Laryngopharyngeal Reflux Has Negative Effects on Taste and Smell Functions

Abstract

Objective: We evaluated the halimetric, olfactory, and taste functions of patients with laryngopharyngeal reflux (LPR).

Study design: Prospective clinical study.

Setting: Multicenter tertiary care hospital.

Methods: Patients who were diagnosed with LPR for the first time on the basis of a Reflux Finding Score (RFS) >11 and a Reflux Symptom Index (RSI) >13 were enrolled in this study. A control group was selected from patients without a complaint of LPR. OralChroma was used for the halimetric measurement; Sniffin' Sticks were used for the smelling test; Taste Strips were used for the taste test; and monosodium L-glutamate was used for the umami test.

Results: A total of 110 subjects were included, with a mean age of 36.8 ± 10 years (range, 19-57 years). The differences in odor threshold scores were significant between the groups (P < .001), but no change was detected for the odor identification or discrimination scores between the groups. Bitter taste scores were significantly diminished in the reflux group compared with those in the control group (P = .001), whereas no impairments were found in the other taste scores (sweet, salty, and sour). The reflux group had significantly higher umami taste scores than those of the control group for the posterior tongue and soft palate anatomic sites (P < .001 and P < .001, respectively). Dimethyl sulfite levels were significantly higher in the reflux group than in the control (P = .001).

Conclusion: Questioning patients who present with halitosis, taste, or smelling disorders is important to diagnose LPR.

Keywords: halitosis; laryngopharyngeal reflux; olfaction; taste; umami.