Educational Objective: The participants should be able to understand the potential role of individualized electrical stimulation of the auditory system in the suppression of tinnitus in patients with cochlear implants.
Objectives: Tinnitus is a debilitating condition in which one perceives sound in the absence of external stimuli. Most treatments consist of masking the tinnitus with an external sound that is louder than the tinnitus. We hypothesize that there exists a characteristic tinnitus signature map in each individual that, when found, can be utilized to suppress their tinnitus at a level that is significantly softer than the tinnitus itself.
Study Design: Prospective randomized single blinded study in a unique individual with a unilateral cochlear implant in an ear with persistent tinnitus and normal hearing in the non-implanted ear.
Methods:
Monopolar electrical stimulation at rates from 40 Hz to 10 kHz, stimulation levels from threshold to the tinnitus mixing point, and stimulation placement from apex to base were administered over a time period of 3 to 10 minutes. Successful suppression was defined as the complete elimination of the subject's tinnitus.
Results: Seven of eighty-three (8.4%) conditions tested led to complete suppression of the subject's tinnitus while delivering a stimulus that was perceived to be softer than the initial level of the tinnitus. Two main characteristics of the signal were found to be effective. Mapping of the parametric space demonstrated that success in suppressing the subject's tinnitus was achieved with very low rates of stimulation at the most apical electrodes and in stimulation with high rates at basal electrodes that closely matched the subject's tinnitus.
Conclusions: Tinnitus suppression is a mechanism specific to the individual. Exploring the parametric space of tinnitus suppression with respect to stimulation rate, sound level, and placement gives insight into the potential treatment of an individual's tinnitus. The development of a clinical algorithm to create individualized maps of tinnitus suppression may lead to the successful treatment of tinnitus.