Therapeutic effectiveness and patient acceptance of a vestibular nerve activation intervention in chronic insomnia

Defined as: “Complaints of disturbed sleep in the presence of adequate opportunity and circumstance for sleep”, insomnia is one of the most common presenting symptoms in the primary care setting [1, 2]. The disturbance may consist of one or more of three features:• difficulty in initiating sleep• difficulty in maintaining sleep• waking up too early [3]. Insomnia can have a serious impact on work performance and maintaining healthy social relationships [4]. Chronic insomnia is differentiated from acute insomnia by individuals experiencing at least one of the symptoms described above for a minimum of 30 days [3]. Predictably, there has been a wealth of research in the areas of assessment and treatment for this sleep disorder, given the impact insomnia has been shown to have on mental and physical health and wellbeing [3-5]. Incidence rates are routinely around 9% of the general population, escalating to 30% for those who report occasional suffering [6]. Many individuals continue to report symptoms of insomnia for many years after initial onset [7]. Areas of particular interest to clinicians, health-care professionals and insomnia sufferers include implementation, acceptance and adherence to therapies that provide effective long-term management. Conventional treatments include prescription medications (sedative-hypnotics), cognitive-behavioral therapy (CBT) and other alternative therapies (e.g. alcohol, herbal remedies and off-label use of other medicines) [3]. While sedative-hypnotics and CBT have been shown to be effective in the treatment of insomnia [3,8], expert opinion counsels against long-term use of sedative-hypnotics due to residual sedation, rebound insomnia, memory impairment, dependency and withdrawal difficulties [9, 10]. In addition, CBT is not easily accessed and patients frequently have difficulty adhering to the strict behavioral program that is typically prescribed [11]. A further area of concern is the limited evidence supporting the efficacy and safety of alternative therapies, despite their widespread use [3]. One promising approach to managing chronic insomnia is non-invasive mechanical vestibular nerve stimulation, which has been demonstrated to affect sleep [12-17]. The vestibular apparatus, in conjunction with visual and proprioceptive inputs, is responsible for maintaining balance under all conditions. Previous studies have used a mechanical rocking motion to induce vestibular activation, mimicking the sensation of infants being comforted by their parents. Improvements in sleep architecture and increased Total Sleep Time, Sleep Efficiency, Rapid Eye Movement and decreased Sleep Onset Latency have been demonstrated when using this technique [12-17]. A unique therapy, designed to non-invasively stimulate the vestibular nerve to promote sleep onset, has recently been developed. As an alternative to the rocking motion delivered by mechanical action, a swaying sensation is artificially created through mild electrical stimulation. Clinical studies have been previously conducted to investigate both the safety and efficacy of this medical device for the treatment of insomnia via a transient insomnia model, with positive outcomes [18, 19]. Individuals with chronic insomnia report similar issues in sleep disturbance to those in transient insomnia, but persistent in nature. Given the limitations of current effective therapies, and the recent emphasis on patient-centered care [20], there is an increasing need for an alternative treatment for insomnia symptoms. It has been shown that patient preference for non-pharmacological treatment was over three times greater than prescription medications [21]. Thus many would prefer a non-pharmaceutical approach if an effective one were available [11]. Vestibular nerve activation may provide such a treatment for chronic insomnia.