Usher's syndrome type III: ENG findings in four affected and six unaffected siblings.

ENG recordings showed abnormal findings in subjects affected by Usher's syndrome and in unaffected siblings. Unaffected subjects with hearing impairment may be heterozygote carriers with inner ears more sensitive to various injurious stimuli, e.g. noise, than those of healthy subjects. Vestibular tests may facilitate the detection of heterozygote carriers but the number of patients studied by us is too small to allow definitive conclusions to be reached.