Early effects of very early cochlear implant activation on tinnitus

Cochlear implantation (CI) has long been the standard of care for patients with severe-to-profound hearing impairment. Yet the benefits of CI extend far beyond speech understanding, with mounting recent literature supporting its role in tinnitus abatement. However, those studies have uniformly analyzed the effects of tinnitus after the traditional 3-4 weeks waiting period between CI surgery and device activation. As many clinics are shifting these waiting intervals to become shorter (in some cases within 24 hours, little is known about tinnitus abatement very early in the postoperative period. The aim of this study was to compare preoperative and postoperative tinnitus handicaps in this unique but growing population of very early-activated patients.

Twenty-seven adults with severe-to-profound hearing impairment with chronic tinnitus (>6 months) were included. Patients with concomitant psychiatric disorders were excluded. All patients were implanted with the same array and were switched on within 24 hours after the surgery. Tinnitus Handicap Inventory (THI) was recorded preoperatively, immediately after activation at 24 hours postoperatively, at 1 week, 2 weeks, and I month after activation. Wilcoxon signed-rank test was used to compare values between preoperative assessment and respective fitting sessions.

Mean THI 24 hours after implantation increased in comparison to that assessed preoperatively (77.6 vs 72.5, p = 0.001). By 1 week after surgery, the THI had decreased to 54.9 ( p < 0.001). This trend continued and was statistically significant at 2 weeks (36.0, p < 0.001) and 1 month (28.5, p < 0.001).

On average, most patients with tinnitus will note a significant improvement in their tinnitus handicap when activated within 24 hours of CI. However, tinnitus does increase between surgery and 24 hours, most likely reflecting not only intracochlear changes, but modulation of the entire auditory pathway. Following this early rise, the tinnitus continues to abate over the following month. Patients with tinnitus may benefit from early activation, although should be counseled that they may experience an exacerbation during the very early postoperative period.