Prevalence of Hearing Loss in High Risk Infants of Mediocre Socio-economic Background at Around One Year of Age and Their Correlation with Risk Factors.

The present study tried to determine the hearing threshold by brainstem evoked response audiometry (BERA) in the high-risk infants from a mediocre socio-economic background at around 1 year of age and correlate different risk factors with hearing loss. BERA was done on 127 infants of 6-18 months age of which 87 were high risk. All were given monaural acoustic stimulus using Cz-M1/M2 Montage. Based on the appearance of wave V at minimum stimulus intensity, hearing threshold in decibels (dB) of each ear was determined. To study the association of the individual risk factor with hearing loss multiple logistic regression test was applied. Taking BERA threshold for 'Pass' as ≤40 dBnHL, out of 87 high risk infants 10.34 % (n = 9) had bilateral severe to profound hearing loss, 17.24 % (n = 15) had bilateral mild to moderate hearing loss and 12.64 % (n = 11) had impaired hearing in one ear. All of the control group infants had normal hearing threshold of 30 dBnHL. Twenty major risk factors were identified in the whole study group at an average of 2.3 factors per infant. Twelve factors were examined for correlation using Odd's ratio (OR) with >40 dBnHL threshold as the outcome variable. Factors with very high OR were family history of deafness, Ototoxic drugs and Cranio-facial abnormality followed by others. High risk infants have a persistent and definitive risk of hearing loss prompting early intervention.