Can Wearable Inertial Measurement Units Be Used to Measure Sleep Biomechanics? Establishing Initial Feasibility and Validity

Abstract

Wearable motion sensors, specifically, Inertial Measurement Units, are useful tools for the assessment of orientation and movement during sleep. The DOTs platform (Xsens, Enschede, The Netherlands) has shown promise for this purpose. This pilot study aimed to assess its feasibility and validity for recording sleep biomechanics. Feasibility was assessed using four metrics: Drift, Battery Life, Reliability of Recording, and Participant Comfort. Each metric was rated as Stop (least successful), Continue But Modify Protocol, Continue But Monitor Closely, or Continue Without Modifications (most successful). A convenience sample of ten adults slept for one night with a DOT unit attached to their sternum, abdomen, and left and right legs. A survey was administered the following day to assess participant comfort wearing the DOTs. A subset of five participants underwent a single evaluation in a Vicon (Oxford Metrics, England, Oxford) motion analysis lab to assess XSENS DOTs’ validity. With the two systems recording simultaneously, participants were prompted through a series of movements intended to mimic typical sleep biomechanics (rolling over in lying), and the outputs of both systems were compared to assess the level of agreement. The DOT platform performed well on all metrics, with Drift, Battery Life, and Recording Reliability being rated as Continue Without Modifications. Participant Comfort was rated as Continue But Monitor Closely. The DOT Platform demonstrated an extremely high level of agreement with the Vicon motion analysis lab (difference of < 0.025°). Using the Xsens DOT platform to assess sleep biomechanics is feasible and valid in adult populations. Future studies should further investigate the feasibility of using this data capture method for extended periods (e.g., multiple days) and in other groups (e.g., paediatric populations).

Quantitative detection of sleep apnea in adults using inertial measurement unit embedded in wristwatch wearable devices

“…The obvious utility of IMUs is in determining body positioning and detecting body movements during sleep. IMUs worn on the trunk, legs 22 , and wrists 23 have been used for assessing sleep quality and detecting specific changes to neurological disorders such as Parkinson's disease 24 and periodic leg movement 25 . IMUs are also used as sensors to detect seismocardiogram 26 , and pulse-synchronized jerks in acceleration detected by a wrist-worn IMU are proposed as an indicator for sleep–wake classification 27 .…”

A Comparison of Inertial Measurement Units and Overnight Videography to Assess Sleep Biomechanics

“…For example, Brown et al assessed only gross body position and coded only in cardinal positions (supine/prone/left side lying/right side lying) [ 23 ]. Further, because the DOTs performed well against both a lab-based standard reference system (VICON motion analysis) [ 24 ] and the current clinical standard of overnight videography, future studies utilising the DOTs alone need not be constrained by human perception, and different versions of the BODS with finer gradations can be used. While this study focused primarily on classification of static positions, the BODS (with data captured by the DOTs) also allows for recording the number of repositionings/night by registering the number of transitions between sections.…”