Clinical Electrocochleography in the Diagnosis and Management of Menière's Disorders

Patients with a fluctuating hearing loss, episodic vertigo and tinnitus with no known aetiological cause were investigated as cases of Menière's disorder. Transtympanic electrocochleography was found to be helpful in reaching the diagnosis of an inner ear disorder. In 65% of the patients, a large DC potential was recorded which caused an apparent widening of the summating potential/action potential (SP/AP) waveform. This potential was thought to be an SP which enhanced relative to the AP component, and believed to be related directly to the presence of endolymphatic hydrops. A method is described which 'scores' the clinical history with respect to certainty of the diagnosis of Meieère's disorder. It was found that the more certain cases, with high scores, were statistically more likely to show an abnormal SP/AP waveform. The results of endolymphatic sac surgery were also assessed over 1 year in 28 cases, and it was found that those patients whose ECochG had revealed an abnormal SP/AP waveform prior to surgery benefitted in a statistically significant manner more from the operation.