Taste‐strip gustometry in cochlear implanted patients

Objective Investigation of the gustatory function in a large cohort of cochlear implanted patients using lateralized taste-strip tests. Patients and methods One hundred and seven unilaterally or bilaterally profoundly hearing impaired or deaf patients who received cochlear implants (n = 113) were included in this study. Data on gustometry, subjective gustatory dysfunction, and the detailed surgical procedure were acquired retrospectively. Gustatory function, assessed using lateralized taste-strip tests, was performed the day before, 3 days after cochlear implantation, and on the day of the initial CI adjustment (39 days ±7.3 SD). Results Averaged taste-strip scores of the cohort declined significantly from preoperatively 12.3 [11.8; 12.7] (mean [95% confidence intervals]) to 10.5 [9.7; 11.2] on the implanted side about 6 weeks after surgery. Patients with intraoperatively exposed and rerouted, or a severed, chorda tympani nerve (CTN) showed significantly reduced unilateral postoperative scores (10.1 [8.8; 11.4] and 9.3 [8.1; 10.5], respectively), when compared to not exposing or to leaving a bony layer over the CTN. Total taste-strip test scores showed a significant decline 6 weeks postoperatively in CI-patients expressing a subjective gustatory dysfunction (from 23.6 [21.4; 25.8] to 17.5 [14.2; 20.8]), as opposed to patients with a documented subjectively normal taste. Conclusion We consider postoperative gustatory dysfunction as a relevant side effect post cochlear implantation, at least within the first month. Taste-strip based gustometry is a suitable diagnostic tool to assess taste function in CI patients and is recommended to be performed routinely. Level of evidence 3, retrospective, nonrandomized follow-up study.