AN ELECTROCOCHLEOGRAPHIC STUDY OF ACUTE LOW-TONE SENSORINEURAL HEARING-LOSS

Twenty-four patients with acute low-tone sensorineural hearing loss (A LHL) were examined using electrocochleography. The negative summating potential (SP) amplitude and the summating potential/action potential (AP) ratio were significantly greater in the ALHL patients than in nor mals. The SP/AP ratio was smaller in the ALHL patients than in patient s with known Meniere's disease and moderate hearing loss, although the SP amplitude was somewhat greater in the former. An abnormal increase in the SP amplitude following click stimuli was found in 54% of the A LHL patients, while the SP/AP ratio was increased abnormally in 63% of these patients. These findings suggest that the pathophysiology of AL HL may be similar to that for endolymphatic hydrops.