Customized Electric Suppression of Tinnitus in CI Subjects

Abstract

Problem To determine the degree of tinnitus suppression in cochlear implant patients by systematically varying stimulation parameters as a function of rate, level, and electrode. Methods Five cochlear implant subjects with ipsilateral or bilateral tinnitus were included. Implants were stimulated at a basal, middle, and apical electrode, at 100pps and 5000 pps, at perceived level quieter than the tinnitus and at the most comfortable loudness level. Patients reported stimulus and tinnitus perception on a ten-point scale every 30 seconds during and after stimulus delivery. Results All subjects reported near or complete suppression of tinnitus under one or more test conditions. Complete accommodation to the stimulus occurred often, thus during suppression patients perceived very little sound or total silence. Residual inhibition lasted up to twenty minutes. Two of the subjects noted suppression when low rate stimulation was delivered to an apical electrode. One patient responded only to high rate stimulation to an apical electrode. The remaining two patients reported suppression under multiple conditions. One subject had the most dramatic and consistent effects with low rate stimulation to a middle electrode; high rate stimulation caused rebound tinnitus of up to five minutes. Conclusion All patients experienced tinnitus suppression with electrical stimulation. Low rate stimulation overall was more effective in our subject group, and in two cases was the only effective suppressor. Significance Previous studies utilized only high rates of stimulation, and treatment failures occurred. Electrical stimulation is an effective, reproducible, and well-tolerated treatment for tinnitus but stimulus customization is required on an individual basis.