Classification of childhood hearing impairment: implications for rehabilitation in developing countries.

Abstract

To ascertain the rehabilitation needs of hearing impaired school entrants in developing countries based on current criteria for evaluating classification of childhood hearing impairment. The profile of hearing impairment was examined in 50 children from eight randomly selected mainstream schools, based on findings from medical history, physical examination, otoscopy, pure-tone audiometry and tympanometry. The hearing thresholds across frequencies 0.25 - 8.0 kHz were analysed. The results were compared with conventional pure-tone averages (0.5 - 4.0 kHz) and WHO's criteria/threshold for disabling hearing impairment. Seventeen (94.4%) of the 18 children with conductive hearing loss based on conventional audiometry had high-frequency hearing loss. Similarly, 10 children (83.3%) of the 12 children with sensorineural hearing loss and 19 children (95%) of the 20 children with mixed hearing loss had high-frequency hearing loss. Forty-six hearing impaired children (92%): comprising those with permanent unilateral hearing loss > 30 dBHL, permanent hearing loss would have been missed by WHO criteria. Conventional school audiometry and WHO criteria for disabling hearing impairment are unlikely to detect the full spectrum of hearing disability in relation to activity limitation and participation restriction. The rehabilitation needs of the affected children cannot therefore be appropriately addressed by these approaches.