Early detection of hearing impairment in a developing country: what options?

The concept of early detection is often predicated on a specified time-interval for optimal neural development in early childhood. This has been facilitated by advances in objective screening methods such as auditory brainstem response (ABR) and otoacoustic emissions (OAE). However, the prospects for this trend in developing countries remain doubtful, because of adverse socio-economic conditions. Consequently, the relative effectiveness of available tests was evaluated to determine the most viable option for mass screening based on findings from a broader study among 359 school entrants (mean age 6.7 years) in Lagos. The specificity of the questionnaire for detecting hearing loss was 94.0 per cent as against 62.4 per cent for otoscopy and 84.0 per cent for tympanometry. The sensitivities for the three methods were 10.0 per cent, 56.0 per cent and 52.0 per cent, while the positive predictive values were 21.7 per cent, 19.4 per cent and 34.6 per cent respectively. Notwithstanding its limitations, the administration of a well-structured questionnaire at school entry, complemented with parental education, may constitute the inevitable and immediate option for an early detection program in a developing country.