The effect of unilateral multichannel cochlear implant on bilaterally perceived tinnitus

Available multichannel cochlear implants (CIs) provide effective tinnitus suppression. More sophisticated speech strategies are more effective than analogue or slow strategies. The mechanisms by which tinnitus is suppressed by CIs are unclear; however, both acoustic masking and reorganization of the right auditory association cortex induced by the CI are possible mechanisms. CI significantly reduced the tinnitus-related Handicap as assessed by the Tinnitus handicap Inventory (THI).The objective of the study was to evaluate the effects of a unilateral CI on bilaterally perceived tinnitus.Forty-one profoundly deaf patients implanted with a multichannel CI reporting bilateral tinnitus were evaluated. All patients were asked to complete a questionnaire that evaluated the presence, location and intensity of tinnitus before and after cochlear implantation.Seven patients (17%) reported the perception of a 'new tinnitus' after surgery. With the CI off tinnitus was abolished in 23 patients (56.1%) in the implanted ear and in 22 patients (53.6%) in the contralateral ear. With the CI on tinnitus was abolished in the ipsilateral ear in 27 patients (65.8%) and in the contralateral ear in 27 patients (65.8%). Statistical analysis showed a significant reduction of the total THI score and of each subscale score (p < 0.001).