Effects of aural stimulation with capsaicin ointment on swallowing function in elderly patients with non-obstructive dysphagia

Abstract

Objective: In the present study, an attempt was made to examine the effects of aural stimulation with ointment containing capsaicin on swallowing function in order to develop a novel and safe treatment for non-obstructive dysphagia in elderly patients.

Design: A prospective pilot, non-blinded, non-controlled study with case series evaluating a new treatment.

Setting: Secondary hospitals.

Patients and methods: The present study included 26 elderly patients with non-obstructive dysphagia. Ointment containing 0.025% capsaicin (0.5 g) was applied to the external auditory canal with a cotton swab under otoscope only once or once a day for 7 days before swallowing of a bolus of colored water (3 mL), which was recorded by transnasal videoendoscopy and evaluated according to the endoscopic swallowing score.

Results: After a single application of 0.025% capsaicin ointment to the right external auditory canal, the endoscopic swallowing score was significantly decreased, and this effect lasted for 60 minutes. After repeated applications of the ointment to each external auditory canal alternatively once a day for 7 days, the endoscopic swallowing score decreased significantly in patients with more severe non-obstructive dysphagia. Of the eight tube-fed patients of this group, three began direct swallowing exercises using jelly, which subsequently restored their oral food intake.

Conclusion: These findings suggest that stimulation of the external auditory canal with ointment containing capsaicin improves swallowing function in elderly patients with non-obstructive dysphagia. By the same mechanism used by angiotensin-converting enzyme inhibitors to induce cough reflex, which has been shown to prevent aspiration pneumonia, aural stimulation with capsaicin may reduce the incidence of aspiration pneumonia in dysphagia patients via Arnold's ear-cough reflex stimulation.

Keywords: Arnold’s ear-cough reflex; external auditory canal; oral food intake; swallowing reflex.

Figure 1

Effects of a single aural stimulation with 0.025% capsaicin ointment on endoscopic swallowing score in patients with dysphagia in Experiment 1. Notes: *P=0.017 in Wilcoxon signed–rank test. Data shown as mean ± standard deviation (n=10).

Figure 2

Changes in endoscopic swallowing score after a single aural stimulation with 0.025% capsaicin ointment in patients with dysphagia in Experiment 2. Notes: *P=0.003 in Friedman test; P=0.05 with Shirley–Williams post hoc test. Data shown as mean ± standard deviation (n=6).

Figure 3

Changes in endoscopic swallowing score after repeated aural stimulation with 0.025% capsaicin ointment in patients with dysphagia in Experiment 3. Notes: *P=0.028 in Friedman test; P=0.05 with Shirley–Williams post hoc test. Data shown as mean ± standard deviation (n=10). Abbreviation: NS, not significant.