Neural hearing loss in a child with poliomyelitis: a histopathological study

The temporal bones of a 26-month-old white female with a paralytic syndrome clinically and pathologically identical to poliomyelitis were examined. The aetiological agent was unknown although a non-poliomyelitis enterovirus infection seemed likely. There was a complete absence of the cochlear neurons and substantially reduced peripheral and central axons with loss of some inner hair cells but preservation of outer hair cells. Scarpa's ganglion, and the geniculate ganglion were partially atrophied. The saccule and utricle were mildly dilated and Reissner's membrane of the apical turn was bulging. In two previous audiological studies a 10--20 dB bilateral sensorineural hearing loss was found in poliomyelitis patients and a neuronal lesion was postulated which is now supported by our findings. This is a rare example of an almost pure neural hearing loss.