Electrocochleographic study of summating potentials in Menière's disease.

(1) The polarity of summating potentials (SP) and the SP/AP ratio in Menière's disease depend on the electrode position in the tympanic cavity, on the interval between sound stimuli and the method of recording, whether it is by transtympanic or extratympanic recording. (2) In a series of 42 patients with unilateral Menière's disease abnormal SPs were not very closely related to the time elapsed since the onset of vertigo, audiometric pattern, or the results of the glycerol test. (3) It was not possible to differentiate Menière's disease from sudden deafness on the basis of large SP/AP ratios alone. Such ratios were found frequently in both diseases. (4) Recovery or progression of hearing impairment was not always related to changes in the SP. (5) Positive SPs were seen more often in Menière's disease than in other types of sensorineural hearing loss.