The flavor test is a sensitive tool in identifying the flavor sensorineural dysfunction in Parkinson's disease

Gustatory perception has been poorly explored in Parkinson's disease (PD). Aim of this study was to assess the flavor ability in PD patients, using the "flavor test" (FT), a new standardized and validated tool to examine the flavor perception. Thirty-eight patients (17 F and 21 M) and 36 control subjects (15 F and 21 M) comparable for age and gender were enrolled. All the subjects underwent the flavor test (FT), the Sniffin' Sticks test (SST), and the gustometry test (GT), based on the basic four tastants ("salty," "sour," "sweet," and "bitter"). PD patients presented a FT score significantly lower than controls (p < 0.001). Olfaction (SST) was impaired in PD in comparison with controls (p < 0.001), and the patients also showed a mild reduction of basic tastant identification at the GT (p = 0.08), with a trend toward statistical significance. There was no correlation between SST, FT, and GT. GT performance was negatively correlated with disease severity (p = 0.004) and stage (p = 0.024). The SST and FT resulted abnormal in PD in comparison with controls, independently of disease duration and severity. The ability to identify the basic four tastants was correlated with the disease severity and stage in PD patients suggesting that it might occur later in the course of the disease. FT might be a sensitive tool in identifying the sensorineural perception dysfunction in PD, even in the early stage and regardless of the disease severity.