Electrocochleography in syphilitic hearing loss.

Syphilitic labyrinthitis presents such symptoms as hearing loss, tinnitus, vertigo and/or dizziness, and is well known as one of the endolymphatic hydropic diseases. In order to elucidate the relationship between syphilitic hydrops and ECochG findings, we performed ECochG in patients with syphilis following our previously reported study of patients with Meniere's disease. Twenty-two patients who have been serologically and clinically diagnosed as having syphilitic labyrinthitis were examined with ECochG between December, 1982 and November, 1991. Of the 27 ears tested with ECochG, 2 showed no response due to severe hearing loss, and increased SP (SP/AP ratio > 0.37) was observed in 14 (56.0%) out of the remaining 25 ears. The SP/AP ratio of patients with syphilitic labyrinthitis was not significantly different from that of the patients with Meniere's disease or delayed endolymphatic hydrops, while it was significantly higher than that of the patients with sudden deafness and other types of sensorineural hearing loss. We conclude that the electrocochleographic features of endolymphatic syphilitic lesions resemble those in Meniere's disease.