ABSTRACT
The significantly increased incidence of cochlear damage has led many to suggest that tinnitus arises in this organ (4, 5). When cochlear implants became available, it was noted that patients frequently reported improvement in their tinnitus as well as hearing (6). One possible explanation was acoustical masking of the tinnitus by the ambient sounds that the cochlear implant now provided (7). It was also suggested that
tinnitus might have been suppressed by the electrical impulses sent through the auditory nerve by the implant and that external stimulation of the implant might provide additional benefits. Several studies using sundry electrical stimulation techniques reported improvement (8-15) ranging from 22% (11) to 87% (15) depending on the degree of severity, presumed etiology, type and duration of therapy, criteria used to rate benefits, and other factors. Most reported success rates between 50-70% (9, 11, 12) and in one trial, patients with noise induced hearing loss did not do as well as others without this history, and those in the post skull trauma group did the worst. The best results were seen in patients with tinnitus accompanied by disturbances in the vertebro-basilar artery who reported a 64% improvement, including 28% who had complete relief (1). In one small trial in which patients had the ability to induce electrical stimulation when desired on an outpatient basis, tinnitus lessened in all and half reported an improvement in hearing and sleeping (16).
