Characteristics of hearing impairment in children aged six months to two years with global developmental delay

Introduction: Children with global developmental delay (GDD) are at greater risk to have hearing impairments. These impairments interfere with developmental progress or rehabilitation effects. Hearing impairments may be correctable and if so, may improve developmental outcomes. We aimed to study the incidence, characteristics and probable risk factors of hearing impairment in children aged six months to two years with GDD. Methods: In this prospective study, an auditory evaluation was carried out by a trained audiologist in children with GDD. Transient evoked otoacoustic emissions (TEOAE) and brainstem auditory evoked response (BERA) were assessed in these children. Hearing loss was classified based on Goodmann's classification. Results: Of 113 children with GDD assessed, hearing impairment was identified in 35 (30.9%) children. Of 35 children, 22 (62.8%) had isolated sensorineural hearing loss (SNHL). Conductive hearing loss was identified in four (11.5%) and combined hearing loss in nine (25.7%). Of 31 children with SNHL, hearing loss was bilateral in 25 (80.6%). In SNHL, hearing loss was profound in one (3.2%), severe in 14 (45%), moderately severe in three (9.6%), and moderate in five (16.2%). Hearing impairment was associated with 31.7% (20/63) children with cerebral palsy. Kernicterus was another predominant risk factor associated with SNHL. Metabolic disorders, otitis media, tuberous sclerosis, and metachromatic leukodystrophy were other conditions associated with hearing impairment. Conclusions: Hearing impairment is accompanied by about a third of children with GDD. The hearing impairment in children with GDD tends to severe SNHL type in about 45% and bilateral in about 80%.