Sleep Movements

A good night’s rest is essential to quality of life. Insufficient or poor quality sleep may result in drowsiness and loss of concentration, which adversely affects productivity and well-being during the day. After having sleep problems for an extended period of time, existing illness-related problems can worsen or cause extra difficulties for the patient. For patients suffering from Parkinson’s disease, COPD, or from the effects of a CVA these are familiar problems. The Sleep Movements Module of the MoveMonitor classifies movement information during night’s rest.

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Method

Night’s rest is identified by using the duration and frequency of lying periods. The movement intensity is used to identify transitions during night’s rest. Beginning and end of these transitions can be accurately detected, due to the high resolution of the measurements. Of each transition the magnitude and average velocity are calculated, using the change of inclination of the trunk. Average movement intensity during movement time is calculated.

Research

This analysis is based on the activity classification of the MoveMonitor which is validated [1] and the high reproducibility of the DynaPort accelerometer [2]. The validation study of the Sleep Movement module is submitted for publication.

Outcomes

Going Out of Bed

If the subject leaves the bed for a short while between going into bed in the evening and getting up in the morning, this is called an ‘out of bed period’. The total amount of ‘out of bed periods’ and the beginning and the end of each period are displayed.

Night's Rest Detection

The MoveMonitor activity classification is used to identify the night’s rest. This yields information about the time of going into bed in the evening and getting up in the morning. Any period of lying that lasts longer than 3 hours, which is interrupted for less than 15 minutes, will be detected as night’s rest.

Postures

The inclination of the trunk is used to trace the subjects’ postures. The postures ‘left side’, ‘right side’, ‘prone’, and ‘supine’ are detected and are shown in a graph. Besides this, the absolute and relative duration of each posture are displayed.

Movement Time

By calculating the size of the rotation vector of the DynaPort every movement is detected. Movement Time indicates the percentage of time that movement is detected. Movement Time per minute is also shown in a graph.

Movement Intensity

The size of the rotation vector is used to calculate the intensity of all movement periods. The average Movement Intensity per minute is shown in a graph. The average Movement Intensity of all movement periods is displayed.

Transitions

Each rotation of more than 10 degrees is called a transition. Each transition is classified in one of four classes: small shifts, medium shifts, large shifts, and extra large shifts. For every class the frequency, average velocity, and average duration are shown.

1. Langer, D., Gosselink, R., Sena, R., Burtin, C., Decramer, M., & Troosters, T. (2009). Validation of Two Activity Monitors in Patients With COPD. Thorax, 64, 641-642. doi:10.1136/thx.2008.112102.
2. van Hees, V. T., Slootmaker, S. M., de Groot, G., Van Mechelen, W., & van Lummel, R. C. (2009). Reproducibility of a Triaxial Seismic Accelerometer (DynaPort). Medicine & Science in Sports & Exercise, 41(4), 810-817. doi:10.1249/MSS.0b013e31818ff636.

Sleep Movements

Outcomes

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