Language outcome in children with congenital hearing impairment: The influence of etiology

Objectives: To investigate the possible association between the etiology of hearing impairment (HI) and language outcome in children with congenital HI after an early medical-technical intervention and three years of AVT. Methods: A retrospective, two-center study was conducted of 53 patients who were divided in four categories of etiology (degeneratio labyrinthi acustici (DLA) congenita hereditaria, DLA congenita non specificata, DLA congenita postinfectiosa and auditory neuropathy). Language outcome was assessed by examining receptive vocabulary (Peabody Picture Vocabulary Test, PPVT-4), receptive language (Reynell test) and productive language (the Danish `Viborgmaterialet'). All tests were conducted 1, 2 and 3 years after the children received their hearing device. Test scores were calculated from the child's chronological age. Analysis of possible associations was performed using Fisher's exact test and McNemar's test was conducted to examine possible differences between each year of testing for every speech-language test. Subsequently, univariate analyses were performed to search for other possible covariates associated with language outcome. Results: No significant associations were found between the etiology of the HI and the language outcome of children with HI after 1 year of AVT (PPVT, p = 0,234; Reynell, p = 0,845; Viborgmaterialet, p = 0,667), neither after 2 years of AVT (PPVT, p = 0,228; Reynell, p = 0,172; Viborgmaterialet, p = 0,659) nor after 3 years of AVT (PPVT, p = 0,102; Reynell, p = 0,512 Viborgmaterialet, p = 0,580). Some significant associations were found between language outcome and the type of hearing device and between language outcome and additional disabilities, however no strong evidence was found. Conclusion: Most children with congenital HI developed a comparable level of speech and language regardless of the etiology of their HI. This study highlights the interest of further research using objective assessments techniques in a larger and more homogeneous population. If the findings from this study will be confirmed in future studies, this will have a clinical and societal impact regarding the diagnostics of HI.