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.

Improved word perception in tinnitus patients following electrical stimulation of the ear: a preliminary report.

The present study showed that there were close relationships between tinnitus relief and improved word perception by means of a grammatically correct but non-sense Japanese word perception test. Fourteen out of 20 patients reported tinnitus relief and improvement in hearing. Nine out of the 14 patients were thought to be significantly improved in word perception. Improved word perception was observed in 7 out of 10 patients whose ears tested were opposite to ears treated while in 2 out of 10 patients whose ears tested were the same as ears treated. Improved word perception was observed in 5 patients at one segment, 2 patients at two segments and 2 patients at three segments. Improved word perception was observed in one patient at the first segment, 5 patients at the second segment, 5 patients at the third segment and 5 patients at the fourth segment. There were no significant differences in hearing level nor age in patients with and without relief of tinnitus.

Improved word perception following electrical stimulation of the ear in hearing-impaired patients without tinnitus.

Improved word perception in hearing-impaired patients following electrical stimulation of ears was shown by means of a grammatically correct but non-sense Japanese 4-segment sentence perception test. Improved word perception was reported in 15 out of 20 patients without tinnitus following electrical stimulation of ears. In 11 out of 15 patients, the number of incorrect words significantly decreased, showing that electrical stimulation of ears improved word perception. Improved word perception was observed in 5 out of 8 patients whose tested ears were contralateral to treated ears while in 8 out of 12 patients whose tested ears were the same as treated ears. The present study suggests that electrical stimulation of ears improves word perception in hearing-impaired patients without tinnitus.

Evaluation of the tripolar electrode stimulation method by numerical analysis and animal experiments for cochlear implants.

We have proposed the Tripolar Electrode Stimulation Method (TESM) which may enable us to narrow the stimulation region and to move continuously the stimulation site for the cochlear implants. We evaluated whether or not TESM works according to a theory based on numerical analysis using the auditory nerve fiber model. In this simulation, the sum of the excited model fibers were compared with the compound actions potentials obtained from animal experiments. As a result, this experiment showed that TESM could narrow a stimulation region by controlling the sum of the currents emitted from the electrodes on both sides, and continuously move a stimulation site by changing the ratio of the currents emitted from the electrodes on both sides.

An experience of the usage of electrical tinnitus suppressor.

An electrical tinnitus suppressor based on the use of an extracochlear stimulator has been developed at Hokkaido University, Sapporo, Japan, and was implanted in 2 male and 2 female patients. Tinnitus improved in all patients because the auditory nerve was able to be stimulated at home whenever patients wanted treatment. Additional benefits reported after electrical stimulation of the cochlea included sound sleep, relaxation in all cases, and improved hearing acuity in Cases 1, 2, and 4. Minimal temporary complications, including habituation and ear drum perforation, were observed.

Surgical Method for Implanted Tinnitus Suppressor.

A surgical method of fully internal tinnitus suppressor is presented. The surgical approach for the placement of the electrode is very simple and causes less injury to the cochlea. This surgical approach is quite similar to the exploratory tympanotomy. The unit is located at the seat which is drilled in the mastoid bone just behind the external ear canal. The stimulating electrode is introduced to the middle ear beneath the skin of the ear canal on the posterior bony wall. The tip of the electrode located on the promontory is secured by the fascia The primary coil is contained in the Behind-the-Ear case.

Improved Selective Attention and Word Perception in Tinnitus Patients Treated with Electrical Stimulation.

Grammatically correct but nonsense twenty 4-segment sentences mixed with multiple talk recorded on CD were delivered to ears tested in 47 tinnitus patients at a comfortable level via a headphone. The signal-to-noise ratios were 0dB, 5dB and 10dBSPL. Patients were requested to repeat what they heard before and after electrical treatment. A sinusoidal wave of 10kHz at the intensity of about 200mA was delivered to ears for 30 minutes by using a plate electrode for ECG at the tragus or a stimulating Pt-Ir electrode on the middle ear. Alternatively, 0.5mA DC was delivered to patients using a iontophoretic instrument. Improved word perception under noises was observed in most patients with tinnitus relief following electrical stimulation of the ear, demonstrating that electrical stimulation improved auditory selective attention. There may be a relationship between tinnitus relief and improved selective attention. It may be electrical stimulation of the ears that produced improved selective attention, inducing tinnitus relief and improved word perception according to our previous reports.