Motor activity during sleep in health and disease

Abnormal motor activity during sleep is a symptom or even hallmark of many sleep disorders. Nevertheless, normal or abnormal has been defined only partially for some disorders, and not at all for others. Other motor phenomena during sleep have been described, but their prevalence in the normal population and clinical significance are completely unknown. Polysomnographic studies on motor activity during normal sleep are lacking. Our group has specialized on the investigation of motor phenomena during sleep by neurophysiological and video investigation. The present study aims to better describe and analyze sleep-related motor phenomena in healthy controls and patients with sleep disorders, and to assess normative values for different motor phenomena during sleep. In addition, we aim to develop a prototype of a modular software solution for automatic qualitative and quantitative scoring of various motor phenomena. Approximately 200 patients with various sleep disorders and 100 healthy controls will be included. All study participants will undergo an expanded video-polysomnography with sleep microstructure analysis (arousal scoring), neurophysiological movement analysis with multiple EMG-channels in addition to normal polysomnography (analysis of periodic leg movements and recruitment pattern, analysis of alternating leg muscle activation, hypnagogic foot tremor, high frequency leg movements, quantification of EMG activity during REM sleep) as well as whole-night video analysis (type, distribution, duration, and recruitment pattern of motor events). The project is expected to improve diagnostic methods and clinical practice in sleep medicine. The expected reward of the project is extremely high, because it encompasses both frequent and all forms of sleep disorders as well as a healthy control population. A better understanding of how to discriminate between normal and abnormal motor phenomena during sleep, and improved diagnostic methods are extremely needed in sleep medicine. It is well established, that insufficient or disturbed sleep has multiple serious long-term consequences. Moreover, certain sleep disorders such as REM sleep behavior disorder and its potential precursor REM sleep without atonia provide a unique early window into evolving neurodegenerative disease. For future implementation of quantitative motor analysis in a hospital setting, development of a prototype for a software solution for automatic scoring is the mandatory next step, since manual scoring is very time-demanding and therefore not feasible in clinical routine.

The main aim of this project was the accurate investigation of sleep in healthy subjects, allowing through this analysis a better differentiation between healthy and pathological sleep. To reach this aim, we recruited a cohort of 100 healthy sleepers. The participants were interviewed by experts in sleep medicine, to ensure that no sleep problem was present. After this careful examination, an extensive sleep examination using video-polysomnography was performed. This sleep examination allowed the evaluation of several sleep parameters. As a first step, the sleep stage distribution and sleep quality, as well as respiration during sleep, were evaluated. As participants were distributed in different age groups, it was possible to determine normative values of basic sleep parameters for different age decades. The most important part of this study aimed to an accurate quantitative and qualitative description of movements during sleep in healthy subjects. The presence of movements during sleep, which can be visible or identifiable only through a measurement of the muscle activity, was precisely evaluated and quantificated. Movements that can be present during sleep include, among others: I. Leg movements or muscle activity of the lower extremities, which can be classified in several categories depending e.g. on duration, amplitude, appearance in series or not; II. Movements of the arms; III. Movements of the neck; IV. Muscle activity during REM (Rapid Eye Movement) sleep, which can be precisely classified and quantified according to validated scoring methods. The scoring of several motor activities during sleep allowed the determination of normative values in different age groups, so that through these data the distinction between physiological and pathological movements can be easier. Complementary to this evaluation of movements, the video recordings were analyzed and each movement during sleep was classified according to several parameters (for example, duration, involved body part, qualitative features, etc.). This study quantified accurately and classified for the first time movements during sleep in healthy subjects using high-quality videos. Secondary aim of this project was the validation of an automatic software for the analysis of muscle activity during REM-sleep.