DPOAE-patterns in different types of autosomal-dominant nonsyndromal hearing impairment

Twelve families with autosomal-dominant nonsyndromal hearing impairment (ADNSHI) were examined. The mode of inheritance was determined by pedigree and at least three generations with affected persons had to be found. Pure tone audiogram (PTA), DP-gram and caloric vestibular test (CVT) were performed on 30 affected persons. By PTA we could find eight families with mild to moderate mid-frequency U-shaped ADNSHI, three families with moderate to severe gently sloping high tone ADNSHI and one family with variable ADNSHI. The corresponding DP-grams showed a family-specific DP-gram in 20 (66%) of the examined persons. Seven (23%) showed no distortion-product otoacoustic emissions (DPOAE). In three (10%) persons the DP-grams varied but were also abnormal. The CVT was normal in all cases. Obviously it is possible to find out typical DP-grams in families with ADNSHI. This could be used for early diagnosis of hearing disorders in newborns of such families. Problems could only occur in progredient cases.