Previous studies have shown that the vestibular system influences sleep, and also that non-invasive electrical vestibular stimulation (VeNS) during sleep significantly improves insomnia severity index (ISI) score.¹ Whilst the individual mechanisms leading to these changes were previously not fully understood, it was generally accepted that sleep was promoted secondary to the non-specific sensation of a rocking motion. Thus, the approach of delivering VeNS during sleep was an effort to replicate this.

Recent experiments, however, have identified prominent vestibular pathways that project into multiple sleep-regulating nuclei of the brainstem and hypothalamus, and have also generated compelling evidence to suggest that the vestibular system directly influences circadian regulation.

Therefore, we hypothesise that repeated electrical vestibular stimulation, when delivered prior to sleep onset, will improve ISI scores.

In this study, 20 adult participants who were identified as having mild to moderate insomnia, where given daily sessions of 30 minutes electrical vestibular stimulation for a period of 14 days. These sessions were delivered approximately 1-hour prior to sleep onset. Baseline ISI was established prior to the study, with repeat ISI scores measured on day 14.

Mean baseline ISI was calculated as 15.7 (moderate insomnia). Repeat ISI score, after 14 days of VeNS sessions, was calculated at 8.15 (sub-clinical insomnia). This result was statistically significant (p-value is <0.00001).

This pilot study supports our hypothesis and suggests that VeNS may hold potential as a non-pharmaceutical therapy in the management of mild to moderate insomnia.

We propose that the mechanism of action is more complex than that of a non-specific rocking motion and may be secondary to the direct influence that the vestibular system has on the circadian pacemaker and other sleep-regulating nuclei in the brainstem.

Reference

1. Zhang, Hongwei. ‘Therapeutic effectiveness and patient acceptance of a vestibular nerve activation intervention in chronic insomnia’ ( 2010).