Effect of Vestibular Stimulation on Sleep in Elderly

Study Overview
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Brief Summary
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Vestibular stimulation might be beneficial for sleep. Previous research demonstrated that lateral rocking movements can facilitate the transition from wake to sleep during an afternoon nap. However, the relationship between rocking movements and sleep is poorly understood to date. Furthermore, studies looking at the effects of rocking on sleep have not yet been performed in an elderly population. Due to age related changes in sleep, people often experience a decrease in sleep efficiency and sleep quality later in life. Therefore, it is particularly this population that could benefit from a possible enhancement in sleep efficiency and sleep quality. In order to assess the effect of vestibular stimulation on sleep and sleep-dependant memory, measurements of two nights with stimulation will be compared to two baseline nights. The primary outcomes are changes in sleep onset, sleep architecture and power density spectra of the EEG due to vestibular stimulation. Secondary endpoints are sleep dependent changes in memory, the proximal-distal temperature gradient, cardiorespiratory variables and dream content.

Official Title
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Effect of Vestibular Stimulation on Sleep in Elderly

Conditions
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Sleep

Intervention / Treatment
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* Device: Somnomat V4


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Right handed Between 60 and 75 years of age Exclusion Criteria: Diseases or lesions of the nervous system (acute or residual included neurological and psychiatric diseases) BMI < 19 or > 30 kg/m2 Medication known to influence sleep [56] Cognitive Impairment (MoCA score < 26) Drug use and abuse Nicotine use (e.g. smoking) > 10 alcoholic drinks per week > 5 drinks or foods containing caffeine per day History of sleep disorder (Insomnia, sleep apnea (apnea-hypopnea index >5), nocturnal myoclonus (>5 periodic leg movements per hour of sleep)) Irregular sleep-wake rhythm (e.g. shift working) Travelling across time zones less than 1 month ago Naps longer than 1h Sleep on an average night <6 hours or >8 hours Skin allergies or very sensitive skin Diseases of the vestibular system Signs of motion sickness based on questionnaire

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The study has a two-by-two cross-over design. Participants spend two consecutive baseline nights (without stimulation) and two consecutive movement nights (with stimulation) in the laboratory. The order of baseline and movement nights is randomized.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Baseline Nights<br>No vestibular stimulation is applied. However, the sound of the moving bed will be played back to the participant at the right sound intensity level. | |
| Experimental: Movement Nights<br>Vestibular stimulation, in the form of gentle rocking movements, is provided using the Somnomat V4 rocking bed. Stimulation is provided for the entire 7 hours of the night from lights off to lights on. The stimulation frequency is in the range of 0.1-0.3 Hz, with an amplitude in the range of 0.05 to 0.1m | Device: Somnomat V4<br>* Vestibular stimulation is provided using an innervated bed platform. This robotic device consists of a standard single bed, mounted on a moving mechanism. It was developed and produced by the ETH Zürich and approved for use in this study by Swissmedic.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Polysomnography | Difference in sleep parameters between the second of two nights with intervention and the second of two nights without intervention, as recorded using polysomnography. The sleep stages will be scored visually on a 20-s epoch basis according to standard criteria [53]. This will allow us to compare sleep architecture of the participants in the two conditions, as well as a possible consecutive nights effect in the two movement nights. Parameters of specific interest are sleep onset latency, total sleep time, time spent in N1, N2 and N3 stages of NREM sleep and time spent in REM sleep. Furthermore, the EEG power density spectra will be analysed. Power in specific frequency bands will be calculated based on spectral analysis, the amount and density of sleep spindles and slow waves will be determined. | 4 nights of 7 hours each | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Memory performance | Difference in declarative memory performance between the second of two nights with intervention and the second of two nights without intervention. During each experimental night a word-pair recall task will be performed 1h before going to bed and half an hour after waking up. To assess declarative memory performance improvement, we will determine the difference between immediate and delayed recall. Word-pair recall tasks are suitable to determine declarative memory performance in the context of sleep, as they are sensitive to effects of sleep. | Recall moment in evening and morning (4 nights) | 
| Skin temperature | The distal-proximal temperature gradient will be calculated, based on skin temperature measured using sensors placed on the chest and hands, to look for a relationship with sleep onset latency. | 4 nights of 7 hours each |