人工内耳手術を施行した脳表ヘモジデリン沈着症例

Superficial siderosis is a progressive disease of the central nervous system associated with chronic subarachnoid hemorrhage, that could result in complications such as progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs, and dementia. Most patients (95%) experience progressive sensorineural hearing loss that begins early in the disease. Despite the retrocochlear component of the hearing loss, the hearing outcomes following cochlear implantation (CI) for the severe sensorineural hearing loss were variable. We report the case of a 58-year-old female patient with superficial siderosis who underwent CI for severe sensorineural hearing loss. At 2 years after the CI, the postoperative average hearing level was 42 dB. In the speech audiometric test, the monosyllabic discrimination ability without lip reading was 0%, but the correct response rate became 60% when lip reading was added. In this case, the effect of CI was not good, but she received subjective benefit from the CI in terms of both communication and awareness of environmental sounds. However, the performance of the CI may decline due to progression of the disease in the future. Therefore, it is important to explain the possibility of limited benefit accruing from the CI and the risk of progressive performance decline to patients prior to the CI.