Oral Somatosensory Sensitivity in the Clinical Assessment of Gustatory Dysfunction

ABSTRACT Objective Food perception has multimodal contributions by taste, smell, and somatosenses. The objective of this study was to investigate oral somatosensory function in patients with gustatory dysfunction. Methods This case–control study was conducted from May 1, 2022 to June 30, 2023 at a tertiary smell and taste clinic. Patients with gustatory complaints and controls were recruited. All participants underwent tests for gustatory function (taste spray, taste strips), oral mechanosensation (letter recognition) and oral irritation (chili powder: 1, 2, 5 and 7 mg). Primary outcome measures were Taste Strips scores, size of oral letter recognition, and self‐rated oral irritation intensity. Results There were 43 patients with gustatory dysfunction and 26 controls. Patients with gustatory dysfunction had significantly lower Taste Strips scores compared to controls (8.0 [7.0–12.0] vs. 13.0 [12.0–15.0], p < 0.001). Patients with gustatory dysfunction rated significantly lower oral intensities of chili at 2 mg (11.4 [4.8–25.2]% vs. 28.6 [23.8–44.8]%, p = 0.002), 5 mg (26.2 [10.0–42.9]% vs. 48.6 [39.0–69.5]%, p = 0.005) and 7 mg (39.5 [24.8–68.1]% vs. 68.6 [50.5–90.5]%, p = 0.008) compared to controls. There was no significant difference in the size of oral letter recognition between patients and controls. Among patients with gustatory complaints, 21 (52.5%) scored ≥ 9 on Taste Strips (considered a normal score); These patients perceived lower oral intensities with 2 mg of chili compared to controls (14.3 [4.8–39.5]% vs. 28.6 [23.8–44.8]%, p = 0.066). Conclusion Altered gustatory perception may be related to changes in chemesthetic sensitivity. Clinical assessment using lower concentrations of chili could be considered in patients with subtle gustatory dysfunction. Level of Evidence 2.