Differences and similarities in early vocabulary development between children with hearing aids and children with cochlear implant enrolled in 3-year auditory verbal intervention

OBJECTIVE: The overall objective of this study was to evaluate the implementation of a Nordic Auditory Verbal (AV) intervention for children with all degrees and types of hearing impairment (HI) using all kinds of hearing technology. A first specific objective was to identify differences and similarities in early vocabulary development between children with cochlear implant (CI) compared with children with hearing aids (HAs)/Bone anchored hearing aids (Bahs) enrolled in a 3-year AVprogram, and to compare the group of children with HI to a control group of children with normal hearing (NH). A second specific objective was to study universal neonatal hearing screening (UNHS) using the 1-3-6 Early Hearing Detection and Intervention (EHDI) guidelines.

INTRODUCTION: Effect of AV intervention for children with HI using different hearing technology is not thoroughly studied. It is relevant to question, whether children with mild to moderate HI encounter the same intensive need for AV intervention as children with congenital deafness.

METHODS: A longitudinal and comparative study design was used involving two cohorts of children, i.e. 36 children with CI and 19 children with HA/Bahs. The children were the first in Denmark to receive a 3-year AV intervention by formally trained AV-practitioners. Children were tested annually with standardized speech and language tests, i.e. Peabody Picture Vocabulary test, Reynell test and a Danish test for active vocabulary, Viborgmaterialet. Categorical variables were compared using Fischer's exact test and continuous variables were compared using Wilcoxon-Mann-Whitney test, as data was not normally distributed.

RESULTS: Median age of diagnosis was 6 months and median age at intervention was 13 and 12 months respectively. There was no statistically significant difference between the two groups in terms of scores according to age equivalency for the three tests. However, there was a significant difference between children with HI regardless of hearing technology and children with NH.

CONCLUSION: Children with HI progressed over a three-year period, but they did not reach the same level as children with NH. The high completion rate of 98,2% of families over a three-year period indicates the relevance of AV practice in a Nordic country. Children were diagnosed later than 3 months and intervention also started later than recommended. A result that warrants further investigation.