Correlation of hearing screening with developmental outcomes in infants over a 2-year period

Abstract

Conclusion: Evoked otoacoustic emission (OAE) and auditory brainstem response (ABR) results for hearing screening among infants have good concordance. However, good correlation with the Griffiths Developmental Scales remains to be desired.

Objective: To correlate hearing screening outcomes of a cohort of infants with developmental outcomes at 6 and 12 months.

Subjects and methods: A cohort of pregnant women was identified in several communities in a rural area (Bulacan province) from April 2002 to February 2003 as part of a population-based study determining maternal exposure to pollutants and infant outcomes, with a total follow-up of 2 years. Pregnant mothers were identified and followed up until delivery at a secondary, provincial hospital. Hearing screening was performed with OAEs and ABR. Mental development of infants was assessed at 6 and 12 months using Griffiths Mental Developmental Scales - locomotor, personal-social, hearing and speech, hand and eye coordination, performance tests.

Results: Among the 1086 babies recruited, there were 724 with hearing assessment. Of these 724 babies, 565 had both OAE testing and ABR. Overall in 1130 ears, OAE and ABR testing showed an observed agreement of 99%, agreement due to chance of 96%, and kappa agreement of 79% (p=0.00) in diagnosing bilateral hearing losses. OAEs had a sensitivity of 86.4% (95% CI 64-96.4%) and a specificity of 99.4% (95% CI 98.6-99.7%). At the end of the study, there were 708/724 (97.8%) infants with normal hearing, 7/724 (1.0%) with unilateral hearing loss, 8/724 (1.1%) with bilateral mild hearing loss, and 1/724 (0.1%) with bilateral profound hearing loss, who demonstrated consistent mental delay throughout. Follow-up rates for developmental examinations at 6 and 12 months were 98% and 81.25%, respectively. In these groups, there were 8 (1%) infants at 6 months and 18 (2.4%) at 12 months with developmental delay (Griffiths Mental Developmental Scales).