Neuromodulation of sleep through electrical vestibular nerve stimulation: An update

Abstract

Sleep is the state of unconsciousness where some of the bodily activities are increased and some are decreased. Adequate sleep is essential for homeostasis. Lack of adequate sleep is one of the major public health issues and needs major attention. Prolonged insomnia leads to excessive anxiety and suicidal ideation. The existing pharmacological therapies are effective and associated with side effects. Hence, there is a need for alternative therapy with minimum or no side effects. The vestibular system consists of minute sensory receptors which are basically for regulating posture. However, the vestibular system involves multiple functions related to homeostasis from the level of reflexes to the level of cognition. That is the reason why the vestibular system is called the sixth sense. There are multiple methods to stimulate the vestibular system. Linear stimulation by swinging on a swing, caloric stimulation, vestibular exercises, and electrical vestibular nerve stimulation. Whatever the method adopted, the important thing is the amount of stimulation applied. It should be an optimal stimulus to get beneficial effects from vestibular stimulation. Electrical vestibular nerve stimulation is a safe and non-invasive mode of stimulating the vestibular nerve. Animal studies demonstrated that rhythmical linear acceleration in mice promotes sleep. Here we review the mechanisms behind the sleep-promoting actions of vestibular stimulation. Understanding the mechanisms helps to plan the management of sleep disorders effectively.