Superficial
siderosis is a disease in which
iron from
hemoglobin is deposited in the central nervous system, resulting in conditions such as progressive
sensorineural hearing loss,
cerebellar ataxia,
dementia, and pyramidal signs. A 30-year-old man with superficial
siderosis received a
cochlear implant in the left ear, which had shown
complete hearing loss. Good auditory responses were obtained at 14 days after implantation. The postoperative average hearing level with the
cochlear implant was 56.7 dB at 3 months and 55.0 dB at 6 months. However, the patient showed gradual
hearing loss, and the dynamic range changed each time the
electrode parameters were adjusted. To assess residual hearing ability, single-photon emission computed tomography was performed together with an assessment of electrical auditory brainstem response, which showed a good response and increased blood flow in both the temporal lobes. Based on this result, we asked the patient to continue using the
cochlear implant to see whether a perception of speech response would be obtained. However, the patient discontinued using the
cochlear implant because he could not hear satisfactorily. Hearing outcomes after
cochlear implant surgery for patients with superficial
siderosis are not necessarily good. Therefore, the possibility of unsatisfactory results should be fully explained before recommending this surgery to patients.