meter was utilized. Similar instruments were used in both centers where the data were collected.
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Test Environment All the audiological tests were carried out in a sound treated two-room suite with permissible noise limits as specified by ANSI standards [27]. The screening checklist, the IQ
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test and the language screening tests were administered in quiet, distraction-free rooms.
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Material
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The four auditory processing tests used to evaluate the children enrolled in the study included ‘Speech-in-Noise Test in Indian English’ (SPIN-IE) [28], ‘DCV’ [29], ‘DPT’ [18],
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and ‘Revised Auditory Memory and Sequencing Test in Indian-English’ (RAMST-IE) [30]. A sample of all the test material used for the study is given in Annexure 1. SPIN-IE and
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RAMST-IE were developed as a part of a research project. The current study is an outcome of this project.
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The SPIN-IE had 25 phonemically balanced words as stimuli and an eight-talker
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babble as noise. The speech stimuli and segments of the noise were inserted in two different
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audio tracks. The speech babble was interrupted to avoid auditory fatigue. The duration of the noise segments was semi-random and varied from 310 ms to 620 ms. The duration of the interruption was kept constant at 75 ms. It was however ensured that the interruption was not present during the presentation of a stimulus. The interval between stimuli was kept constant at 5 seconds. The average amplitude of each noise segment was matched with that of each word stimulus to ensure that the signal-to-noise ratio was zero. A 1 kHz calibration tone was inserted prior to the SPIN-IE list. The RAMST-IE had words familiar to children aged 6 years and above. The words were grouped to form tokens containing 3-word to 8-word sequences. The test contained varied number of tokens (groups of words) for the different word sequences. While the 3-
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word and 4-word sequences had two tokens each, the 5-word to 8-word sequences had four tokens each. The total number of words per list was 118. The recorded material was spoken by a female who had a neutral Indian-English accent. Within each token, the inter-stimulus
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interval between words was 500 ms. This inter-stimulus interval was uniform for all word sequence. Between tokens, the inter-stimulus interval varied depending on the length of the
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word sequence. An inter-stimulus interval of 6 seconds was used between the tokens for the 3-, 4- and 5-word sequences, and was increased to 12 seconds for the 6-, 7- and 8-word
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tokens. The duration of the interval between tokens was based on the average time taken by a
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group of 5 children aged 6 to 7 years to respond to the stimuli. A goodness test, carried out on a group of 5 young adults and 5 children aged 6 to 7, confirmed that the quality of the
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recording was good. A 1 kHz calibration tone, inserted prior to the list, was used to adjust the VU meter of the audiometer.
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Procedure
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Prior to evaluation of the participants, consent was obtained from the caregivers, in
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compliance with the ‘Ethical guidelines for bio-behavioural research involving human subjects’ [31] of the All India Institute of Speech and Hearing, Mysore. All four tests were administered on each of the participant. SPIN-IE [28] was used to evaluate monaural auditory separation or closure; DCV,
recorded by Yathiraj [29] was utilized to test auditory integration; DPT, generated and recoded by Gauri [32] using stimuli similar to the original test developed by Musiek [33], was employed to evaluate temporal patterning; and RAMST-IE [30] was used to evaluate higher order cognitive ability associated with auditory processing. All the tests were played through a computer, the output of which was routed through a diagnostic audiometer at 40 dB SL [Ref average pure tone thresholds at 0.5, 1 and 2 k Hz (PTA)] to sound field speakers or
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TDH-39 earphones housed in MX-41/AR supra-aural ear cushions. The order in which these tests were administered was randomized to prevent any test order effect. In addition, for the monaural tests (SPIN-IE & DPT), half the participants were evaluated in the right ear first
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and half in the left ear first, to avoid an ear order effect. The procedure used to administer the test-battery is described below.
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The SPIN-IE was tested in each ear independently, with the participants having to
response sheet.
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repeat the words heard by them. The tester marked the responses as correct or wrong on a Each correct response was awarded a score of ‘1’ and each incorrect
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response was scored as ‘0’. Both raw and percentage scores were noted for each ear of the participants.
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The DCV test responses were obtained by instructing the participants to mark the syllables that were heard through headphones on a response sheet that had multiple choices.
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Double correct responses were calculated by awarding a score of ‘1’ if the responses in both
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ears were correct. A score of ‘0’ was given if the response was incorrect in either of the ears.
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The DPT was administered separately on each ear of the participants. The participants
were instructed to verbally report the pattern of length of the sounds heard. A correct response was given a score of ‘1’ and an incorrect response a score of ‘0’. The RAMST-IE was presented from a computer via an audiometer in two different
ways. Half the participants heard the material through two sound-field speakers, each placed at 450 azimuth at a distance of one meter from the head of the participant. The other half heard the material binaurally through headphones. The two different modes of presentations were used to check if there was any difference in the presentation mode. The output through both transducers was 40 dB SL (ref. PTA). The participants were asked to listen to each word-sequence and repeat the words heard in the same order as they were presented. The 13 Page 12 of 43
responses were noted by the evaluator on a scoring sheet. Both auditory memory and auditory sequencing were scored separately. While calculating auditory memory, a score of ‘1’ was given for each correctly repeated word. To calculate the auditory sequencing score, a
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score of ‘1’ was given only if the words were repeated in the correct order. Both auditory memory and sequencing scores were tabulated.
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Analyses
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Data obtained from the participants were tabulated and subjected to statistical analyses. The mean and standard deviation were calculated separately for data obtained for
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the four tests (SPIN-IE, DCV, DPT, & RAMST-IE) from the males and females in each age group. A mixed design ANOVA with ear as within participant variable and age, gender as
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between participant variables was carried out separately for SPIN-IE and DPT. Further, age
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Results
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memory and sequencing skills.
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and gender effects were investigated using ANOVA for DCV and MANOVA for auditory
The results of the four auditory processing tests (SPIN-IE, DCV, DPT, & RAMST-
IE) are provided, highlighting the effect of age, gender and ear / score within each test. Additionally, the percentage scores across the four tests are compared to determine the age related changes as a function of the auditory process or higher cognitive function that were evaluated.
Effect of gender, ear and age on auditory processes & auditory memory Speech in noise test (SPIN-IE) The mean and standard deviation of the scores obtained for SPIN-IE (Table 1) indicate that the scores in girls and boys increased with age in both ears. A mixed design 14 Page 13 of 43
repeated measure ANOVA, with ear as the within subject variable and age as well as gender as between group variables, showed no significant effect of ear on the scores [F(1, 268) = 0.11, p > 0.05]. Hence, for further analysis of the data, the scores of the left and right ears
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were combined. Between groups analysis showed a significant effect of age [F(4, 268) = 20.57, p < 0.01] but no significant effect of gender [F(1, 268) = 1.21, p < 0.01]. Further,
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there was no significant interaction among any of the variables.
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Pair-wise comparison, after Bonferroni correction (Figure 1) revealed a clear developmental trend with the performance of the 6-year-old children being significantly
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lower than that of all the older age groups. Likewise, the score of the 7-year-old and 8-year old children were significantly different from that of 9- and 10-year-old children.
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Insert Table 1
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Dichotic CV test (DCV)
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Insert Figure 1
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From the mean and standard deviation of the double correct scores for different age groups (Table 2), it can be observed that with increase in age the scores steadily increased. There was a high variability in the scores of 6 –year old children.
ANOVA indicated that
there was a significant main effect for age [F(4, 222) = 9.39, p < 0.01] but not for gender [F(1, 222) = 0.23, p > 0.05]. Further, a pair-wise comparison with Bonferroni correction (Figure 2) revealed that only the scores of the 6-year-old children were significantly lower than that of the other age groups. . Insert Table 2 Insert Figure 2.
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Duration Pattern Test (DPT) The descriptive statistics of the DPT (Table 3) shows that the mean scores for the 6year-old children were lower and had high variability when compared to the older children.
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As seen in the other tests, the performance of older children was better than that of younger children, with the performance of the boys and girls being similar. However, the mean scores
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of the left ear were better than that of the right ear in all age groups. A mixed design repeated
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measure ANOVA showed a significant main effect of age [F(1, 270) = 5.22, p < 0.05] as well as ear [F(4, 270) = 31.37, p < 0.01] but no significant difference between the scores of males
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and females [(1, 270) = 0.21, p > 0.05]. There was no two-way or three-way interaction. Pair-wise comparison with Bonferroni correction (Figure 3) highlighted that the
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scores of the 6-year-old children differed significantly from those of all other age groups. On the other hand, the performance of the 7-year-old children did not differ significantly from
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that of the 8-year-old children but it was significantly lower than that of the 9- and 10-year-
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old children. Likewise, the scores of the 8-year-old children did not differ significantly from
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that of the 9-year-old children but differed significantly from that of the 10-year-old children. Although the scores of the 10-year-old children were higher than that of the 9-year-old children, there was no significant difference. Insert Table 3
Insert Figure 3
It can be observed from Figure 3 and Table 3 that the variability was very high in the 6-year-old children. Hence, repeated measure ANOVA was performed after eliminating the data of the 6-year-old children. With the elimination of the 6-year-olds there continued to be
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a significant effect of age [F(3, 234) = 13.67, p > 0.05], however the ear effect that was present earlier disappeared [F(1, 234) = 2.32, p > 0.05].
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Revised Auditory Memory and Sequencing Test in Indian-English (RAMST-IE) As half the participants were tested under headphones and the other half through
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loudspeakers, initially an independent sample t-test was carried out to compare the scores obtained through the two transducers. The results showed no significant difference between
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the two groups for the auditory memory scores [t(275) = 1.48, p > 0.05] as well as the auditory sequencing scores [t(275) = 0.39, p > 0.05]. Hence, the data of the two groups were
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combined for further analysis. The mean and standard deviation of the combined scores obtained on the RAMST-IE, in general tended to be higher with increase in age (Table 4).
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This can be observed for both auditory memory and sequencing scores. From Table 4 it is also evident that the mean memory scores were much higher than the mean sequencing
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scores. This pattern was constant across all the five age groups. MANOVA indicated the
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presence of a significant age effect for both memory [F(4, 272) = 11.74, p < 0.01] and
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sequencing [F(4, 272) = 6.46, p < 0.01] scores. Gender did not have a significant effect on memory [F(1, 272) = 1.95; p > 0.05] or sequencing scores [F(1, 272) = 0.73, p > 0.05]. Additionally, there was no significant interaction between age and gender for the memory scores [F(4, 272) = 2.25, p > 0.05] and for the sequencing scores [F(4, 272) = 0.1.82, p > 0.05].
Insert Table 4
Pair-wise comparisons with Bonferroni corrections were carried out to determine how the different age groups varied from each other (Figure 4a & 4b). It was observed that the mean auditory memory scores of the 6-year-old children were significantly lower than that of the 8-, 9- and 10-year-old children.
Similarly, the 7-year-old and 8-year-old children
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performed significantly poorer than the 9- and 10-year-old children.
For the auditory
sequencing scores, the younger children (6-, 7-, & 8-year-olds) performed significantly poorer than the older children (9- & 10-year-olds). However, the sequencing scores were not
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significantly different among the younger or among the older children.
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Insert Figures 4a & 4b.
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Insert Table 5 Developmental trends for different tests
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The mean raw scored of the performance of the five age groups on the four tests (SPIN-IE, DCV, DPT, & RAMST-IE) were converted to percentage. The percentage was It can be observed from Figure 5 that
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calculated as the maximum scores of each test varied.
auditory sequencing was the most difficult task and understanding speech in noise was the
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easiest task for children in most of the age groups. A non-linear increase in performance,
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with a steep change from 6 to 7 years followed by a relatively gradual increase after 7 years
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of age, was observed for the scores of all the tests except auditory memory and sequencing. Compared to the other tests, the auditory memory and sequencing abilities showed lesser enhancement in scores with increase in age. SPIN-IE was the only test where the children did not have a steady increase in performance with increase in age. While the scores of most of the tests showed a plateau after 9 years of age, the scores of the DPT continued to increase till 10 years of age, though the pair-wise comparison did not show a statistically significant difference. The scores of DCV test showed a plateau after 8 years of age but the percentage scores were lesser than that of SPIN-IE. Insert Figure 5.
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Thus, the results indicated that depending on the test (SPIN-IE, DCV, DPT & RAMST-IE), the performance of children of different ages differed.
No significant
difference was observed between the performance of the 7- and 8-year-old children as well as
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the 9- and 10-year-old children on any of the tests. This is evident from Table 5 and Figure 5 that provide a summary of the significance of difference in the performance of the five age
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groups for each of the tests.
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Discussion
The findings of the study indicate that the performance of children on auditory
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processing or higher cognitive functioning tests increase with age.
The gender of the
participants was found to have no effect on the test performance. Additionally, there was no This indicates that auditory
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interaction of gender with age or ear for any of the tests.
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processing is similar in boys and girls aged 6 to 10 years. Thus, it can be construed that for clinical purposes, separate norms for males and females are unnecessary. Earlier studies have
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also reported of no gender differences in tests for auditory processing or higher cognitive functioning. These tests include speech-in-noise [12], DCV [34], DPT [35] as well as auditory memory and sequencing [36-38]. Neuroimaging studies of the brain of girls and boys have documented structural differences in the volume of the brain [39]. It can be construed that the structural changes reported in the brain of males and females are not significant enough to result in differences in auditory processing abilities. The performance across the two ears, evaluated for DPT and SPIN-IE, were found to be alike. Similar to the present study, the results of earlier investigations [18, 32] showed the absence of an ear effect for DPT. However, the ear effect has not been reported for speech perception in noise by the majority of the investigators who have studied this aspect. 19 Page 18 of 43
Findings regarding the age of the participants, in the current study revealed that most of the tests can be administered on children as young as 6 years of age. In general, the 6 year old children performed significantly poorer than the older age groups in most of the tests. An
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exception to this was their performance in the RAMST-IE. Additionally, it was observed that the 7 year old children did not differ significantly from the older children, especially from the
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adjacent older group. This indicates that the change in performance was very gradual from 7 to 8 years. However, there continued to be a significant increase in performance as the
Although there was no significant difference between the
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Table 5 and Figure 5.
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children grew older. The growth in performance varied from test to test, as can be seen in
performances of 9 and 10 year old children, the scores did not show a plateau, especially for
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DPT. Thus, the study highlights that age related changes continue even in the older age groups that were evaluated. The general increase in performance with age, observed in all
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the tests, substantiates the need to obtain age appropriate normative data.
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The results obtained in the study are similar to those reported in literature earlier. The
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effect of age has been demonstrated for the speech-in-noise test [40, 41], DCV test [12, 42] , DPT [18, 43] as well as auditory memory and sequencing test [37, 38, 44]. Although a direct comparison across studies is difficult as the age ranges studied and the stimuli used vary from study to study, the consensus is that performance on auditory processing tests improves with age. The findings of the present study indicate that although the auditory processes that were studied do not improve significantly in children from 9;11 years to 10;11 years, a marginal improvement was seen. These results reinforce the consensus that the auditory processing is not mature till 11 years of age. The age related changes in performance have been attributed to morphological changes that occur in the central auditory pathway. Luders, Thompson and Toga [45] observed an increase in the thickness of the corpus callosum in children in the age range of 5 20 Page 19 of 43
to 18 years and ascribed it to an increase in myelinated fibers. Based on a longitudinal MRI study of the brain in children aged 4 to 20 years, Giedd et al. [46] reported an increase in white matter and gray matter of the cortex in the preadolescent years. They further observed
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that increase in gray matter in the temporal lobe was non-linear and region-specific. In the current study, with increase in age, non-linear improvement in auditory processing was
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observed. Thus, it can be inferred that the age related structural changes result in age related changes in processing of auditory signals. Investigations correlating neuroimaging findings Recommendation to
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with results of audiological tests are required to corroborate this.
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conduct auditory processing tests only in children older than 7 years has led researchers to rarely provide auditory processing test norms for children younger than 7 years of age.
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ASHA [22] does not advocate testing auditory processing in children having a mental age below 7 years as they are likely to find the task difficult, thereby affecting the test results.
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Similarly, as per the AAA [47] guidelines for the ‘Diagnosis, Treatment and Management of
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Children and Adults with Central Auditory’, auditory processing tests are recommended to be carried out on those with a “minimum developmental age of seven or eight years, or a level of
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cognitive functioning that is consistent with this age range” (pp 14). However, from the findings of the present study, it is evident that it is possible to carry out certain auditory processing tests (SPIN-IE , DCV and RAMST-IE) on children as young as 6 years of age. Despite the 6 year old children obtaining significantly poorer scores than older children on most of these tests, the variability in performance was similar or less than that obtained by the older children for these three tests. As the variability in performance in this age group was not very large, the normative data obtained on them can be utilized usefully to make early diagnosis of the condition. Unlike most studies reported in literature, Stollman, Neijenhuis et al. [12], in a study on Dutch children, also demonstrated that tests for auditory processing can be conducted on children as young as 4 years of age.
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While the 6-year-old children in the current study were able to carry out most of the tests, the results indicate that it is difficult to administer DPT in this age group. It was observed that on this test, only two children obtained scores greater than 21, while 6 obtained
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scores between 10 and 20 and the remaining got scores of 0. The response mode used in the present study required linguistic labeling of the pattern that was heard. This probably made
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the task difficult as it tapped temporal processing as well as inter-hemispheric functioning. It has been reported that the functional development of inter-hemispheric connection undergoes
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a significant change between 6 to 8 years of age [48]. Thus, DPT requiring verbal responses
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is not a good test to assess temporal processing in 6-year-old children. It needs to be investigated if the performance would be better for humming responses.
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Double correct scores on DCV also showed large variability suggesting that binaural integration skills are difficult for 6- year old children.
DCV again taps the functioning of
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both the hemispheres as well as interhemispheric connections. The results obtained on
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double correct scores of DCV substantiates that there is a difference in the maturation rate of The single correct scores were not
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corpus callosum within children of this age group.
considered for analysis in this study, however it was observed that there was not much variability for single correct scores of 6 year old children. Hence it is suggested that while interpreting scores of 6 year old children on DCV, single correct scores can be used reliably but the double correct scores need to be interpreted with caution. Thus, in the present study, the comparison of performance of the children indicated
that auditory closure and monaural separation abilities, assessed by SPIN-IE, is developed early in childhood and stabilizes by 9 years of age. However, for DPT, the relatively poorer performance seen in the younger age group could either be on account of temporal ordering being developed later or due to immature corpus callosum. The latter would have resulted in the children that have difficulty in labeling the tones heard by them. The former can be 22 Page 21 of 43
confirmed only by evaluating DPT using humming responses. The results of DCV test suggest that auditory capacity to integrate stimuli heard in the two ears is very poor in 6-yearold children and reaches a plateau by 9 years of age. It is not clear whether poor auditory
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integration is due to immature auditory system or due to immature cognitive functioning. The performance of the children on the RAMST-IE varied depending on whether
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memory or sequencing abilities were assessed. In general it was observed that children in all
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age groups performed better when the ‘memory’ scores were calculated compared to when ‘sequencing’ scores were calculated. This can be attributed to the difficulty of the tasks. In
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the latter scoring procedure, the children were required to not only remember the words but also the correct sequence, while in the former scoring procedure they were not required to Although there were differences in the scores for
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remember the order of the stimuli.
‘memory’ and ‘sequencing’, both types of scores improved with increase in age. For the
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memory scores, the younger three age groups did not differ from those in the adjacent age
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groups (i.e. 6 year olds did not differ from the 7 year olds and the 7 year olds did not differ
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from the 8 year olds). Likewise, the oldest two age groups did not differ from each other. An almost similar trend was seen for the sequencing scores also. In general it can be noted that in the younger (6 to 8 year olds) and older age groups (9 to 10 year olds), the growth in auditory memory and sequencing was more gradual. However, it was more rapid between 8 to 9 years of age (Table 5).
The findings of auditory memory and sequencing are similar to what has been
reported in the literature. Gathercole et al. [37] also observed a significant age effect for auditory memory in children aged 4 years to 15 years using word, digit and non-word tasks. Similarly, Devi et al. [36] reported an increase in auditory memory with increase in age on an auditory memory and sequencing test in English, in children aged 6 to 12 years. Their results indicated that auditory memory scores increased with an advance in age up to ten years, after 23 Page 22 of 43
which a plateau was obtained. In a similar manner, Yathiraj and Vijayalakshmi [38] also found a significant age effect on a Kannada auditory memory and sequencing test in children aged 5 to 11 years. A significant difference was observed between each of the seven age
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groups. From the findings of the present study, it can be inferred that performance on all four
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tests that were evaluated (SPIN-IE, DCV, DPT & RAMST-IE) did improve with age.
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However, the rate at which the changes that took place varied from test to test. While certain tests had a steep increase in scores with increase in age (DCV & DPT) others had a gradual
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increase with age (RAMST-IE & SPIN-IE). Thus, it can be construed that different auditory processes have different rates of development, which is a reflection of the development of the
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different areas controlling the processes.
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Conclusion
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The present study was carried out with the aim to determine age related changes on a battery of four auditory processing tests (SPIN-IE, DCV, DPT and RAMST-IE) in 280
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typically developing children aged 6 to 10 years. The tests tapped auditory closure or monaural separation, binaural auditory integration abilities, temporal processing abilities as well as auditory memory and sequencing abilities. The study also determined the effect of gender for each of the tests. Ear effect was computed for the monaural tests that were evaluated (SPIN-IE & DPT). Analyses of the data showed that the older children performed better than the younger children. Although age had an effect on the results of all the tests, the rate of improvement in performance varied across the tests. A non-linear growth in performance with increase in age was observed for all four tests that were administered. The results indicated that the assessment of auditory processing abilities can be carried out on children as young as 6 years. The 6-year-old children could be tested using all the tests
24 Page 23 of 43
except DPT. While children aged 7 years and above could perform the DPT, those aged 6 years found the task too difficult and hence it is recommended that it should not be included in the test battery for children below 7 years of age. While evaluating 6 year children on
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DCV, double correct scores need to be interpreted with caution. Further, there was no significant difference between the performance of boys and girls. The performance in the
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two monaural tests (SPIN-IE & DPT) was similar in the right and left ears.
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Acknowledgements
This study is an outcome of a research project funded by the All India Institute of
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Speech and Hearing, Mysore. The All India Institute of Speech and Hearing, Mysore and Bharati Vidyapeeth Deemed University, Pune are acknowledged for providing the facilities to
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carry out the project. The contribution of Ms. Muthuselvi T., research officer in the project, is
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collected data at Pune.
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highly appreciated. Mr. Swarup Mishra and Ms. Aparna Oak are acknowledged for having
References
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Dev. 70(5)(1999):1082-97. [45] E. Luders, P.M. Thompson, A.W. Toga. The development of the corpus callosum in the healthy human brain. The Journal of Neuroscience. 30(33)(2010):10985-90. [46] J.N. Giedd, J. Blumenthal, N.O. Jeffries, F.X. Castellanos, H. Liu, A. Zijdenbos, et al. Brain development during childhood and adolescence: a longitudinal MRI study. Nat Neurosci. 2(10)(1999):861-3. [47] F.E. Musiek, J.A. Baran, T.J. Bellis, G.D. Chermak, J.W. Hall, R.W. Keith, et al. Guidelines for the diagnosis, treatment and management of children and adults with central auditory processing disorder. American Academy of Audiology. (2010). [48] M.T. Banich, W.S. Brown. A life-span perspective on interaction between the cerebral hemispheres. Developmental Neuropsychology. 18(2000):1-10.
Annexure 1
Sample of Test Material used for the study
Insert Figure A Insert Figure B Insert Figure C
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Insert Table A
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Table 1: Mean and SD scores for SPIN-IE Right ear
Left ear
Age in Years M
F
T
M
F
T
15.37 16.27 14.72
15.42
SD
4.09
3.96
3.91
4.08
3.86
4.00
18.41 18.90 18.20
SD
3.53
7 3.87
4.11
3.75
3.92
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3.25
18.56
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Mean 18.54 18.27
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Mean 16.56 14.41 6
Mean 18.07 17.27
17.66 17.53 17.53
17.53
SD
3.27
3.58
3.52
3.01
3.46
3.76
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8
Mean 21.34 21.06
21.20 21.44 20.12
20.76
SD
2.08
2.44
9 2.27
M
1.87
1.84
2.77
Mean 19.50 20. 63 19.81 19.50 20. 34 19.95 10 5.05
3.37
4.21
4.81
3.85
4.30
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SD
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Note. M = Males; F = Females; T = Males + Females
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Maximum possible score on SPIN-IE = 25
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Table 2: Mean and SD of the double correct scores on dichotic CV test across the age groups Double correct score Age in years T
Mean
5.7
5.27
5.46
SD
6.54
5.54
5.92
Mean
10.51 9.68
10.11
SD
5.19
4.92
Mean
11.96 12.60 12.28
SD
5.85
Mean
14.34 13.74 14.03
SD
5.81
6
4.66
8
Mean 10
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6.56
6.32
13.39 12.78 13.06 5.87
5.16
5.46
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SD
6.85
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9
7.28
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F
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Note. M = Males; F = Females; T = Males + Females
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Maximum possible single / double correct score = 30
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Table 3: Mean and SD of scores obtained for the Duration Pattern Test Right ear
Left ear
Age in years F
T
M
F
T
Mean
6.66
4.73
5.60
7.27
5. 54
6.32
SD
6.76
3.91
5.40
7.45
4.90
6.15
Mean
11.03 13.48 12.21 11.54 13.48 12.48
SD
5.67
Mean
15.90 14.20 15.05 15.66 15.16 15.41
SD
6.19
Mean
17.06 17.19 17.13 17.24 17.35 17.30
SD
4.23
Mean
19.85 19.28 19.55 20.82 18.96 19.83
SD
6.10
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6
7 7.34
8
9
M
5.95
7.47
6.81
7.05
6.48
7.06
3.46
6.43
7.11
7.28
6.72
5.60
6.90
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10
7.27
6.75
8.16
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7.26
5.80
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8.71
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Note. M = Males; F = Females; T = Males + Females
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Maximum possible duration pattern score = 30
31 Page 30 of 43
Table 4: Mean and SD of scores obtained for auditory memory and sequencing
Memory
Sequencing
Age in years
9
T
Mean
50.27 51.82 50.95 33.68 37.83 35.49
SD
8.97
Mean
49.41 55.97 52.80 39.23 34.24 36.82
SD
8.65
Mean
58.26 54.2
SD
11.95 11.85 11.98 12.83 11.03 12.06
Mean
60.97 61.66 61.3
SD
13.32 6.03
Mean
59.77 63.78 61.71 43.63 47.68 45.59
SD
10.03 12.41 11.32 12.06 16.78 14.54
8.52
10.97 7.91
9.46
7.39
8.61
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8.09
10.50 9.59
10.27
56.23 40.70 36.40 38.55
44.16 41.62 42.93
10.37 15.52 10.10 13.14
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M
7
T
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F
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Note. M = Males; F = Females; T = Males + Females;
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Maximum possible memory score = 118; Maximum possible sequence score = 118.
32 Page 31 of 43
Table 5: Summary of the effect of age of the participants on the four tests (SPIN-IE, DCV, DPT & RAMST-IE) RAMST-IE -
RAMST-IE -
Memory
Sequencing
7
8
9
10
7
9
10
7
6
**
NS
**
**
** ** ** ** ** ** **
**
NS
NS
**
NS
**
**
8 9
NS
9
10
**
*
NS
NS
8
NS
**
**
NS
**
NS
NS
8
9
** **
10
7
8
9
10
**
NS
NS
**
**
NS
**
NS
**
**
**
*
**
** ** NS
NS
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NS
7
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7
8
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DPT#
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DCV – DC
Age
SPIN-IE #
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Note. ** = p < 0.01; * = p < 0.05; NS = Not significant; # Average of left and right ears
33 Page 32 of 43
Table A. Sample of the word sequences of RAMST-IE
Rose Rope Shout Skirt Tap Sing
Stick Pull Run Head Plate
Cake Door Sky Cloud
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Car Chips Fast Rich Bus Rat
Mouth Flag Duck
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Dog Home Joy Hide Wright Class
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Stimuli
Soup Bring
Pray
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Word Sequence 3-word 4-word 5-word 6-word 7-word 8-word
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Captions for Figures Fig.1: Pair-wise comparison of age effect on SPIN-IE score
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Fig 3: Pair-wise comparison of age effect on Duration Pattern Test
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Fig2: Pair-wise comparison of age effect on DCV-DC score
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Fig 4: Pair-wise comparison of age effect on auditory memory (4a) and auditory sequencing (4b)
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Fig.5: Mean percentage scores of the different tests (SPIN-IE, DCV, DPT, RAMST-
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IE)
Fig A: Sample SPIN-IE with speech (bird, grapes, step, cloud) in upper track and
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noise in lower track, with both tracks being directed to one channel / ear
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Fig B: Sample waveform of DCV
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Fig C: Sample waveform of DPT
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