The limitation of risk factors as a means of prognostication in auditory neuropathy spectrum disorder of perinatal onset

Abstract

ObjectiveThe management of hearing loss due to auditory neuropathy spectrum disorder (ANSD) in neonates and infants is challenging because speech and language development prognosis cannot be directly inferred from early audiometric hearing thresholds. Consequently, appropriate intervention with hearing aids or cochlear implantation (CI) can be delayed. Our objective was to determine whether any features of patient history could be used to identify CI candidates with ANSD at an earlier age. MethodA database was maintained over 11 years to monitor cases of perinatal onset ANSD. Risk factors associated with the perinatal time period considered pertinent to hearing outcomes were assessed, including prematurity, birth weight, APGAR score, ototoxic drugs, and hyperbilirubinemia. Children with cochlear nerve aplasia and genetic mutations were excluded. Hearing outcome was determined according to mode of auditory rehabilitation beyond 30 months of age: A) no hearing device; B) hearing aid; C) CI. ResultsOf twenty-eight children with ANSD, nine (32%) had behavioural thresholds and language development sufficient to require no assistive device, 9 (32%) were fitted with hearing aids and 10 (36%) had CIs. The average age at CI (3.45 ± 2.07 years) was significantly older than the age at CI of other children in our program with prelingual hearing loss (2.05 ± 1.14 years; p = 0.01 Mann-Witney U Test). None of the putative risk factors for hearing loss reliably predicted the need for subsequent CI. ConclusionThe small sample size in this study is sufficient to confirm that clinical history alone does not reliably predict which young children with perinatal-onset ANSD will require CI. Consequently, timing for CI remains delayed in these children, potentially affecting speech and language outcome. The pathogenesis of perinatal-onset ANSD remains undetermined and novel means of assessment are required for prognostication in affected infants.