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Cross-cultural adaptation and psychometric assessment of a Persian version of Proctor's developmental vocal assessment protocol: Description of Persian infant vocal development
Journal Pre-proof Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development Masoomeh Salmani, Reyhaneh Noruzi, Raheb Ghorbani, Majid Mirmohammadkhani, Maliheh Rafiyi, Bahareh Mansoori, Mona Simin Ghalam PII:
S0165-5876(19)30611-1
DOI:
https://doi.org/10.1016/j.ijporl.2019.109858
Reference:
PEDOT 109858
To appear in:
International Journal of Pediatric Otorhinolaryngology
Received Date: 21 September 2019 Revised Date:
21 December 2019
Accepted Date: 22 December 2019
Please cite this article as: M. Salmani, R. Noruzi, R. Ghorbani, M. Mirmohammadkhani, M. Rafiyi, B. Mansoori, M.S. Ghalam, Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development, International Journal of Pediatric Otorhinolaryngology, https://doi.org/10.1016/ j.ijporl.2019.109858. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. 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. © 2019 Published by Elsevier B.V.
Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development Masoomeh Salmani1, Reyhaneh Noruzi2*, Raheb Ghorbani3, Majid Mirmohammadkhani4, Maliheh Rafiyi5, Bahareh Mansoori5, Mona Simin Ghalam6 1
PhD of Speech and Language Therapy, Neuromuscular Rehabilitation Research center,
Semnan University of Medical Sciences, Semnan, Iran 2
Master of Speech and Language Therapy, Neuromuscular Rehabilitation Research center,
Semnan University of Medical Sciences, Semnan, Iran 3
PhD of Biostatistics, Social Determinants of Health Research Center, Semnan University of
Medical Scinces, Semnan, Iran. 4
MD, PhD in Epidemiology, Social Determinants of Health Research Center, Semnan
University of Medical Scinces, Semnan, Iran 5
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
6
Master of Occupational therapy, Neuromuscular Rehabilitation Research center, Semnan
University of Medical Sciences, Semnan, Iran
*
Corresponding author address: 5 km. of Damghan Road, Department of Speech and
Language Therapy, Rehabilitation Faculty, Semnan University of Medical Sciences, Semnan, Iran, +98 912 532 4398, [email protected]
1 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development
2 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Abstract Objectives: With increasing recognition of the importance of pre-linguistic vocalization, and early intervention for children, proper protocols play an important role in documenting infants' progress and effects of early interventional programs. This study aimed to translate Proctor’s Developmental Vocal Assessment Protocol into Persian, make cultural adaptations, assess Persian version of Developmental Vocal Assessment Protocol (P-DVAP)'s validity, internal consistency, and reliability, and provide a general perspective toward Persian infants' vocal behaviors. Methods: This study was mainly conducted in reference to Beaton’s guidelines included translation, synthesis, back-translation, expert committee review, & pretesting. Ten well-experienced speech and language therapists contributed in expert committee review. Mothers of 202 infants were interviewed by experienced speech and language therapists. Results: Expert committee pointed out some difficulties that parents might have responding to P-DVAP. Such difficulties were sorted out in the P-DVAP applied for psychometric analysis. The Content Validity Index and Content Validity Ratio of P-DVAP were above 0.9. In test-retest reliability, Kappa coefficient was 0.6 and as the measure of inter item consistency, Kuder-Richardson-20 for each stage ranged from 0.1 to 0.5. Parents of typical infants reported variations in crying, vegetative sounds, laughing, prosody changes, babbling, approximants of meaningful words, and consonant-vowel structures as the most common vocal behaviors. The number of vocal behaviors reported for preterm infants after corrected gestational age was fewer than those of typical full-term infants. Conclusion: The P-DVAP is a comprehensive, reliable, valid, simple and clear protocol for clinical evaluation of Persian infants’ vocal behaviors. Keywords: Vocalization, Assessment, Infant, Psychometrics, Child Development
3 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
1.1.
Introduction
Vocalizations in infants begin at birth, and early vocalizations are progressively refined into intelligible speech [1, 2]. There is a schedule for stages of vocal development during first year. Just after birth, the first vocal behaviors include crying and vegetative noises. Next 26 weeks, infants have Cooing, and Babbling as their significant vocal milestones. Reduplicated, variegated, and canonical babbling appear later [3]. These vocal milestones are associated with some specific vocal behaviors that appear to play role in connecting sound to meaning. These specific vocal behaviors include echolalia (an immediate imitation of some other speakers), jargon (long strings of unintelligible sounds with adult-like prosodic and intonational patterns), and Phonetically Consistent Form (speech-sound pattern with consistent prosodic form [4, 5]. Vocal behaviors are evidences of the connection between early babbling and later spoken language [5]. Including basic features of adult speech [5] and having relationship with early speech development [6] make infants’ vocal behaviors an interesting subject to be investigated indepth specially for infants who have risk factors such as hearing loss or cleft lip and palate [7, 8]. The most common assessment tool of infants’ vocal behaviors is parents’ proxy reports. The usual questionnaires for this aim include the chronological ages of vocal milestones defined by different studies [9-12]. In these tools, there are usually five stages and despite some differences, each advancing stage in these models is distinguished from previous stages by the addition of more advanced vocal behaviors. In spite of the values of infant vocal assessment, speech and language pathologists (SLPs) in Iran have access to very few valid measures to examine infant vocalizations, while values of such tools in the matter of the connections between early vocalization and later language development [13] and advantages of early identification and intervention [12] are undeniable. Oryadi-Zanjani [14] presented the Persian version of the Production of Infant Scale Evaluation (PRISE). While appropriate steps were taken to provide the cross-cultural adaptation of this instrument, the Persian version of the PRISE contained only 11 items and was presented specifically as an assessment tool to assist in the early diagnosis of hearing loss and evaluate the effectiveness of cochlear implants in infants with hearing loss [14]. This highlights the need for proxy-report instruments for a wider range of purposes in the assessment of early vocal behaviors in Persian infants. In the other hand, most instruments used for early vocal development assessment have been developed in English-speaking countries. If these instruments are simply translated and used clinically in different cultural and linguistic contexts, the validity of the tool may be
4 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
compromised [15, 16] and some concepts may be lost in translation. Adapted assessment tools for early vocal development should be equivalent to the original version in order to provide comparable opportunities to observe vocal behaviors [16, 17]. Therefore, before the original English versions of the vocal development questionnaires are used in non-English countries, the English versions should be adapted to minimize the systematic biases and maintain its content validity across cultures [17]. One of these vocal assessment tools is Developmental Vocal Assessment Protocol (DVAP) developed by Proctor in 1989 which examines early vocalizations from birth to age of 12 months in five stages (0-2, 2-4, 4-6, 6-10 and 10-12 months). Each stage encompasses a set of items to assess the presence of specific vocal behaviors. In addition, to supplement the report provided by caregivers, the vocal behaviors of infants could be directly observed during routine activities or through recording a sample of their vocalizations. Although the DVAP is not a norm-referenced assessment tool, it has guideline [6, 18] that makes it a proper tool to check infants’ changes during intervention or typical development and to investigate the need of vocal stimulation during intervention. The stage of vocal development is determined by identifying the highest stage at which there is the presence of at least one listed vocal behavior. If the marked stage matches the chronological age of the infant, vocal development is considered emerging and typical [19]. The DVAP has not been validated for any other languages however it has been used by researchers to make vocal checklist for their own studies [13]. Although, Proctor’s article has been cited by different English studies [20-22], authors could not find any validation process taken place on DVAP for English speaking countries. Probably Proctor’s work could be considered as a pioneer research in the matter of infant’s prelinguistic vocalization. The use of validated parental reports has been developed recently specially for infants and toddlers [13]. When the standardized evaluation cannot be implemented, parents' proxy reports are reliable enough to present valuable data on infant vocalization. Parental reports must be simple, easy to complete, quick, and systematic, which apply to DVAP. Therefore, it seems that this questionnaire is an optimal tool to be adapted for assessing the vocalizations of Persian infants. It is notable that this instrument does not rely on the infants' vocal behaviors as the main criterion to divide the developmental stages and uses chronological division instead, so that clinicians could complete the questionnaire more easily. The present study aimed to translate the original version of the DVAP into Persian, and to evaluate the validity and reliability of this adapted DVAP. Furthermore, through this study
5 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
we described the stages of early vocal development in Persian infants using the Persian Developmental Vocal Assessment Protocol (P-DVAP). 1.2.
Materials and Methods
The study protocol was approved by the Ethics Committee of [deleted for peer-review] (the name of the institute affiliated with the authors). The methodology used in the present study was based on guidelines for cross-cultural adaptation as proposed by Beaton and colleagues (2000) [17]. 1.2.1.
Step 1. Forward Translation
Based on the procedure outlines by Beaton and colleagues (2000) [17], the DVAP was initially forward-translated into Persian by two independent translators who were native Persian speakers (target language of the adaptation) and fluent in English as their second language. The translators were asked to note the difficulties and ambiguities in translation. Afterwards, the translations and the comments reported by the translators were reviewed by the first author in order to identify any ambiguous and challenging phrases and expressions from the original version. In addition, she identified any discrepancies between the two translated versions, particularly reflecting lexical choice and nuanced expressions in Persian. Following that, she moderated a discussion with the translators and the other team members in order to synthesize the two translated versions to produce a single, consensus-based translation in Persian. 1.2.2.
Step 2: Backward Translation
The consensus-based translation was back-translated into English by two independent translators who were blinded to the original version and did not have any role in the previous section. The purpose of the back-translation was to ensure that the forward translation into Persian accurately reflected the content of the original English version and to identify any conceptual errors in the translation [17]. 1.2.3.
Step 3: Pre-testing and Cognitive Interviewing
Following the back-translation and minor adjustments, according to the WHO’ recommendation [23], there was a pilot session, which an experienced SLP interviewed mothers of 10 infants from the target population and filled out the P-DVAP. The goal was to find out the difficulty, ambiguity, or any unacceptable words/phrases of the questionnaire. The SLP and each mother went through each item and asked mothers about special phrases, the responses that came to their mind with first confrontation and what each item was looking
6 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
for. The SLP kept time recording to estimate the amount of time that SLPs need to fill out PDVAP. A report was prepared and the research team looked at difficulties of the P-DVAP from mothers’ perspectives and reached consensus final translation. 1.2.4.
Step 4: Validity
The correspondence author invited 28 SLPs according to their resumes, research interest and work experience to be part of a panel to run content evaluation. Ten signed consent forms were returned. The panel included SLPs who had experiences in NICU, Early Intervention for different groups of infants (with cleft lip and palate or hearing loss), or speech and language intervention for children who had communicative skills at the level of pre-linguistic or emerging language (see table 1). In one session, hard copy of table 2 and the final Persian translation of DVAP was provided for each SLP and each panelist –independent of the others- was asked to rate each item of P-DVAP on clarity (well-written, and distinct concepts), simplicity (easily understandable in Persian), necessity (essential) and relevance (was each item related to the vocalization in infants). Please insert tables 1 & 2 here To calculate Content Validity Ratio (CVR), the present study used Lawshe’s model. First author pooled all responses and reported the percentage of experts who scored each item as essential (Figure 1) and result was interpreted using table 3. The Content Validity Index (CVI) was calculated too. In CVI, the number of panelists who chose score 3 or 4 for each item in the matter of relevancy was divided by the total number of panelists. Items with CVI of 0.78 or higher were considered as evidence of good content validity [24]. Please insert Table 3 Here Twelve infants were randomly chosen and re-evaluated 10 days after the first evaluation to estimate test-retest reliability. The inter-item consistency was calculated to find out the level of relationship among items. 1.2.5.
Step 5: Pre-testing of the P-DVAP
The next stage of the cross-cultural adaptation was to evaluate the P-DVAP in terms of potential clinical use with the target population [17]. The authors recruited Persian-speaking infants aged 0-12 months and their parents via convenience sampling from the available database of a health centre in Semnan city, Iran. Three hundred thirty two infants aged 0-12 months had been registered in the database. All registered families were invited to participate in the study by their own health advisors. In
7 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
total, 202 parents (59.9%) whose infants were aged 0-12 months agreed to participate and completed the first interview. During the first interview with mothers, different types of data were collected such as demographic information and infants’ developmental histories. The infants and their families came from Semnan city. The range of the number of family members was from three to five. All parents spoke Persian. It was quite challenging to find out reality of socioeconomic status (SES) through family income or parental occupation. However, maternal education as another index of SES [25] was more reliable to be reported. Table 4 shows the education level of the mothers and number of their infants in each age group. The mean ±SD age of the participating mothers was 28 years ± 5.7 years. Please insert table 4 here During the first interview, developmental history data were collected regarding hearing acuity, prematurity, presence of jaundice, head trauma, asphyxia, anoxia, and other birth and developmental defects. Hundred twenty nine full-term infants (63.9%) had no obvious signs of sensory, physical, and mental handicaps, without any history of jaundice, hypoxia and they all passed auditory screening test without any problem. The other 73 infants (36.1%) had some problem in their medical history (See table 5 for more details). Insert table 5 here please Health advisors provided reports of infants’ general development according to standardized version of Ages and Stages Questionnaire for Iranian children [26] and mothers’ mental health based on their routine evaluation at health centers. Health advisors confirmed that infants were in typical range of general development and their mothers did not have any specific mental health problem. The P-DVAP was filled out via face-to-face interviews with all participating mothers by two experienced SLPs, and the interviews were audio recorded to evaluate the accuracy of the collected data. The P-DVAP from the step 4 was completed with the assistance of the parents rather than the direct observation of the infant by the researchers. The examiners followed the English guideline. For instance, if an infant was aged 5 months, the SLP asked the items present in the third stage (4-6 months). Production of only one vocal behavior was necessary to show the infants vocalizations were as expected based on their age. If the infant did not express one of the listed behaviors in the stage 3, the SLP moved one stage back and investigated the items of the second stage. Likewise, if stage 2 vocal behavior was not present in parent report, first stage items would then be asked. 1.2.6.
Step 6: Statistical Analysis
8 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Data analysis was performed in SPSS version 24. The face and content validity of PDVAP was assessed based on the mean scores achieved by the rating of each item. In the matter of inter-item consistency of each stage, Kuder-Richardson 20 through the STATA-11 and for the test-retest reliability, Kappa as the measure of agreement through SPSS 24 were administered by an epidemiologist. 1.3.
Results
1.3.1.
Steps 1 to 4
The P-DVAP has been developed from the cross-cultural adaptation of the English version of the developmental vocal assessment protocol [12]. In the cross-cultural adaptation, some modifications were inevitable; however the number of the items in the English version remained the same in the Persian version. There are eight vowels in the DVAP (i, I, e, ʌ, u, U, o, a), while there are six vowels in the P-DVAP (i, e, u, o, a, â). It was rather difficult to find transparent, equivalent Persian substitutes for words such as ‘squeal’, ‘growls’, ‘fussing’, ‘grunting’, and ‘blowing raspberries’. To be able to transfer similar contents in the case of these specific words, the translators used native Persian phrases and in backward translation, it did not affect the English version. In pretesting and cognitive interviewing, mothers asked for some examples to be able to give a better response for some items (e.g., item five in stage five “prosodic counters to match intonation patterns”). Such items needed to be thoroughly explained to obtain reliable responses. If mothers still had problem with a specific item, the SLP provided videos to help mothers. Their answers were so close to what they had in their minds in first confrontation. Mothers recognized the concepts of items correctly and they did not need to do any rewording or rephrasing to be able to answer each item. Even some mothers showed some of their own infants’ videos to certify the presence of specific vocal behavior. The examiner needed three to six minutes to fill out P-DVAP for each mother. The need for different timing was the result of differences in the number of items in each stage and sometimes difficulty of some items. The expert panel suggested that some items be presented as complete sentences instead of using infinitives in their Persian structure, so that the items would be more comprehensible for Iranian SLPs and parents. In the matter of surface validity (clarity and simplicity of PDVAP) which is a part of content validity [27], 70-100% of the SLPs (N= 10) graded all the items 3 to 4. Therefore, the items in all of stages were clear regarding the use of Persian words, content, and structures and they were quite simple. CVR was equal to 0.9 and CVI was
9 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
equal to 0.98. As such, the content validity of the Persian adaptation was good according to Polit, Beck and Owen (2007) [24]. Test- retest was taken place on 12 infants; the Kappa as the measure of agreement was 0.6. This might be able to show that P-DVAP has moderate reliability according to Landis and Koch scale [28]. The Kuder-Richardson 20 coefficients as measure of inter-item consistency for stages one to five were 0.34, 0.16, 0.53, 0.54, and 0.08 respectively. 1.3.2.
Steps 5: Typical Infants
All infants showed matching vocal behaviors to their chronological age indicating typical development as it was expected since none of the infants (n=129) had any significant medical or family history for health, speech, and language problems. Table 5 shows the percentage of the mothers reporting each vocal behavior in their infants in P-DVAP. There were no missing responses in the present study because the examiner was responsible to check all items with mothers. Less than 50% of the mothers with full term typical infants reported all four behaviors across the five stages to be demonstrated in their infants. Behaviors included stage 3) increases in the number of consonants, stage 4) nonreduplicated consonant-vowel sequences and the first words, and stage 5) jargons, protowords, and phonetically consistent forms (Table 6). Please Insert Table 6 here It seems that the mothers were more confident about the non-speech sounds in their infants since crying and vegetative sounds were reported by more than 80% of the mothers, while speech vowels (item five in stage 1) were reported by 50% of mothers. In the second stage, the vocal behaviors associated with speech usage of consonant + vowel structures mainly “coo” and “goo” were observed by only 50% of the mothers. For non-speech sounds, however, more than 75% of the mothers reported a significant reduction in the crying of the infants, as well as the increased demonstration of pleasure sounds. The parental reports of vocal behaviors in the third stage did not follow the same patterns of the first and second stage. In this stage, some of vocal behaviors associated with actual speech were reported by approximately 90% of families, although reports some specific consonants (item 4) were still below 50%. Apparently, the items in the fourth stage were relatively challenging for the families since none of the items were reported by 100% of the mothers. However, canonical or reduplicated babbling as a significant vocal behavior was reported by 90% of the mothers. All items in stage 4 were focused on speech and language development. Difficulty in the
10 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
detection of speech sounds (consonants or vowels) by non-expert individuals might be the reason for parents not reporting behaviors associated with speech sounds in their infants. Over 80% of the mothers reported vocal behaviors corresponding to syllables and approximations of meaningful, single words in stage 5. However, changes in prosody, variegated babbling, and use of jargons were not commonly reported in this age range. 1.3.3.
Steps 5: Infants with Problems in their Past Medical History
According to table 7, preterm infants whose ages were corrected for gestational age had fewer numbers of vocal behavior compared with full term typical infants. It should be noticed that these preterm infants were recognized typical on their ASQ reports. Please Insert Table 7 here The other 10 infants with other types of past medical histories showed fewer numbers of vocal behaviors too. However the number of these infants was not enough to reach a confident result. 1.4.
Discussion
The present study described the initial stages of the cross-cultural adaptation of the DVAP for Persian infants. This was the first investigation regarding early vocal development in Persian infants aged 0-12 months. We adapted the original version of the instrument in terms of the cultural and linguistic environment in Persian clinical settings in accordance with the guidelines recommended for the process of cross-cultural adaptation by Beaton and colleagues (2000) [17]. Following these guidelines has practical advantages over a simple forward translation since it minimizes threats to the validity of the instrument due to inherent cultural and linguistic biases, thereby ensuring the cultural, linguistic, and conceptual equivalence between the original and adapted versions [15-17, 29]. Our findings suggested that the P-DVAP has good content validity, and moderate reliability. The cross-cultural adaptation of DVAP also provided an opportunity to investigate early vocal development in Persian infants for the first time. Vegetative sounds, crying, pleasure sounds, intonational encounters, laughter, canonical babbling, and word approximants were easily recognized vocal behaviors by the parents. This finding was in concert with the description of early vocal behaviors in English infants [9-12]. According to the results of the present study, it is not likely that Persian infants produce their first words around the age of 10 months. This finding supports the previous findings for the Persian children that the first words will be produced around 12 to 14 months [30] The similarity between what parents reported in the present study and the previous reports on English infants’ vocal behavior in addition to the moderate reliability in test-retest
11 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
can confirm that parents can reliably recognize milestones of infants’ vocal behaviors. This finding supports previous findings that parents are accurate observers of their infants vocal behavior [31]. They were more confident about some certain vocal behaviors when they were given videos or examples. This finding was in agreement with finding reported by Lyytinen and her colleagues (1996) who found concrete examples of vocal behaviors helped parents to recognize vocal behavior reliably. Preterm infants whose ages were corrected for gestational age showed fewer numbers of vocal behaviors compared with their typical age peers. This study did not look for the cause of such finding, however, Salerni and colleagues in 2007 analyzed mother-infant dyads and found out that in the conversations of mother-preterm babies, mothers were highly responsive and their preterm infants were not active during interaction [32]. Some vocal behaviors in P-DVAP such as that were only reported by 50% of the parents (ex. hearing the first words around 10 months) in the current research could be eliminated after further investigating of the questionnaire. It is recommended that further research be conducted in order to clarify the use of the P-DVAP in infants with cleft lip and palate, or those at risk for later communicative disorders. 1.5.
Limitations of the Study
The present study was only based on reports provided by parents. A comprehensive view of vocal behaviors in Persian infants could be achieved through an extended study covering clinical observations, and home videos, in conjunction with parental reports. A longitudinal study would help answer the question regarding the sufficiency of requiring only one behavior in a stage to document attainment of that stage. 1.6.
Conclusion
In the current research, DVAP was translated in accordance with international guidelines and validated by experienced Persian SLPs. According to the results, the P-DVAP is a valid, reliable, quick, useful measure to evaluate the vocal behaviors of infants based on their chronological age. 1.7.
Acknowledgments
Hereby, we extend our gratitude to Proctor [12] for the permission to adapt the developmental vocal assessment tool to Persian. We would like to thank Dr Jae Hyun Kim (a Lecturer in the Master of Speech and Language Pathology program in the Department of Linguistics, at the Macquarie University, Australia) for his contribution to the editing and writing of this manuscript, and the families who participated in the study. We are extremely grateful to the ---- for the financial support of this study (grant number: ---).
12 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
1.8.
Conflict of Interest: Authors declare that they have no conflict of interest.
13 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
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15
Table 1: Summary of Information regarding to Content Validity Panelists Speech and Language Pathologist
University Degree
Years’ experience
Employment setting
1
Master
9
NICU + clinic
2
Phd
6
Clinic + University
3
Phd
15
NICU + University Clinics
4
Master
16
Clinic
5
Master
8
Clinic
6
Master
28
Clinic
7
Bachelor
16
Clinic + Schools
8
Phd
6
Clinic + University
9
Master
6
Clinic
10
Master
16
Clinic + Schools
16
Table 2: The items included in the questionnaire to evaluate content validity of the P-DVAP
Clarity
Score Simplicity
Score Relevancy
It is 4 completely clear with proper writing. It is relatively 3 clear with proper writing.
It is quite 4 simple and Persian*.
It is relatively 2 clear and its writing needs to be corrected. It is not clear 1 and its writing is full of errors.
It is almost 2 simple with some English words It is 1 complex with English words.
It is largely 3 simple and Persian
It is completely related to the development of vocalization in infants. It is largely related to the development of vocalization in infants. It is slightly related to the development of vocalization in infants. It is not related to the development of vocalization in infants.
Score Necessity 4
It is quite 4 essential.
3
It is 3 relatively necessary.
2
It is useful.
1
It is not 1 necessary.
* In the information sheet, we asked the experts that questionnaire MUST be only in Persian not any modified English words.
Score
2
17
Table 3: Lawshe’s Model to Interpret CVR The number of panelists 5 6 7 8 9 10 15 20 25 30 35 40
The Minimum Level of Validity 0.99 0.99 0.99 0.75 0.78 0.62 0.49 0.42 0.37 0.33 0.31 0.29
18
Table 4: Maternal Education
Maternal Education
Total
Illiterate Primary Guidance school Diploma Bachelor Master and PhD
0-2+ 3 10 12 20 12 4 61
Infants Age Groups 2-4+ 4-6+ 6-10+ 5 2 5 1 5 10 5 1 1 5 8 22 4 7 14 3 5 3 23 28 55
10-12 2 2 2 15 12 2 35
Total 17 28 21 70 49 17 202
19
Table 5. Frequency of Infants according to their Past Medical History (PMH) Chronological Age 0-2 2-4 4-6 6-10 10-12 Without any problem 38 17 19 34 21 Jaundice 13 4 7 11 10 Jaundice + Preterm 5 0 1 0 1 PMH Preterm 3 1 1 10 3 Hearing Acuity Problem 1 0 0 0 0 * Complex Past Medical History 1 0 0 0 0 Hypoxia 0 1 0 0 0 Total 61 23 28 55 35 * This child was born preterm, with jaundice and problem to pass hearing screening test.
Total 129 45 7 18 1 1 1 202
20
Table 6: Summary of the Parental Responses on the P-DVAP (n= 129) Vocalization types
Parental reports
Number of Parents = 38
Yes1
No2
No. Stage 1: 0-2 months 1
Crying with sudden pitch shifts, extremely high pitch
81.6
18.4
2
Fussing or discomfort
73.7
26.3
3
Vegetative sounds (burps, sounds accompanying feeding)
97.4
2.6
4
Neutral sounds (grunts, sighs)
36.8
63.2
5
Vowel-like sounds: (/i/, /e/, /u/, /o/, /a/, /â /)
50
50
Yes1
No2
Number of Parents: 17 No. Stage 2: 2-4 months 1
Vowel sounds predominate, but a few consonants emerge (primarily velars and glottals)
58.8
41.2
2
Marked decrease in Crying (after 12 weeks)
82.4
17.6
3
Begins Consonants plus vowel; mostly "coo" and "goo"
52.9
47.1
4
Begins to produce pleasure sounds, such as "mmmmm"
76.5
23.5
1
No2
Number of Parents: 19
Yes
No. Stage 3: 4-6 months Consistent production of consonant-vowel (CV) (syllabic) 1 52.6 combinations
47.4
2
Imitation of sounds in back-and-forth babbling games with 89.5 others
10.5
3
More variations in vowel production
89.5
10.5
4
Number of consonant segments increases to include front 42.1 stops and nasals
57.9
5
Laughter emerges (around 16 weeks)
0.00
6
Front sounds begin to predominate, including blowing 94.7 "raspberries", bilabial trills (lip smacks)
5.3
7
Begins variation of intonational (pitch) contours, often 100 when playing alone with toys
0.00
8
Extreme pitch glides, such as yells, squeals, and low78.9 pitched growls
21.1
Yes1
No2
Number of Parents: 33
100
No. Stage 4: 6-10 months 1
Canonical, repetitive, or reduplicated babbling (CV or CVCV-like structure) begins to appear (/mama/, /dada/, and 90.9 /nʌnʌ /)
9.1
2
Consistent variation of intonational contours
75.8
24.2
3
Early non-reduplicated CV sequences appear
42.9
57.1
21
4
Parent may report hearing first word around 10 months
21.2
78.8
5
Utterances produced with stop consonant (p, b, t, d, are 75.8 most common)
24.2
6
Short exclamations such as "ooh!" begin to appear
75.8
24.2
1
No2
Number of Parents: 21
Yes
No. Stage 5: 10-12 months Variegated babbling (successive syllable not identical) 1 61.9 appears
38.1
2
Variety of CV and CVC combinations with sentence-like 81 intonation
19
3
Syllables other than CVs produced
85.7
14.3
4
Use of jargon, protowords, or phonetically consistent forms 47.6 emerges
52.4
5
Increased development of prosodic contours to match 52.4 intonation patterns of ambient language
47.6
6
Approximations of meaningful single words; phonological 90.5 processes may operate on word approximations
9.5
1 2
Infant shows the vocal behavior. Infant does not show the vocal behavior.
22
Table 7: Vocal Behaviors in Infants with Different Past Medical Histories
Participants
Number of Vocal
Full-Term Typical Infants (n = 129)
Full-Term Typical Infants with History
Preterm Infants (n = 18)
of Jaundice (n = 45)
Mean
SD
Mean
SD
Mean
SD
Stage I
3.4
1.08
3.7
0.95
2.7
1.16
Stage II
2.7
0.99
3.0
0.00
2.0
0.00
Stage III
6.6
1.26
5.7
1.89
5.0
0.00
Stage IV
3.8
1.28
3.7
1.42
2.4
2.01
Stage V
4.2
1.12
4.6
0.97
3.7
0.58
Behaviors
23
Figure 1: Lawshe’s Method to Calculate Content Validity (ne = number of panelists identifying an item essential; N = total number of expert panel)
S0165-5876(19)30611-1
DOI:
https://doi.org/10.1016/j.ijporl.2019.109858
Reference:
PEDOT 109858
To appear in:
International Journal of Pediatric Otorhinolaryngology
Received Date: 21 September 2019 Revised Date:
21 December 2019
Accepted Date: 22 December 2019
Please cite this article as: M. Salmani, R. Noruzi, R. Ghorbani, M. Mirmohammadkhani, M. Rafiyi, B. Mansoori, M.S. Ghalam, Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development, International Journal of Pediatric Otorhinolaryngology, https://doi.org/10.1016/ j.ijporl.2019.109858. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. 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. © 2019 Published by Elsevier B.V.
Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development Masoomeh Salmani1, Reyhaneh Noruzi2*, Raheb Ghorbani3, Majid Mirmohammadkhani4, Maliheh Rafiyi5, Bahareh Mansoori5, Mona Simin Ghalam6 1
PhD of Speech and Language Therapy, Neuromuscular Rehabilitation Research center,
Semnan University of Medical Sciences, Semnan, Iran 2
Master of Speech and Language Therapy, Neuromuscular Rehabilitation Research center,
Semnan University of Medical Sciences, Semnan, Iran 3
PhD of Biostatistics, Social Determinants of Health Research Center, Semnan University of
Medical Scinces, Semnan, Iran. 4
MD, PhD in Epidemiology, Social Determinants of Health Research Center, Semnan
University of Medical Scinces, Semnan, Iran 5
Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
6
Master of Occupational therapy, Neuromuscular Rehabilitation Research center, Semnan
University of Medical Sciences, Semnan, Iran
*
Corresponding author address: 5 km. of Damghan Road, Department of Speech and
Language Therapy, Rehabilitation Faculty, Semnan University of Medical Sciences, Semnan, Iran, +98 912 532 4398, [email protected]
1 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Cross-cultural Adaptation and Psychometric Assessment of a Persian Version of Proctor's Developmental Vocal Assessment Protocol: Description of Persian Infant Vocal Development
2 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Abstract Objectives: With increasing recognition of the importance of pre-linguistic vocalization, and early intervention for children, proper protocols play an important role in documenting infants' progress and effects of early interventional programs. This study aimed to translate Proctor’s Developmental Vocal Assessment Protocol into Persian, make cultural adaptations, assess Persian version of Developmental Vocal Assessment Protocol (P-DVAP)'s validity, internal consistency, and reliability, and provide a general perspective toward Persian infants' vocal behaviors. Methods: This study was mainly conducted in reference to Beaton’s guidelines included translation, synthesis, back-translation, expert committee review, & pretesting. Ten well-experienced speech and language therapists contributed in expert committee review. Mothers of 202 infants were interviewed by experienced speech and language therapists. Results: Expert committee pointed out some difficulties that parents might have responding to P-DVAP. Such difficulties were sorted out in the P-DVAP applied for psychometric analysis. The Content Validity Index and Content Validity Ratio of P-DVAP were above 0.9. In test-retest reliability, Kappa coefficient was 0.6 and as the measure of inter item consistency, Kuder-Richardson-20 for each stage ranged from 0.1 to 0.5. Parents of typical infants reported variations in crying, vegetative sounds, laughing, prosody changes, babbling, approximants of meaningful words, and consonant-vowel structures as the most common vocal behaviors. The number of vocal behaviors reported for preterm infants after corrected gestational age was fewer than those of typical full-term infants. Conclusion: The P-DVAP is a comprehensive, reliable, valid, simple and clear protocol for clinical evaluation of Persian infants’ vocal behaviors. Keywords: Vocalization, Assessment, Infant, Psychometrics, Child Development
3 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
1.1.
Introduction
Vocalizations in infants begin at birth, and early vocalizations are progressively refined into intelligible speech [1, 2]. There is a schedule for stages of vocal development during first year. Just after birth, the first vocal behaviors include crying and vegetative noises. Next 26 weeks, infants have Cooing, and Babbling as their significant vocal milestones. Reduplicated, variegated, and canonical babbling appear later [3]. These vocal milestones are associated with some specific vocal behaviors that appear to play role in connecting sound to meaning. These specific vocal behaviors include echolalia (an immediate imitation of some other speakers), jargon (long strings of unintelligible sounds with adult-like prosodic and intonational patterns), and Phonetically Consistent Form (speech-sound pattern with consistent prosodic form [4, 5]. Vocal behaviors are evidences of the connection between early babbling and later spoken language [5]. Including basic features of adult speech [5] and having relationship with early speech development [6] make infants’ vocal behaviors an interesting subject to be investigated indepth specially for infants who have risk factors such as hearing loss or cleft lip and palate [7, 8]. The most common assessment tool of infants’ vocal behaviors is parents’ proxy reports. The usual questionnaires for this aim include the chronological ages of vocal milestones defined by different studies [9-12]. In these tools, there are usually five stages and despite some differences, each advancing stage in these models is distinguished from previous stages by the addition of more advanced vocal behaviors. In spite of the values of infant vocal assessment, speech and language pathologists (SLPs) in Iran have access to very few valid measures to examine infant vocalizations, while values of such tools in the matter of the connections between early vocalization and later language development [13] and advantages of early identification and intervention [12] are undeniable. Oryadi-Zanjani [14] presented the Persian version of the Production of Infant Scale Evaluation (PRISE). While appropriate steps were taken to provide the cross-cultural adaptation of this instrument, the Persian version of the PRISE contained only 11 items and was presented specifically as an assessment tool to assist in the early diagnosis of hearing loss and evaluate the effectiveness of cochlear implants in infants with hearing loss [14]. This highlights the need for proxy-report instruments for a wider range of purposes in the assessment of early vocal behaviors in Persian infants. In the other hand, most instruments used for early vocal development assessment have been developed in English-speaking countries. If these instruments are simply translated and used clinically in different cultural and linguistic contexts, the validity of the tool may be
4 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
compromised [15, 16] and some concepts may be lost in translation. Adapted assessment tools for early vocal development should be equivalent to the original version in order to provide comparable opportunities to observe vocal behaviors [16, 17]. Therefore, before the original English versions of the vocal development questionnaires are used in non-English countries, the English versions should be adapted to minimize the systematic biases and maintain its content validity across cultures [17]. One of these vocal assessment tools is Developmental Vocal Assessment Protocol (DVAP) developed by Proctor in 1989 which examines early vocalizations from birth to age of 12 months in five stages (0-2, 2-4, 4-6, 6-10 and 10-12 months). Each stage encompasses a set of items to assess the presence of specific vocal behaviors. In addition, to supplement the report provided by caregivers, the vocal behaviors of infants could be directly observed during routine activities or through recording a sample of their vocalizations. Although the DVAP is not a norm-referenced assessment tool, it has guideline [6, 18] that makes it a proper tool to check infants’ changes during intervention or typical development and to investigate the need of vocal stimulation during intervention. The stage of vocal development is determined by identifying the highest stage at which there is the presence of at least one listed vocal behavior. If the marked stage matches the chronological age of the infant, vocal development is considered emerging and typical [19]. The DVAP has not been validated for any other languages however it has been used by researchers to make vocal checklist for their own studies [13]. Although, Proctor’s article has been cited by different English studies [20-22], authors could not find any validation process taken place on DVAP for English speaking countries. Probably Proctor’s work could be considered as a pioneer research in the matter of infant’s prelinguistic vocalization. The use of validated parental reports has been developed recently specially for infants and toddlers [13]. When the standardized evaluation cannot be implemented, parents' proxy reports are reliable enough to present valuable data on infant vocalization. Parental reports must be simple, easy to complete, quick, and systematic, which apply to DVAP. Therefore, it seems that this questionnaire is an optimal tool to be adapted for assessing the vocalizations of Persian infants. It is notable that this instrument does not rely on the infants' vocal behaviors as the main criterion to divide the developmental stages and uses chronological division instead, so that clinicians could complete the questionnaire more easily. The present study aimed to translate the original version of the DVAP into Persian, and to evaluate the validity and reliability of this adapted DVAP. Furthermore, through this study
5 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
we described the stages of early vocal development in Persian infants using the Persian Developmental Vocal Assessment Protocol (P-DVAP). 1.2.
Materials and Methods
The study protocol was approved by the Ethics Committee of [deleted for peer-review] (the name of the institute affiliated with the authors). The methodology used in the present study was based on guidelines for cross-cultural adaptation as proposed by Beaton and colleagues (2000) [17]. 1.2.1.
Step 1. Forward Translation
Based on the procedure outlines by Beaton and colleagues (2000) [17], the DVAP was initially forward-translated into Persian by two independent translators who were native Persian speakers (target language of the adaptation) and fluent in English as their second language. The translators were asked to note the difficulties and ambiguities in translation. Afterwards, the translations and the comments reported by the translators were reviewed by the first author in order to identify any ambiguous and challenging phrases and expressions from the original version. In addition, she identified any discrepancies between the two translated versions, particularly reflecting lexical choice and nuanced expressions in Persian. Following that, she moderated a discussion with the translators and the other team members in order to synthesize the two translated versions to produce a single, consensus-based translation in Persian. 1.2.2.
Step 2: Backward Translation
The consensus-based translation was back-translated into English by two independent translators who were blinded to the original version and did not have any role in the previous section. The purpose of the back-translation was to ensure that the forward translation into Persian accurately reflected the content of the original English version and to identify any conceptual errors in the translation [17]. 1.2.3.
Step 3: Pre-testing and Cognitive Interviewing
Following the back-translation and minor adjustments, according to the WHO’ recommendation [23], there was a pilot session, which an experienced SLP interviewed mothers of 10 infants from the target population and filled out the P-DVAP. The goal was to find out the difficulty, ambiguity, or any unacceptable words/phrases of the questionnaire. The SLP and each mother went through each item and asked mothers about special phrases, the responses that came to their mind with first confrontation and what each item was looking
6 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
for. The SLP kept time recording to estimate the amount of time that SLPs need to fill out PDVAP. A report was prepared and the research team looked at difficulties of the P-DVAP from mothers’ perspectives and reached consensus final translation. 1.2.4.
Step 4: Validity
The correspondence author invited 28 SLPs according to their resumes, research interest and work experience to be part of a panel to run content evaluation. Ten signed consent forms were returned. The panel included SLPs who had experiences in NICU, Early Intervention for different groups of infants (with cleft lip and palate or hearing loss), or speech and language intervention for children who had communicative skills at the level of pre-linguistic or emerging language (see table 1). In one session, hard copy of table 2 and the final Persian translation of DVAP was provided for each SLP and each panelist –independent of the others- was asked to rate each item of P-DVAP on clarity (well-written, and distinct concepts), simplicity (easily understandable in Persian), necessity (essential) and relevance (was each item related to the vocalization in infants). Please insert tables 1 & 2 here To calculate Content Validity Ratio (CVR), the present study used Lawshe’s model. First author pooled all responses and reported the percentage of experts who scored each item as essential (Figure 1) and result was interpreted using table 3. The Content Validity Index (CVI) was calculated too. In CVI, the number of panelists who chose score 3 or 4 for each item in the matter of relevancy was divided by the total number of panelists. Items with CVI of 0.78 or higher were considered as evidence of good content validity [24]. Please insert Table 3 Here Twelve infants were randomly chosen and re-evaluated 10 days after the first evaluation to estimate test-retest reliability. The inter-item consistency was calculated to find out the level of relationship among items. 1.2.5.
Step 5: Pre-testing of the P-DVAP
The next stage of the cross-cultural adaptation was to evaluate the P-DVAP in terms of potential clinical use with the target population [17]. The authors recruited Persian-speaking infants aged 0-12 months and their parents via convenience sampling from the available database of a health centre in Semnan city, Iran. Three hundred thirty two infants aged 0-12 months had been registered in the database. All registered families were invited to participate in the study by their own health advisors. In
7 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
total, 202 parents (59.9%) whose infants were aged 0-12 months agreed to participate and completed the first interview. During the first interview with mothers, different types of data were collected such as demographic information and infants’ developmental histories. The infants and their families came from Semnan city. The range of the number of family members was from three to five. All parents spoke Persian. It was quite challenging to find out reality of socioeconomic status (SES) through family income or parental occupation. However, maternal education as another index of SES [25] was more reliable to be reported. Table 4 shows the education level of the mothers and number of their infants in each age group. The mean ±SD age of the participating mothers was 28 years ± 5.7 years. Please insert table 4 here During the first interview, developmental history data were collected regarding hearing acuity, prematurity, presence of jaundice, head trauma, asphyxia, anoxia, and other birth and developmental defects. Hundred twenty nine full-term infants (63.9%) had no obvious signs of sensory, physical, and mental handicaps, without any history of jaundice, hypoxia and they all passed auditory screening test without any problem. The other 73 infants (36.1%) had some problem in their medical history (See table 5 for more details). Insert table 5 here please Health advisors provided reports of infants’ general development according to standardized version of Ages and Stages Questionnaire for Iranian children [26] and mothers’ mental health based on their routine evaluation at health centers. Health advisors confirmed that infants were in typical range of general development and their mothers did not have any specific mental health problem. The P-DVAP was filled out via face-to-face interviews with all participating mothers by two experienced SLPs, and the interviews were audio recorded to evaluate the accuracy of the collected data. The P-DVAP from the step 4 was completed with the assistance of the parents rather than the direct observation of the infant by the researchers. The examiners followed the English guideline. For instance, if an infant was aged 5 months, the SLP asked the items present in the third stage (4-6 months). Production of only one vocal behavior was necessary to show the infants vocalizations were as expected based on their age. If the infant did not express one of the listed behaviors in the stage 3, the SLP moved one stage back and investigated the items of the second stage. Likewise, if stage 2 vocal behavior was not present in parent report, first stage items would then be asked. 1.2.6.
Step 6: Statistical Analysis
8 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
Data analysis was performed in SPSS version 24. The face and content validity of PDVAP was assessed based on the mean scores achieved by the rating of each item. In the matter of inter-item consistency of each stage, Kuder-Richardson 20 through the STATA-11 and for the test-retest reliability, Kappa as the measure of agreement through SPSS 24 were administered by an epidemiologist. 1.3.
Results
1.3.1.
Steps 1 to 4
The P-DVAP has been developed from the cross-cultural adaptation of the English version of the developmental vocal assessment protocol [12]. In the cross-cultural adaptation, some modifications were inevitable; however the number of the items in the English version remained the same in the Persian version. There are eight vowels in the DVAP (i, I, e, ʌ, u, U, o, a), while there are six vowels in the P-DVAP (i, e, u, o, a, â). It was rather difficult to find transparent, equivalent Persian substitutes for words such as ‘squeal’, ‘growls’, ‘fussing’, ‘grunting’, and ‘blowing raspberries’. To be able to transfer similar contents in the case of these specific words, the translators used native Persian phrases and in backward translation, it did not affect the English version. In pretesting and cognitive interviewing, mothers asked for some examples to be able to give a better response for some items (e.g., item five in stage five “prosodic counters to match intonation patterns”). Such items needed to be thoroughly explained to obtain reliable responses. If mothers still had problem with a specific item, the SLP provided videos to help mothers. Their answers were so close to what they had in their minds in first confrontation. Mothers recognized the concepts of items correctly and they did not need to do any rewording or rephrasing to be able to answer each item. Even some mothers showed some of their own infants’ videos to certify the presence of specific vocal behavior. The examiner needed three to six minutes to fill out P-DVAP for each mother. The need for different timing was the result of differences in the number of items in each stage and sometimes difficulty of some items. The expert panel suggested that some items be presented as complete sentences instead of using infinitives in their Persian structure, so that the items would be more comprehensible for Iranian SLPs and parents. In the matter of surface validity (clarity and simplicity of PDVAP) which is a part of content validity [27], 70-100% of the SLPs (N= 10) graded all the items 3 to 4. Therefore, the items in all of stages were clear regarding the use of Persian words, content, and structures and they were quite simple. CVR was equal to 0.9 and CVI was
9 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
equal to 0.98. As such, the content validity of the Persian adaptation was good according to Polit, Beck and Owen (2007) [24]. Test- retest was taken place on 12 infants; the Kappa as the measure of agreement was 0.6. This might be able to show that P-DVAP has moderate reliability according to Landis and Koch scale [28]. The Kuder-Richardson 20 coefficients as measure of inter-item consistency for stages one to five were 0.34, 0.16, 0.53, 0.54, and 0.08 respectively. 1.3.2.
Steps 5: Typical Infants
All infants showed matching vocal behaviors to their chronological age indicating typical development as it was expected since none of the infants (n=129) had any significant medical or family history for health, speech, and language problems. Table 5 shows the percentage of the mothers reporting each vocal behavior in their infants in P-DVAP. There were no missing responses in the present study because the examiner was responsible to check all items with mothers. Less than 50% of the mothers with full term typical infants reported all four behaviors across the five stages to be demonstrated in their infants. Behaviors included stage 3) increases in the number of consonants, stage 4) nonreduplicated consonant-vowel sequences and the first words, and stage 5) jargons, protowords, and phonetically consistent forms (Table 6). Please Insert Table 6 here It seems that the mothers were more confident about the non-speech sounds in their infants since crying and vegetative sounds were reported by more than 80% of the mothers, while speech vowels (item five in stage 1) were reported by 50% of mothers. In the second stage, the vocal behaviors associated with speech usage of consonant + vowel structures mainly “coo” and “goo” were observed by only 50% of the mothers. For non-speech sounds, however, more than 75% of the mothers reported a significant reduction in the crying of the infants, as well as the increased demonstration of pleasure sounds. The parental reports of vocal behaviors in the third stage did not follow the same patterns of the first and second stage. In this stage, some of vocal behaviors associated with actual speech were reported by approximately 90% of families, although reports some specific consonants (item 4) were still below 50%. Apparently, the items in the fourth stage were relatively challenging for the families since none of the items were reported by 100% of the mothers. However, canonical or reduplicated babbling as a significant vocal behavior was reported by 90% of the mothers. All items in stage 4 were focused on speech and language development. Difficulty in the
10 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
detection of speech sounds (consonants or vowels) by non-expert individuals might be the reason for parents not reporting behaviors associated with speech sounds in their infants. Over 80% of the mothers reported vocal behaviors corresponding to syllables and approximations of meaningful, single words in stage 5. However, changes in prosody, variegated babbling, and use of jargons were not commonly reported in this age range. 1.3.3.
Steps 5: Infants with Problems in their Past Medical History
According to table 7, preterm infants whose ages were corrected for gestational age had fewer numbers of vocal behavior compared with full term typical infants. It should be noticed that these preterm infants were recognized typical on their ASQ reports. Please Insert Table 7 here The other 10 infants with other types of past medical histories showed fewer numbers of vocal behaviors too. However the number of these infants was not enough to reach a confident result. 1.4.
Discussion
The present study described the initial stages of the cross-cultural adaptation of the DVAP for Persian infants. This was the first investigation regarding early vocal development in Persian infants aged 0-12 months. We adapted the original version of the instrument in terms of the cultural and linguistic environment in Persian clinical settings in accordance with the guidelines recommended for the process of cross-cultural adaptation by Beaton and colleagues (2000) [17]. Following these guidelines has practical advantages over a simple forward translation since it minimizes threats to the validity of the instrument due to inherent cultural and linguistic biases, thereby ensuring the cultural, linguistic, and conceptual equivalence between the original and adapted versions [15-17, 29]. Our findings suggested that the P-DVAP has good content validity, and moderate reliability. The cross-cultural adaptation of DVAP also provided an opportunity to investigate early vocal development in Persian infants for the first time. Vegetative sounds, crying, pleasure sounds, intonational encounters, laughter, canonical babbling, and word approximants were easily recognized vocal behaviors by the parents. This finding was in concert with the description of early vocal behaviors in English infants [9-12]. According to the results of the present study, it is not likely that Persian infants produce their first words around the age of 10 months. This finding supports the previous findings for the Persian children that the first words will be produced around 12 to 14 months [30] The similarity between what parents reported in the present study and the previous reports on English infants’ vocal behavior in addition to the moderate reliability in test-retest
11 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
can confirm that parents can reliably recognize milestones of infants’ vocal behaviors. This finding supports previous findings that parents are accurate observers of their infants vocal behavior [31]. They were more confident about some certain vocal behaviors when they were given videos or examples. This finding was in agreement with finding reported by Lyytinen and her colleagues (1996) who found concrete examples of vocal behaviors helped parents to recognize vocal behavior reliably. Preterm infants whose ages were corrected for gestational age showed fewer numbers of vocal behaviors compared with their typical age peers. This study did not look for the cause of such finding, however, Salerni and colleagues in 2007 analyzed mother-infant dyads and found out that in the conversations of mother-preterm babies, mothers were highly responsive and their preterm infants were not active during interaction [32]. Some vocal behaviors in P-DVAP such as that were only reported by 50% of the parents (ex. hearing the first words around 10 months) in the current research could be eliminated after further investigating of the questionnaire. It is recommended that further research be conducted in order to clarify the use of the P-DVAP in infants with cleft lip and palate, or those at risk for later communicative disorders. 1.5.
Limitations of the Study
The present study was only based on reports provided by parents. A comprehensive view of vocal behaviors in Persian infants could be achieved through an extended study covering clinical observations, and home videos, in conjunction with parental reports. A longitudinal study would help answer the question regarding the sufficiency of requiring only one behavior in a stage to document attainment of that stage. 1.6.
Conclusion
In the current research, DVAP was translated in accordance with international guidelines and validated by experienced Persian SLPs. According to the results, the P-DVAP is a valid, reliable, quick, useful measure to evaluate the vocal behaviors of infants based on their chronological age. 1.7.
Acknowledgments
Hereby, we extend our gratitude to Proctor [12] for the permission to adapt the developmental vocal assessment tool to Persian. We would like to thank Dr Jae Hyun Kim (a Lecturer in the Master of Speech and Language Pathology program in the Department of Linguistics, at the Macquarie University, Australia) for his contribution to the editing and writing of this manuscript, and the families who participated in the study. We are extremely grateful to the ---- for the financial support of this study (grant number: ---).
12 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
1.8.
Conflict of Interest: Authors declare that they have no conflict of interest.
13 Cross-cultural Adaptation and Psychometric Assessment of a Persian Version …
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15
Table 1: Summary of Information regarding to Content Validity Panelists Speech and Language Pathologist
University Degree
Years’ experience
Employment setting
1
Master
9
NICU + clinic
2
Phd
6
Clinic + University
3
Phd
15
NICU + University Clinics
4
Master
16
Clinic
5
Master
8
Clinic
6
Master
28
Clinic
7
Bachelor
16
Clinic + Schools
8
Phd
6
Clinic + University
9
Master
6
Clinic
10
Master
16
Clinic + Schools
16
Table 2: The items included in the questionnaire to evaluate content validity of the P-DVAP
Clarity
Score Simplicity
Score Relevancy
It is 4 completely clear with proper writing. It is relatively 3 clear with proper writing.
It is quite 4 simple and Persian*.
It is relatively 2 clear and its writing needs to be corrected. It is not clear 1 and its writing is full of errors.
It is almost 2 simple with some English words It is 1 complex with English words.
It is largely 3 simple and Persian
It is completely related to the development of vocalization in infants. It is largely related to the development of vocalization in infants. It is slightly related to the development of vocalization in infants. It is not related to the development of vocalization in infants.
Score Necessity 4
It is quite 4 essential.
3
It is 3 relatively necessary.
2
It is useful.
1
It is not 1 necessary.
* In the information sheet, we asked the experts that questionnaire MUST be only in Persian not any modified English words.
Score
2
17
Table 3: Lawshe’s Model to Interpret CVR The number of panelists 5 6 7 8 9 10 15 20 25 30 35 40
The Minimum Level of Validity 0.99 0.99 0.99 0.75 0.78 0.62 0.49 0.42 0.37 0.33 0.31 0.29
18
Table 4: Maternal Education
Maternal Education
Total
Illiterate Primary Guidance school Diploma Bachelor Master and PhD
0-2+ 3 10 12 20 12 4 61
Infants Age Groups 2-4+ 4-6+ 6-10+ 5 2 5 1 5 10 5 1 1 5 8 22 4 7 14 3 5 3 23 28 55
10-12 2 2 2 15 12 2 35
Total 17 28 21 70 49 17 202
19
Table 5. Frequency of Infants according to their Past Medical History (PMH) Chronological Age 0-2 2-4 4-6 6-10 10-12 Without any problem 38 17 19 34 21 Jaundice 13 4 7 11 10 Jaundice + Preterm 5 0 1 0 1 PMH Preterm 3 1 1 10 3 Hearing Acuity Problem 1 0 0 0 0 * Complex Past Medical History 1 0 0 0 0 Hypoxia 0 1 0 0 0 Total 61 23 28 55 35 * This child was born preterm, with jaundice and problem to pass hearing screening test.
Total 129 45 7 18 1 1 1 202
20
Table 6: Summary of the Parental Responses on the P-DVAP (n= 129) Vocalization types
Parental reports
Number of Parents = 38
Yes1
No2
No. Stage 1: 0-2 months 1
Crying with sudden pitch shifts, extremely high pitch
81.6
18.4
2
Fussing or discomfort
73.7
26.3
3
Vegetative sounds (burps, sounds accompanying feeding)
97.4
2.6
4
Neutral sounds (grunts, sighs)
36.8
63.2
5
Vowel-like sounds: (/i/, /e/, /u/, /o/, /a/, /â /)
50
50
Yes1
No2
Number of Parents: 17 No. Stage 2: 2-4 months 1
Vowel sounds predominate, but a few consonants emerge (primarily velars and glottals)
58.8
41.2
2
Marked decrease in Crying (after 12 weeks)
82.4
17.6
3
Begins Consonants plus vowel; mostly "coo" and "goo"
52.9
47.1
4
Begins to produce pleasure sounds, such as "mmmmm"
76.5
23.5
1
No2
Number of Parents: 19
Yes
No. Stage 3: 4-6 months Consistent production of consonant-vowel (CV) (syllabic) 1 52.6 combinations
47.4
2
Imitation of sounds in back-and-forth babbling games with 89.5 others
10.5
3
More variations in vowel production
89.5
10.5
4
Number of consonant segments increases to include front 42.1 stops and nasals
57.9
5
Laughter emerges (around 16 weeks)
0.00
6
Front sounds begin to predominate, including blowing 94.7 "raspberries", bilabial trills (lip smacks)
5.3
7
Begins variation of intonational (pitch) contours, often 100 when playing alone with toys
0.00
8
Extreme pitch glides, such as yells, squeals, and low78.9 pitched growls
21.1
Yes1
No2
Number of Parents: 33
100
No. Stage 4: 6-10 months 1
Canonical, repetitive, or reduplicated babbling (CV or CVCV-like structure) begins to appear (/mama/, /dada/, and 90.9 /nʌnʌ /)
9.1
2
Consistent variation of intonational contours
75.8
24.2
3
Early non-reduplicated CV sequences appear
42.9
57.1
21
4
Parent may report hearing first word around 10 months
21.2
78.8
5
Utterances produced with stop consonant (p, b, t, d, are 75.8 most common)
24.2
6
Short exclamations such as "ooh!" begin to appear
75.8
24.2
1
No2
Number of Parents: 21
Yes
No. Stage 5: 10-12 months Variegated babbling (successive syllable not identical) 1 61.9 appears
38.1
2
Variety of CV and CVC combinations with sentence-like 81 intonation
19
3
Syllables other than CVs produced
85.7
14.3
4
Use of jargon, protowords, or phonetically consistent forms 47.6 emerges
52.4
5
Increased development of prosodic contours to match 52.4 intonation patterns of ambient language
47.6
6
Approximations of meaningful single words; phonological 90.5 processes may operate on word approximations
9.5
1 2
Infant shows the vocal behavior. Infant does not show the vocal behavior.
22
Table 7: Vocal Behaviors in Infants with Different Past Medical Histories
Participants
Number of Vocal
Full-Term Typical Infants (n = 129)
Full-Term Typical Infants with History
Preterm Infants (n = 18)
of Jaundice (n = 45)
Mean
SD
Mean
SD
Mean
SD
Stage I
3.4
1.08
3.7
0.95
2.7
1.16
Stage II
2.7
0.99
3.0
0.00
2.0
0.00
Stage III
6.6
1.26
5.7
1.89
5.0
0.00
Stage IV
3.8
1.28
3.7
1.42
2.4
2.01
Stage V
4.2
1.12
4.6
0.97
3.7
0.58
Behaviors
23
Figure 1: Lawshe’s Method to Calculate Content Validity (ne = number of panelists identifying an item essential; N = total number of expert panel)