PHYSIOPATHOLOGICAL INVESTIGATIONS IN A FAMILY WITH A HISTORY OF UNILATERAL HEREDITARY DEAFNESS

We examined several members of the same family with unilateral sensori neural hearing loss. The defect showed dominant inheritance. Clinical examination and auditory tests, including high-definition audiogram an d otoacoustic emission recording, were done to characterize the physio pathological processes of hearing loss, and to investigate possible as ymptomatic auditory features in the normal ear of affected subjects an d nonaffected siblings. Hypotheses as to the underlying mechanisms are discussed, eg, variable expression of bilateral isolated hereditary d eafness, incomplete Klein-Waardenburg syndrome with stria vascularis a nomalies and highly variable gene expression, or unilateral cochlear a plasia. The phenomenon may also be related to the delayed progressive unilateral loss in patients with bilateral hereditary deafness, involv ing perhaps unilateral vascular disorders or a genetically induced deg eneration of cochlear cells or auditory neurons.