Objectives: Quantify the effects of cochlear implants (CI) on tinnitus suppression in patients with previous cochlear implantation using a novel audiologic sequence: Tinnitus Interval Limited Tracking (TILT).
Study design: Prospective cohort study.
Methods: Consecutive patients with tinnitus and previous cochlear implantation for profound hearing loss underwent an audiologic testing sequence called TILT. Patients rated tinnitus severity using the validated Tinnitus Handicap Inventory (THI) as well as a visual analog scale at baseline and in a variety of audiologic scenarios. Changes in tinnitus severity between scenarios allow for the isolation of the effects of masking and electrical stimulation on the reduction of tinnitus.
Results: Twenty patients were enrolled, 10 of whom have tinnitus with average THI 30.2 (standard deviation 22.6). Patients had an acute decrease in tinnitus severity when their CIs were turned on, even in the absence of noise in a soundproof booth. This effect reversed once the CIs were turned off. This effect was greater in magnitude than with masking that occurred with the presentation of soft speech. Acute tinnitus severity trended toward improvement with increased level of presented speech. Degree of improvement was not correlated with THI.
Conclusion: Acute tinnitus suppression in patients using CIs is multifactorial. Masking plays a role; however, it cannot sufficiently account for the totality of symptom improvement experienced by CI patients. Quantifiable tinnitus suppression observed when a CI is turned on, even in the absence of audiologic stimulation, suggests that electrical stimulation is involved in the mechanism of symptom improvement in these patients.
Level of evidence: 4 Laryngoscope, 130: 2047-2052, 2020.
Keywords: Cochlear implantation; TILT; electrical stimulation; masking; tinnitus; tinnitus interval limited tracking; tinnitus suppression.
© 2019 The American Laryngological, Rhinological and Otological Society, Inc.