Subjective and Objective Taste Change After Cochlear Implantation Systematic Review and Meta-Analysis.

Abstract

There is a paucity of data reporting the rate of chorda tympani nerve injury during cochlear implantation (CI) surgery. To better provide clarity to patients and surgeons regarding the risk of taste change, we performed a systematic review and meta-analysis of prospective studies examining taste change after CI. PubMed, Embase, and Cochrane Library databases were queried. Databases were queried according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included "(chorda tympani OR gustatory OR taste OR chemosensory OR dysgeusia OR nervus intermedius) AND (cochlea OR cochlear implant OR cochlear implantation)." Prospective studies were included and further divided into "objective" and "subjective" assessments of taste dysfunction. A systematic review was performed for all studies. A random-effects model was used to compare studies with similar methods and patient demographics. The initial database query yielded 2,437 articles, which were screened according to inclusion and exclusion criteria. Nine appropriate studies were identified, including 442 total patients-254 with subjective assessment and 271 with objective assessment of gustation. Seventeen of 144 patients (11.8%) reported short-term taste change (incidence = 0.09 [0.02-0.16], 95% confidence interval with pooled data). Twenty-six of 265 patients (9.8%) reported long-term taste change (incidence = 0.07 [0.01-0.13]). Objective results were heterogenous and therefore not amenable to pooled meta-analysis. Taste change from chorda tympani nerve injury is a likely underrecognized complication of CI and may be the most common adverse consequence of CI surgery. Surgeons should counsel prospective patients on this potential complication and that the risk of taste change may persist longer than the immediate postoperative period.