Electrocochleographic findings in cases of autoimmune disease with sensorineural deafness

To present electrocochleographic findings in patients with autoimmune disease (AD) with sensorineural deafness (ADSD), and to discuss the etiologies of sensorineural hearing loss (SNHL) in cases of ADSD.

Study design is a retrospective review of electrocochleographic results of 26 patients with ADSD. To evaluate the electrocochleographic results, average SP/AP ratios were compared between ADSD and normal subjects. In the ADSD group, audiologic pattern, fluctuations in hearing and results of the glycerol test were also reviewed. Electrocochleography (ECoG) was recorded using the extratympanic method, and the SP to AP ratio (SP/AP ratio) was analyzed.

The mean of average SP/AP ratios in the ADSD groups (0.46) was significantly higher than that in normal subjects (0.27). Further, 17 of 29 affected ears in patients with ADSD showed fluctuating hearing loss. Eighteen ears showed low tone loss (rising and peak audiologic patterns). Only 5 of 26 ears (19.2%) showed positive results on glycerol test. There was no correlation between glycerol test results and hearing fluctuation or between glycerol test results and the SP/AP ratio on chi(2)-test. There was no tendency between audiologic pattern and glycerol test results or between audiologic pattern and the SP/AP ratio.

These results suggest the etiologies of SNHL in cases of ADSD remain unclear. However, some cases showed clinical findings similar to endolymphatic hydrops. We should bear in mind that clinical Meniere's syndrome involves ADSD. Further investigation is needed to resolve the etiology of SNHL of ADSD.