Neuro-otological function in X-linked hearing loss : a multipedigree assessment and correlation with other clinical parameters

Auditory and vestibular investigations were carried out in 19 affected men and 13 obligate female carriers of 7 pedigrees with nonsyndromic hearing loss segregating as an X-linked trait. In addition, high resolution computerised tomographic scanning was carried out in 24 affected males and 12 obligate female carriers. The neuro-otological results confirm that non syndromic X-linked hearing loss is a clinically heterogeneous condition, but radiological assessment of the cochlea revealed two distinct groups: a normal group, and an abnormal group characterised by a bulbous internal auditory meatus, a dilated facial nerve canal and incomplete separation of the basal coil of the cochlea from the internal auditory meatus. Within a given pedigree there was marked consistency of the presence or absence of the CT scan abnormality in the affected males. One third of the obligate female carriers of the radiologically abnormal pedigrees were shown to have a similar abnormal finding, but as two thirds were normal, rad...