Evaluation of Implanted Tinnitus Suppressor Based on Tinnitus Stress Test.

An electrical tinnitus suppressor developed at the Hokkaido University was implanted in two women and five men, aged 44-77 years old. To evaluate the efficacy of the suppressor, a self-administered tinnitus stress test (TST), annoyance index (AI), and tinnitus intensity index (TII) were conducted 1 1/2-3 years after implantation of the device. Residual inhibition results found at outpatient clinics and at the homes of patients with implanted suppressors were closely correlated except in one patient in whom the device's electrode was free from the promontorium tympani. The AI registered at a severe level in five patients and a moderate level in two patients before implantation of the suppressor. However, the AI improved after the operation, being moderate in three patients and mild in two, and achieving no level in two patients. After the operation, the TST improved except in one patient whose device had electrode trouble. The TII registered as extreme in all patients before implantation of the suppressor, although the intensity of tinnitus varied from patient to patient according to the loudness balance test. After device implantation, the TII did not register any level in two patients, was mild in another two patients, was moderate in yet two more patients, and was severe in a patient whose device had electrode trouble. After the operation, at TST, AI, and TII results were positively correlated (p =.01), though there was no correlation among these parameters before the operation.