Electrocochleographic response patterns in a group of patients mainly with presbyacusis.

The latency, amplitude and wave-form of the action potential were studied in a group of patients, mainly presbyacusics and a few with noise-induced hearing loss, sensorineural hearing loss of unknown etiology and conductive loss. Electrocochleographic recruitment with short latency of the AP "threshold" and very rapid increase in amplitude with increasing click intensity was seen in 22%. Partial recruitment with long latency at AP "threshold" but steep amplitude-intensity curves was present in 33%. Only 17% of the subjects showed both electrocpchleographic recruitment (or partial recruitment) and recruitment in the acoustic reflex test. Subjects with conductive loss had normal amplitude and latency intensity curves but they were shifted to the right. The action potential wave-form was normal. Broad action potentials with multiple peaks were the most common in sensorineural hearing loss.