Audiometric configuration in non-syndromic genetic hearing loss

Twenty-eight families in which there were 136 members affected by non-syndromic genetic hearing loss were examined to define specific features on the audiogram. There were 83 individuals (12 families) with autosomal dominant (AD), 50 (15 families) with autosomal recessive (AR) and three (one family) with X-linked recessive (XR) hearing loss. The main audiogram shapes found in this study were: sloping (50.3%); residual (26.5%); and flat (21.0%). Specific shapes (ascending and U-shaped) only occurred in 3.7% of AD cases. Audiogram shapes were found to be significantly different between AD and AR families, and showed intra-familial and inter-familial variability. There was a significant difference in the degree of hearing loss between AD and AR, with AD being milder than AR. The results suggested that the audiograms of non-syndromic deafness were usually nonspecific and counselling of family members would be better based on family condition rather then group information.