Taste performance in Parkinson's disease.

While olfactory deficit is already known to be associated with early-stage Parkinson’s disease (PD), taste perception has not fully clarified so far. In this study, we investigated the taste performance in 61 patients with PD and 66 healthy controls (HC) using the Whole Mouth (WMT) and Taste Strip Tests (TST). In addition, we evaluated their olfactory function by means of the Sniffin’ Sticks Test (SST). TST score was significantly lower in PD patients than in HC (TST score 11.0 ± 2.8 vs. 12.2 ± 2.1; p < 0.018) while WMT showed no difference. The olfactory evaluation confirmed the results reported in the literature with a significant reduction of the SST score in PD patients than in HC (SST score 7.0 ± 2.8 vs. 11.3 ± 2.8; p < 0.0001). The conflicting results revealed by TST and WMT could rely on a taste impairment not detectable at supra-threshold concentration of tastes, typical of the daily life. Possible biological correlates of taste impairment in PD are discussed.