the innervation densities , i.e . the number of afferent endings per inner and outer hair cell , number of synaptic specializations per inner hair cell and the number of efferent endings per outer hair cell , were evaluated by serial section electron microscopy in the normal human inner ear and a case of usher 's syndrome ( retinitis pigmentosa and sensorineural hearing loss ) .
C0271097
usher 's syndrome
C0018784
sensorineural hearing loss