What is the effect of cochlear implantation on tinnitus in adults with bilateral sensorineural hearing loss?
Background: Unilateral cochlear implantation is a common treatment for patients with bilateral sensorineural hearing loss. An often-reported additional benefit of implantation is the subjective reduction of tinnitus. Most studies reporting on the effect of cochlear implantation on tinnitus have been published in the last decade; however, a current systematic review of the literature following evidenced-based medicine principles is not available.
Study design: Study review of 10 prospective or retrospective case series articles with study populations varying from 20 to 174 patients, from database inception up to January 13, 2015.
Setting: PubMed, Cochrane Library, CINAHL, and Embase databases.
Synopsis: There was a significant post-implantation reduction in Tinnitus Handicap Inventory (THI), Tinnitus Questionnaire (TQ), and visual analogue scale (VAS) scores. Total tinnitus suppression in THI score was found in 30% to 37% of patients, while 29% to 72% reported a decrease, 0% to 30% were stable, and 0% to 25% showed an increase. In the study that used TQ, the score showed total suppression in 8% of patients, a decrease in TQ score in 56%, a stable score in 36%, and no increase of tinnitus. Total suppression measured with other questionnaires ranged from 20% to 45%, with a decrease in 25% to 51% of patients, no change in 5% to 25%, and an increase in 0% to 11%. In the only study in which data in different conditions were extractable, total bilateral tinnitus suppression was present in 41% of patients when the cochlear implant (CI) was off and in 56% when the CI was on. Limitations included a lack of high-quality evidence, a large clinical heterogeneity between studies, limited randomization and blinding, and some missing data or exclusion of patients with missing data.
Bottom line: Overall, current literature shows that there is a decrease of mean tinnitus questionnaire score after unilateral cochlear implantation; however, there is also a chance of increasing burden of existing tinnitus, and, due to methodological considerations, no firm conclusions on CI effectiveness on tinnitus can be drawn.
Citation: Ramakers GGJ, van Zon A, Stegeman I, Grolman W. The effect of cochlear implantation on tinnitus in patients with bilateral hearing loss: a systematic review. Laryngoscope. 2015;125:2584-2592.
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