Aural stimulation with capsaicin ointment improved swallowing function in elderly patients with dysphagia: a randomized, placebo-controlled, double-blind, comparative study

Abstract

Objective: The aim of this study was to assess whether aural stimulation with ointment containing capsaicin improves swallowing function in elderly patients with dysphagia.

Study design: A randomized, placebo-controlled, double-blind, comparative study.

Settings: Secondary hospital.

Patients and methods: Twenty elderly dysphagic patients with a history of cerebrovascular disorder or Parkinson's disease were randomly divided into two groups: 10 receiving aural stimulation with 0.025% capsaicin ointment and 10 stimulated with placebo. The ointments were applied to the external auditory canal with a cotton swab. Then, swallowing of a bolus of blue-dyed water was recorded using transnasal videoendoscopy, and the swallowing function was evaluated according to both endoscopic swallowing scoring and Sensory-Motor-Reflex-Clearance (SMRC) scale.

Results: The sum of endoscopic swallowing scores was significantly decreased 30 and 60 min after a single administration in patients treated with capsaicin, but not with placebo. Reflex score, but not Sensory, Motion and Clearance scores, of the SMRC scale was significantly increased 5, 30 and 60 min after single administration in patients treated with capsaicin, but not with placebo. No patient showed signs of adverse effects.

Conclusion: As capsaicin is an agonist of the transient receptor potential vanilloid 1 (TRPV1), these findings suggest that improvement of the swallowing function, especially glottal closure and cough reflexes, in elderly dysphagic patients was due to TRPV1-mediated aural stimulation of vagal Arnold's nerve with capsaicin, but not with a nonspecific mechanical stimulation with a cotton swab.

Keywords: SMRC scale; capsaicin; cough reflex; dysphagia; external auditory canal; videoendoscopy.

Figure 1

Patient flowchart.

Figure 2

Changes in endoscopic swallowing scores after single aural administration in capsaicin and placebo groups. Notes: *P=0.003 in Friedman test; P=0.05 with Shirley–Williams post hoc test. Data shown as mean ± SD. n=10. Abbreviation: NS, not significant.

Figure 3

Mean changes in endoscopic swallowing scores from baseline (pre) to post-5, -30 and -60 min in capsaicin (black) and placebo (gray) groups. Note: *P<0.05 in Mann–Whitney U test. Abbreviations: NS, not significant; ESS, endoscopic swallowing scoring.

Figure 4

Changes in SMRC scale after single aural administration in capsaicin group. Notes: *P=0.003 in Friedman test; P=0.05 with Shirley–Williams post hoc test. Data shown as mean ± SD, n=10. Abbreviations: NS, not significant; SMRC, Sensory–Motor–Reflex–Clearance.

Figure 5

Changes in SMRC scale after single aural administration in placebo group. Note: Data shown as mean ± SD, n=10. Abbreviations: NS, not significant; SMRC, Sensory–Motor–Reflex–Clearance.

Figure 6

Mean changes in reflex scores from baseline (pre) to post-5, -30 and -60 min in capsaicin (black) and placebo (gray) groups. Note: *P<0.05 in Mann–Whitney U test. Abbreviation: NS, not significant.