Elsevier

The Journal of Pediatrics

Volume 124, Issue 2, February 1994, Pages 199-203
The Journal of Pediatrics

Infant vocalizations and the early diagnosis of severe hearing impairment,☆☆,,★★

https://doi.org/10.1016/S0022-3476(94)70303-5Get rights and content

Abstract

To determine whether late onset of canonical babbling could be used as a criterion to determine risk of hearing impairment, we obtained vocalization samples longitudinally from 94 infants with normal hearing and 37 infants with severe to profound hearing impairment. Parents were instructed to report the onset of canonical babbling (the production of well-formed syllables such as "da," "na," "bee," "yaya"). Verification that the infants were producing canonical syllables was collected in laboratory audio recordings. Infants with normal hearing produced canonical vocalizations before 11 months of age (range, 3 to 10 months; mode, 7 months); infants who were deaf failed to produce canonical syllables until 11 months of age or older, often well into the third year of life (range, 11 to 49 months; mode, 24 months). The correlation between age at onset of the canonical stage and age at auditory amplification was 0.68, indicating that early identification and fitting of hearing aids is of significant benefit to infants learning language. The fact that there is no overlap in the distribution of the onset of canonical babbling between infants with normal hearing and infants with hearing impairment means that the failure of otherwise healthy infants to produce canonical syllables before 11 months of age should be considered a serious risk factor for hearing impairment and, when observed, should result in immediate referral for audiologic evaluation. (J PEDIATR 1994;124:199 203)

Section snippets

Normally hearing subjects

Seventy-three infants were followed longitudinally from the age of 2 months. Infants were recruited by mail solicitation to participate in a study of vocal development. Only infants with unremarkable perinatal and postnatal histories were studied. Twenty-one infants were preterm. Selection criteria for the preterm infants included birth weight between 1400 and 2100 gm and absence of either congenital defects or prenatal or postnatal complications. Infants were excluded if they had evidence of

RESULTS

Figure 1 illustrates that each of the 94 preterm or term infants with normal hearing began canonical babbling before 11 months of age. The onset of canonical babbling for infants with normal hearing ranged from 3 to 10 months (mode, 7 months). In contrast, none of the 37 infants with hearing impairment had an age at onset of the canonical stage before 11 months of age. The onset of canonical babbling for infants with hearing impairment ranged from 11 to 49 months (mode, 24 months). Thus there

DISCUSSION

The key results of this study are as follows: (1) infants with severe to profound hearing impairment are significantly delayed in the onset of canonical babbling, a precursor to the development of meaningful speech; (2) there is no overlap in onset distribution of canonical babbling between hearing-impaired and normally hearing infants, and the failure of canonical babbling to start may be taken as a marker of extreme risk of severe to profound hearing impairment; (3) parents are good

ACKNOWLEDGEMENT

We thank T. J. Balkany, MD, and E. Bancalari, MD, for their helpful comments, and Lynn W. Miskiel and Barbara J. Lewis for their help in assessing the infants with hearing impairment.

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From the Mailman Center for Child Development and the University of Miami Ear Institute, Departments of Psychology, Pediatrics, and Otolaryngology, University of Miami, Miami, Florida

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Supported by grants from the National Institutes of Health/National Institute of Child Health and Development (No. 5 R01 DC00484; Dr. Oller) and from the U.S. Department of Education/ National Institute on Disability and Rehabilitation Research (No. H133 G10118; Dr. Eilers).

Reprint requests: Rebecca E. Eilers, PhD, Mailman Center for Child Development, PO Box 016820, Miami, FL 33101.

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