Analysis of taste function in patients before and after cochlear implant surgery

Cochlear implantation (CI), the standard therapy for rehabilitation of severe to profound sensorineural hearing loss, exhibits taste dysfunction as a possible postoperative complication. This study aimed to investigate possible postoperative changes in taste and in addition baseline taste function in CI candidates.

We included 61 patients (32 male, 29 female) planned to undergo CI surgery and 23 healthy controls (8 male, 15 female). Gustatory function was measured using a chemosensory quasi-threshold test (taste strips) and electrogustometry (EGM). To exclude possible effects of olfaction on taste, olfactory function was tested by means of the Sniffin Sticks odor identification test. Furthermore, the density of fungiform papillae (fPAP) was analyzed. Measurements were taken pre- and 2-4 weeks postoperative.

Preoperative taste function and fPAP density was reduced in CI patients compared to controls. The fPAP density correlated significantly with the total taste score, EGM scores and age. Postoperative taste function decreased significantly, whereas EGM scores and fPAP density did not significantly change. Also baseline olfactory function in CI candidates was decreased, whereas no significant change of olfactory function was found post-surgery.

CI candidates exhibited taste and olfactory dysfunction already preoperatively. Furthermore, a significant decrease in taste scores after CI surgery was detected.