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Intellectual efficiency of children with unilateral hearing loss
International Journal of Pediatric Otorhinolaryngology (2006) 70, 1529—1532
www.elsevier.com/locate/ijporl
Intellectual efficiency of children with unilateral hearing loss Antoni Niedzielski *, Ewa Humeniuk, Przemysław Błaziak, ˙yna Gwizda Graz Medical University, Department of Clinical Psychology, Szkolna 18, 20-024 Lublin, Poland Received 6 December 2005; received in revised form 20 February 2006; accepted 20 February 2006
KEYWORDS Unilateral hearing loss; D. Wechsler Intelligence Scale; Intellectual development; Children
Summary Objective: The aim of our study was to observe the consequences of unilateral hearing loss with regard to intellectual functioning and development of children. Methods: The studies were conducted on the group of 64 children (42 boys and 22 girls) aged 6—16 years with left- or right-sided hearing loss using D. Wechsler Intelligence Scale for Children (WISC). Results: Children with right-sided hearing loss had a limited range of concepts, lower capability of learning verbal material and logical reasoning, abstract thinking and classifying. Left-sided hearing loss caused deterioration of intellectual abilities within non-verbal intelligence. Such a children had poorer abilities for analyzing, synthesizing and visual memory, worse spatial imagination and visual coordination. Conclusions: The examined children with unilateral hearing loss achieved the intelligence quotient on the average level in D. Wechsler Intelligence Scale. The side of hearing loss has a significant influence on the development of individual intellectual functions. # 2006 Published by Elsevier Ireland Ltd.
1. Introduction Unilateral hearing loss is mainly treated as the disorder of directional hearing and does not arouse a major interest among the persons dealing with this problem. However, the analysis of the consequences of unilateral hearing loss, particularly in the context of studies on functional asymmetry of hemispheres * Corresponding author. Tel.: +48 81 7405805 E-mail address: [email protected] (A. Niedzielski).
and in the field of intellectual development, may turn out to be very interesting. Knowledge of functional asymmetry indicates that the speech perception centres are usually localized in the left hemisphere and the perception is connected with the opposite ear [1]. It means that the right ear is dominating in the perception of sounds of the speech. This has a confirmation in Kimura’s studies with application of the dichotic listening technique. They imply that there is a prevalence of verbal material perception by right ear and the prevalence
0165-5876/$ — see front matter # 2006 Published by Elsevier Ireland Ltd. doi:10.1016/j.ijporl.2006.02.011
1530
A. Niedzielski et al.
of left-ear perception of musical tones, environmental sounds and emotional contents [2,3]. Normal functioning of sense organs facilitates the contact with the environment and is a basic factor for speech development and forming of intellectual efficiency in children. When any of the senses gets impaired there is a breaking or disorder of information contact. The children with impaired hearing are in such a situation. According to some studies, the limited supply of information resulting from the impairment of the hearing organ causes a hazardous situations to child’s correct intellectual development [4]. The survey of the studies on intelligence of deaf person and whose with impaired hearing reveals different opinions concerning this subject. Taking into account their intellectual abilities they are more or less retarded in relation to normally hearing population at the same age, as some of the researchers claim [4—6]. Nevertheless, other authors state that the deaf or those with hearing loss have a similar level of intellectual development as the hearing people [7]. In the present study we state that hearing loss and the side of this impairment has a specific influence on intellectual development of a child. The objective of our study was to observe the consequences of unilateral hearing loss in relation to development and intellectual functioning of children.
2. Materials and methods The examined group included 64 right-handed pediatric patients of the Audiologic Outpatients Clinic of the Department of Paediatric Otolaryngology, Phoniatry and Audiology of the Children’s University Hospital in Lublin in years 2003—2004. The group consisted of 42 males and 22 females aged 6— 16 years suffering from unilateral perceptive hearing loss above the level of 90 dB. The mean age of the children with right- and left-sided hearing loss was respectively 12.54 and 10.09) (Table 1). Rightsided hearing loss was more often and concerned
mainly boys. The most common causes of hearing loss in the examined group were past viral infections (41 cases and among them 21 with mumps history). Seven cases of hearing impairment was the consequence of mechanical trauma. In other cases the etiology remained unclear. The children with congenital hearing loss and without abilities of verbal communication were excluded from our study. The mean period of time from the occurance of hearing loss to the moment of inclusion to our study was 3.5 years. The study was performed using Wechsler Intelligence Scale for Children-Revised (WISC-R). This scale consists of two subtests: verbal (including: information, comprehension, similarities, arithmetic, vocabulary) and performance (including: picture completion, picture arrangement, bloc design, object assembly, coding). The individual examinations were always performed in the same conditions by the same researchers. The status consent was obtained from the Bioethical Committee.
3. Results Basing on the procedure of t-Student test, calculations were made on the significance of differences between the mean intelligence quotients achieved by a group of children with left- and right-sided hearing loss. The examined children with left- and right-sided hearing loss achieved intelligence quotient on the average level according to the full scale of Wechsler Intelligence Scale. The conducted studies and their statistical analysis revealed that the side of hearing impairment has a significant influence on the intellectual skills in children with hearing loss. According to verbal subtest, statistically significantly poorer
Table 1 Number of children with right- and left-sided hearing loss Right-sided receptive hearing loss
Left-sided receptive hearing loss
Girls Boys
14 25
8 17
Total
39
25
Fig. 1 The differences of mean intelligence quotients of children with the right- and left-sided hearing loss in the Wechsler Intelligence Scale.
Intellectual efficiency of children with unilateral hearing loss
1531
with left-sided hearing impairment and this is particularly revealed by subtests: block design and object assembly (the statistically significant difference on the level p < 0.05). It means that these children as compared to the children with rightsided hearing impairment have poorer abilities for analyzing, synthesizing, visual memory, poorer spatial imagination and visual-motor coordination (Fig. 3).
4. Discussion Fig. 2 The differences in mean values of intelligence quotient in children with right- and left-sided hearing loss according to Wechsler Intelligence Scale.
results are achieved by children with right-sided hearing loss ( p < 0.02). The side of hearing impairment does not seem to have so significant influence on the results of the intelligence quotient according to performance subtest (Fig. 1). Negative influence of right-sided hearing loss on verbal intelligence manifested particularly in the subtests of similarities, vocabulary (statistically significant difference on the level p < 0.01) and comprehension (statistically significant difference on the level p < 0.05). It means that the children with right-sided hearing loss in relation to children with left-sided hearing loss have a smaller range of concepts, poorer skills for learning verbal material and smaller abilities to use the acquired knowledge in everyday situations. Lower results in the sub-test of similarities may reveal as a poorer ability of logical thinking, abstract thinking and classifying (Fig. 2). According to non-verbal scale of Wechsler Intelligence Scale, poorer results are achieved by children
Fig. 3 The differences in mean values of intelligence quotient of children with right and left-sided hearing loss according to Wechsler Intelligence Scale.
The studies and observations of children with impaired hearing indicate that their general intelligence level does not differ from the intelligence of children with normal hearing. A significant retardation of intellectual development in this group is relatively rare, while a lower level of development of some selective intellectual functions is more frequent [5,8—10]. Our studies showed a similar tendency. The children in the examined group achieved intelligence quotient on the average level according to the full scale of Wechsler Intelligence Scale. However, there are clear differences in the development of individual intellectual functions depending on the side of the hearing loss. The right-sided perceptive hearing loss (the sounds from the right ear are analysed in the left hemisphere) results in the deterioration of the verbal intelligence level. The children with right-sided hearing loss have a poorer scope of concepts, lower ability to learn verbal material and logical thinking, abstract thinking and classifying. Those results confirm the opinion concerning the lower level of development within verbal intelligence in deaf children and children with hearing loss [6,11]. The studies carried out by Zweibel confirm that the main difference in intellectual development between the hearing and non-hearing children results from very low level of abstract thinking with domination of a specific experience [12]. Our studies confirmed that the left-sided perceptive hearing loss (the sounds from this ear are analysed in the right hemisphere) results in deterioration of intellectual skills within non-verbal intelligence. These children have lower abilities to analyse, synthesize and visual memory, poorer spatial imagination, worse visual-motor coordination. The majority of researches showed that the deaf children and children with hearing loss had a normal or even sometimes higher level of non-verbal intelligence [7]. However, recently it is more often discussed that the development of the deaf children and children with hearing loss is not equal also within non-verbal intelligence [13,14].
1532
5. Conclusions 1. The examined children with unilateral hearing loss achieve the intelligence quotient on the average level according to Wechsler Intelligence Scale. 2. The side of hearing impairment has a significant influence on the development of individual intellectual functions. 3. Children with right-sided hearing loss achieve a lower level of development within verbal intelligence. 4. Children with left-sided hearing loss achieve a lower level of skills within non-verbal intelligence.
References [1] Z.M. Kurkowski, Psychopedagogiczne i lingwistyczne konsekwencje głuchot jednostronnych, Audiofonologia 15 (1999) 209—215. [2] D. Kimura, Cerebral dominance and the perception of verbal stimuli, Can. J. Psychol. 15 (1961) 166—171. [3] D. Kimura, Functional asymmetry of the brain in dichotic listening, Cortex 3 (1967) 163—178. [4] O. Perier, Dziecko z uszkodzonym słuchem. Aspekty medyczne, wychowawcze, socjologiczne i psychologiczne, WSiP, Warszawa, 1992.
A. Niedzielski et al. [5] T.A. Allen, Study of the achievement patterns of hearing–— impaired students 1974—1984, in: A. Schildroth, M. Karchmer (Eds.), Deaf Children in America, College-Hill Press, San Diego, CA, 1986, pp. 161—206. [6] H.R. Myklebust, The Psychology of Deafness, New York and London, 1964. [7] J.Th. Snijders, N. Snijders-Oomen, Non-Verbal Intelligence Tests for Deaf and Hearing Subjects, Wolters-Noordhoff, Groningen, 1970. [8] K. Heiling, Deaf children development in a temporal perspective: academic achievement levels and social processes, Audiofonologia 29 (2001) 111—119. [9] F.H. Sisco, R.J. Anderson, Deaf children’s performance on WISC-R relative to hearing status of parents and child-rearing experiences, Am. Ann. Deaf. 126 (1978) 923—930. [10] J. Stachyra, Zdolnos´ci poznawcze i moz˙liwos´ci umysłowe ucznio ´w z uszkodzonym słuchem, Wydawnictwo UMCS, Lublin, 2001. [11] J.P. Braden, J.M. Hannah, Assessment of hearing — impaired and deaf children with the WISC-III clinical use and interpretation, in: A. Prifitera, D.H. Saklofske (Eds.), WISC — III Clinical Use Andinterpretation: Scientist — Practitioner Perspectives, San Diego, CA, USA, 1998. [12] A. Zweibel, D.M. Mertens, A comparation of intellectual structure in deaf and hearing children, Am. Ann. Deaf. 130 (1985) 27—31. [13] J. Smolen ´ska, Wpływ głuchoty na podstawowe funkcje zmysłowe, in: T. Gałkowski, J. Kaiser-Grodecka, J. Smolen ´ska (Eds.), Psychologia dziecka głuchego, PWN, Warszawa, 1988 . [14] V. Weichdold, H. Herka, Performance of hearing impaired children on Raven’s Coloured Progressive Matrices Test, Int. J. Pediatr. Otorhinolaryngol. 67 (2003) 1213—1217.
www.elsevier.com/locate/ijporl
Intellectual efficiency of children with unilateral hearing loss Antoni Niedzielski *, Ewa Humeniuk, Przemysław Błaziak, ˙yna Gwizda Graz Medical University, Department of Clinical Psychology, Szkolna 18, 20-024 Lublin, Poland Received 6 December 2005; received in revised form 20 February 2006; accepted 20 February 2006
KEYWORDS Unilateral hearing loss; D. Wechsler Intelligence Scale; Intellectual development; Children
Summary Objective: The aim of our study was to observe the consequences of unilateral hearing loss with regard to intellectual functioning and development of children. Methods: The studies were conducted on the group of 64 children (42 boys and 22 girls) aged 6—16 years with left- or right-sided hearing loss using D. Wechsler Intelligence Scale for Children (WISC). Results: Children with right-sided hearing loss had a limited range of concepts, lower capability of learning verbal material and logical reasoning, abstract thinking and classifying. Left-sided hearing loss caused deterioration of intellectual abilities within non-verbal intelligence. Such a children had poorer abilities for analyzing, synthesizing and visual memory, worse spatial imagination and visual coordination. Conclusions: The examined children with unilateral hearing loss achieved the intelligence quotient on the average level in D. Wechsler Intelligence Scale. The side of hearing loss has a significant influence on the development of individual intellectual functions. # 2006 Published by Elsevier Ireland Ltd.
1. Introduction Unilateral hearing loss is mainly treated as the disorder of directional hearing and does not arouse a major interest among the persons dealing with this problem. However, the analysis of the consequences of unilateral hearing loss, particularly in the context of studies on functional asymmetry of hemispheres * Corresponding author. Tel.: +48 81 7405805 E-mail address: [email protected] (A. Niedzielski).
and in the field of intellectual development, may turn out to be very interesting. Knowledge of functional asymmetry indicates that the speech perception centres are usually localized in the left hemisphere and the perception is connected with the opposite ear [1]. It means that the right ear is dominating in the perception of sounds of the speech. This has a confirmation in Kimura’s studies with application of the dichotic listening technique. They imply that there is a prevalence of verbal material perception by right ear and the prevalence
0165-5876/$ — see front matter # 2006 Published by Elsevier Ireland Ltd. doi:10.1016/j.ijporl.2006.02.011
1530
A. Niedzielski et al.
of left-ear perception of musical tones, environmental sounds and emotional contents [2,3]. Normal functioning of sense organs facilitates the contact with the environment and is a basic factor for speech development and forming of intellectual efficiency in children. When any of the senses gets impaired there is a breaking or disorder of information contact. The children with impaired hearing are in such a situation. According to some studies, the limited supply of information resulting from the impairment of the hearing organ causes a hazardous situations to child’s correct intellectual development [4]. The survey of the studies on intelligence of deaf person and whose with impaired hearing reveals different opinions concerning this subject. Taking into account their intellectual abilities they are more or less retarded in relation to normally hearing population at the same age, as some of the researchers claim [4—6]. Nevertheless, other authors state that the deaf or those with hearing loss have a similar level of intellectual development as the hearing people [7]. In the present study we state that hearing loss and the side of this impairment has a specific influence on intellectual development of a child. The objective of our study was to observe the consequences of unilateral hearing loss in relation to development and intellectual functioning of children.
2. Materials and methods The examined group included 64 right-handed pediatric patients of the Audiologic Outpatients Clinic of the Department of Paediatric Otolaryngology, Phoniatry and Audiology of the Children’s University Hospital in Lublin in years 2003—2004. The group consisted of 42 males and 22 females aged 6— 16 years suffering from unilateral perceptive hearing loss above the level of 90 dB. The mean age of the children with right- and left-sided hearing loss was respectively 12.54 and 10.09) (Table 1). Rightsided hearing loss was more often and concerned
mainly boys. The most common causes of hearing loss in the examined group were past viral infections (41 cases and among them 21 with mumps history). Seven cases of hearing impairment was the consequence of mechanical trauma. In other cases the etiology remained unclear. The children with congenital hearing loss and without abilities of verbal communication were excluded from our study. The mean period of time from the occurance of hearing loss to the moment of inclusion to our study was 3.5 years. The study was performed using Wechsler Intelligence Scale for Children-Revised (WISC-R). This scale consists of two subtests: verbal (including: information, comprehension, similarities, arithmetic, vocabulary) and performance (including: picture completion, picture arrangement, bloc design, object assembly, coding). The individual examinations were always performed in the same conditions by the same researchers. The status consent was obtained from the Bioethical Committee.
3. Results Basing on the procedure of t-Student test, calculations were made on the significance of differences between the mean intelligence quotients achieved by a group of children with left- and right-sided hearing loss. The examined children with left- and right-sided hearing loss achieved intelligence quotient on the average level according to the full scale of Wechsler Intelligence Scale. The conducted studies and their statistical analysis revealed that the side of hearing impairment has a significant influence on the intellectual skills in children with hearing loss. According to verbal subtest, statistically significantly poorer
Table 1 Number of children with right- and left-sided hearing loss Right-sided receptive hearing loss
Left-sided receptive hearing loss
Girls Boys
14 25
8 17
Total
39
25
Fig. 1 The differences of mean intelligence quotients of children with the right- and left-sided hearing loss in the Wechsler Intelligence Scale.
Intellectual efficiency of children with unilateral hearing loss
1531
with left-sided hearing impairment and this is particularly revealed by subtests: block design and object assembly (the statistically significant difference on the level p < 0.05). It means that these children as compared to the children with rightsided hearing impairment have poorer abilities for analyzing, synthesizing, visual memory, poorer spatial imagination and visual-motor coordination (Fig. 3).
4. Discussion Fig. 2 The differences in mean values of intelligence quotient in children with right- and left-sided hearing loss according to Wechsler Intelligence Scale.
results are achieved by children with right-sided hearing loss ( p < 0.02). The side of hearing impairment does not seem to have so significant influence on the results of the intelligence quotient according to performance subtest (Fig. 1). Negative influence of right-sided hearing loss on verbal intelligence manifested particularly in the subtests of similarities, vocabulary (statistically significant difference on the level p < 0.01) and comprehension (statistically significant difference on the level p < 0.05). It means that the children with right-sided hearing loss in relation to children with left-sided hearing loss have a smaller range of concepts, poorer skills for learning verbal material and smaller abilities to use the acquired knowledge in everyday situations. Lower results in the sub-test of similarities may reveal as a poorer ability of logical thinking, abstract thinking and classifying (Fig. 2). According to non-verbal scale of Wechsler Intelligence Scale, poorer results are achieved by children
Fig. 3 The differences in mean values of intelligence quotient of children with right and left-sided hearing loss according to Wechsler Intelligence Scale.
The studies and observations of children with impaired hearing indicate that their general intelligence level does not differ from the intelligence of children with normal hearing. A significant retardation of intellectual development in this group is relatively rare, while a lower level of development of some selective intellectual functions is more frequent [5,8—10]. Our studies showed a similar tendency. The children in the examined group achieved intelligence quotient on the average level according to the full scale of Wechsler Intelligence Scale. However, there are clear differences in the development of individual intellectual functions depending on the side of the hearing loss. The right-sided perceptive hearing loss (the sounds from the right ear are analysed in the left hemisphere) results in the deterioration of the verbal intelligence level. The children with right-sided hearing loss have a poorer scope of concepts, lower ability to learn verbal material and logical thinking, abstract thinking and classifying. Those results confirm the opinion concerning the lower level of development within verbal intelligence in deaf children and children with hearing loss [6,11]. The studies carried out by Zweibel confirm that the main difference in intellectual development between the hearing and non-hearing children results from very low level of abstract thinking with domination of a specific experience [12]. Our studies confirmed that the left-sided perceptive hearing loss (the sounds from this ear are analysed in the right hemisphere) results in deterioration of intellectual skills within non-verbal intelligence. These children have lower abilities to analyse, synthesize and visual memory, poorer spatial imagination, worse visual-motor coordination. The majority of researches showed that the deaf children and children with hearing loss had a normal or even sometimes higher level of non-verbal intelligence [7]. However, recently it is more often discussed that the development of the deaf children and children with hearing loss is not equal also within non-verbal intelligence [13,14].
1532
5. Conclusions 1. The examined children with unilateral hearing loss achieve the intelligence quotient on the average level according to Wechsler Intelligence Scale. 2. The side of hearing impairment has a significant influence on the development of individual intellectual functions. 3. Children with right-sided hearing loss achieve a lower level of development within verbal intelligence. 4. Children with left-sided hearing loss achieve a lower level of skills within non-verbal intelligence.
References [1] Z.M. Kurkowski, Psychopedagogiczne i lingwistyczne konsekwencje głuchot jednostronnych, Audiofonologia 15 (1999) 209—215. [2] D. Kimura, Cerebral dominance and the perception of verbal stimuli, Can. J. Psychol. 15 (1961) 166—171. [3] D. Kimura, Functional asymmetry of the brain in dichotic listening, Cortex 3 (1967) 163—178. [4] O. Perier, Dziecko z uszkodzonym słuchem. Aspekty medyczne, wychowawcze, socjologiczne i psychologiczne, WSiP, Warszawa, 1992.
A. Niedzielski et al. [5] T.A. Allen, Study of the achievement patterns of hearing–— impaired students 1974—1984, in: A. Schildroth, M. Karchmer (Eds.), Deaf Children in America, College-Hill Press, San Diego, CA, 1986, pp. 161—206. [6] H.R. Myklebust, The Psychology of Deafness, New York and London, 1964. [7] J.Th. Snijders, N. Snijders-Oomen, Non-Verbal Intelligence Tests for Deaf and Hearing Subjects, Wolters-Noordhoff, Groningen, 1970. [8] K. Heiling, Deaf children development in a temporal perspective: academic achievement levels and social processes, Audiofonologia 29 (2001) 111—119. [9] F.H. Sisco, R.J. Anderson, Deaf children’s performance on WISC-R relative to hearing status of parents and child-rearing experiences, Am. Ann. Deaf. 126 (1978) 923—930. [10] J. Stachyra, Zdolnos´ci poznawcze i moz˙liwos´ci umysłowe ucznio ´w z uszkodzonym słuchem, Wydawnictwo UMCS, Lublin, 2001. [11] J.P. Braden, J.M. Hannah, Assessment of hearing — impaired and deaf children with the WISC-III clinical use and interpretation, in: A. Prifitera, D.H. Saklofske (Eds.), WISC — III Clinical Use Andinterpretation: Scientist — Practitioner Perspectives, San Diego, CA, USA, 1998. [12] A. Zweibel, D.M. Mertens, A comparation of intellectual structure in deaf and hearing children, Am. Ann. Deaf. 130 (1985) 27—31. [13] J. Smolen ´ska, Wpływ głuchoty na podstawowe funkcje zmysłowe, in: T. Gałkowski, J. Kaiser-Grodecka, J. Smolen ´ska (Eds.), Psychologia dziecka głuchego, PWN, Warszawa, 1988 . [14] V. Weichdold, H. Herka, Performance of hearing impaired children on Raven’s Coloured Progressive Matrices Test, Int. J. Pediatr. Otorhinolaryngol. 67 (2003) 1213—1217.