Intraoperative electrocochleography of endolymphatic hydrops surgery using clicks and tone bursts.

Seventy-seven ears of patients with Menière's disease (n = 69) and other ears with secondary endolymphatic hydrops (n = 8) underwent valved shunt surgery, and were monitored with intraoperative electrocochleography (ECoG) using clicks stimuli (n = 77), and both clicks and tone bursts (n = 37). Of the 41 ears in which the "baseline" measurement was > 35% summating potential to action potential (SP/AP) amplitude click ratio, 23 ears (56%) showed a significant ratio decrease (improvement). Twenty-six ears out of the 37 that were monitored by both clicks and tone bursts had abnormal absolute SP tone bursts amplitudes at "baseline" and 8 ears (31%) changed to normal at "closing". When tone burst ECoG information is combined with click stimuli, our basic understanding of click ECoG is enhanced and our ability to assess electrophysiologic changes intraoperatively is improved.