Early hearing detection and intervention in children with prelingual deafness, effects on language development

The purpose of this study was to assess, the cognitive and receptive language abilities in children with prelingual hearing impairment, in relation to the age of enrollment in the intervention program and examine the related variables.

Seventy children with congenital prelingual deafness were divided into 2 groups based on their age at the start of the intervention program: 17 children enrolled between 0-12 months of age, 53 children enrolled after the age of 12 months. The age of intervention is defined as the identification and confirmation of hearing loss, adaptation of hearing aids, and enrollment in the program of special education at the Orthophonological Institute of Rome. Assessments were carried out at 5 years of age. The receptive language abilities were measured using the Peabody picture vocabulary test (PPVT), while the cognitive abilities used the Raven standard progressive matrices test. The material was administered by staff skilled in assessing children with hearing loss. The assessment of language score tests (PPVT and Raven progressive matrix test) of samples of children with hearing loss was compared with normal standardized scores of hearing peers at 5 years of age. Mean group differences were compared using t-tests. The results were considered statistically significant for a P-value less than or equal to 0.05.

A progressive decline in the mean PPVT score with increasing ages of enrollment was present. The mean receptive language score of the children enrolled within the first 12 months was significantly better (P<0.001) compared to those over 13 months. The nonverbal IQ, determined by Raven's standard progressive matrices, showed no statistically significant differences in IQ scores (P = 0.083) between children with early and late age of enrollment. Our data revealed that language abilities are significantly affected by the degree of hearing loss (P<0.001 Children with very severe hearing loss, find it more difficult to achieve adequate language abilities than children with moderate and severe hearing.

According to previous studies on the matter, our data suggest that identification of hearing loss at early age associated with early hearing aid fitting, and enrollment in early intervention within the first 12 months of age, may help to obtain good results in the receptive language skills performance. The early identification of prelingual hearing loss at birth through the neonatal screening must therefore be, , considered the primary step for accessing a quality intervention.