Effect of Electrical Stimulation of Lingual Nerve on Xerostomia: A Randomized Controlled Trial

Introduction: Xerostomia is a subjective sensation of dry mouth affecting millions of people worldwide. Current management has limitations, often causing side effects. This study aims to investigate whether electrical stimulation of the lingual nerve could offer effective relief for xerostomia sufferers.

Methods: Eligible participants were randomly assigned (1:1) to either the experimental or sham group, receiving electrical stimulation of the lingual nerve (n = 24) or sham stimulation (n = 23) for 12 wk. The primary outcome is the changes in xerostomia score using a 100-mm visual analog scale throughout the therapy. Participants assessed their dryness and assigned corresponding scores, with lower scores indicating more severe dry mouth. Secondary outcomes included remission rate in dry mouth frequency, changes in stimulated/unstimulated salivary flow rate (SSFR/USFR), and changes in Oral Health Impact Profile-14 (OHIP-14) questionnaire scores, where higher scores indicate greater impact on oral quality of life.

Results: At week 12, the electrical stimulation group showed greater improvement in xerostomia score compared to the sham group, with a mean between-group difference of 13.8 (95% confidence interval [CI], 10.0-17.6). The therapeutic effect of electrical stimulation was also confirmed by secondary outcomes. The remission rate of dry mouth was higher at 12 wk in the electrical stimulation group (61.9% [95% CI, 40.9%-79.3%] vs. 28.6% [95% CI, 13.8%-50.0%]). Participants in the electrical stimulation group also experienced a greater increase in USFR, with a mean difference of 14.5 (6.1-23.0) μL/min. Moreover, they exhibited significant improvement in OHIP-14 score after 12 wk of therapy, with a mean between-group difference of -10.0 (-13.9 to -6.2). No significant difference was observed between the 2 groups for SSFR (P = 0.702).

Conclusions: Electric stimulation offers promise as a noninvasive, nonpharmacological strategy for the management of xerostomia. Further research is needed to understand its long-term effectiveness, optimal parameters, and underlying mechanisms.

Knowledge transfer statement: The study confirmed that electrical stimulation of the lingual nerve is a promising noninvasive and nonpharmacological modality for relief of xerostomia.