[Phanerogenetic retrocochlear low frequency hearing loss].

OBJECTIVE

To study the pathogenisis of retrocochlear low frequency hearing loss.

METHODS

Clinical and audiologic findings [auditory brainstem response (ABR), evoked otoacoustic emission (EOAE), et al] of 29 cases with retrocochlear low frequency hearing loss were studied.

RESULTS

The head injury, acoustic neuroma, peripheral neurophathy, hereditary hear loss, multiple sclerosis and brainstem disease can cause retrocochlear low frequency hearing loss. The typical clinical manifestations of retrocochlear low frequency hearing loss were normal EOAE which cannot be suppressed by contralateral white noise, but with abnormal ABR as well as with no acoustic reflex and -SP/AP > 0.44.

CONCLUSIONS

The results suggest that phanerogenetic retrocochlear low frequency hearing loss should be a syndrome rather than a disease called "auditory neuropathy". The main lesions of the disease are brainstem, cochlear nuclei and auditory nerve.