1. 2016/1/31 Unobtrusive Assessment of Motor Patterns During Sleep Based on Mattress Indentation Measurements Vincent,,, Vincent Verhaert, Bart Haex, Tom De Wilde,Daniel Berckmans,Marie Vandekerckhove,Johan Verbraecken, and Jos Vander Sloten IEEE ON IN,.,. 5, IEEE TRANSACTIONS ON INFORMATION TECHNOLOGY IN BIOMEDICINE, VOL. 15, NO. 5, SEPTEMBER 2011 : Presenter : Kun-Han Jhan :. Advisor : Dr. Chun-Ju Hou : Date : 2013.03.27

2. Outline Introduction Materials and Methods Results Discussion Conclusion 2016/1/31

3. Introduction 2016/1/31 Inadequate sleep is generally considered as one of the most compelling problems in the industrialized world ◦ Performance ◦ Health ◦ Quality of life Sleep disturbance ◦ Associated with cognitive and emotional stress, or physical discomfort

4. Introduction 2016/1/31 Sleep system ◦ Mattress, supporting structure The main function of sleep systems ◦ To support the human body in a way that allow the muscles and intervertebral discs to recover from nearly continuous loading by day.  The shape of the spine  A slightly flattened lumbar lordosis

5. Introduction 2016/1/31 The mechanical characteristics of a sleep system should be optimized concerning ◦ Body contour ◦ Weight distribution Healthy sleep requires the presence of various posture shifts per night ◦ Posture changes ◦ Body movements

6. Introduction 2016/1/31 The relationship between sleep disorders and specific movement and posture ◦ Arousal and sleep fragmentation  Much movement during sleep  Restless legs syndrome during sleep  Periodic limb movements during sleep ◦ Obstructive sleep apnea syndrome(OSAS)  Body posture: supine

7. Introduction 2016/1/31 The assessment of body movements and posture shifts during the night ◦ Polysomnography (PSG) ◦ Actigraphy ◦ Video analysis

8. Literatures Review Recently, interest in instrumenting the bed has grown to study body movements and monitor sleep. The advantage of this approach ◦ No equipment has to be mounted on the subjects themselves 2016/1/31

9. Literatures Review Lu et al. and Tamura et al. ◦ Assessed changes in bed temperature as an index of body movement Results ◦ Leg movements were detected more accurately than torso movements ◦ The inherently long reaction time of temperature sensors  making it impossible to discriminate between short movements 2016/1/31

10. Literatures Review Van der Loos ◦ 54 resistive temperature devices with an array of 54 force sensitive resistors ◦ Breathing rate and temperature overnight Results ◦ Slept in a supine posture during the entire night 2016/1/31

11. Literatures Review Chan and coworkers ◦ Infrared motion sensors ◦ System was capable of monitoring activity in bed and out of bed Results ◦ It could not discriminate between a person in bed and a person near the bed 2016/1/31

12. Purpose 2016/1/31 This paper focuses on mattress indentation measurements for the unobtrusive assessment of both body movement and adopted sleep posture during the night.

13. Materials and Methods 2016/1/31 Data Collection Analysis of Bed Measurements Analysis of Motor Patterns

14. Materials and Methods 2016/1/31 Sleep systems ◦ Measure the perpendicular indentation of the mattress surface in a 2-D grid of 170 points at a sampling rate of 0.5 Hz mm

15. Materials and Methods 2016/1/31 Fifteen normal subjects (age 17 ~34years) ◦ Nine males ◦ Six females ◦ Body mass indices (BMI): between18.4 and 29.4 kg/m 2

16. Materials and Methods 2016/1/31 The experial process ◦ Registered by the sleep systems ◦ Activation graphic recordings  sampling rate of 32 Hz ◦ The subjects were asked in the morning ◦ Polysomnographic and video recordings served as a gold standard

17. Materials and Methods 2016/1/31 Detection of Body Movements ◦ Z i : potentiometer output

18. Materials and Methods 2016/1/31 Classification of Sleep Posture The indentation measurements into four distinct classes Prone Supine Left lateral Right lateral Support vector machines (SVMs)

19. Materials and Methods 2016/1/31 Classification of Sleep Posture Features Shoulder–hip ratio Knee–hip ratio Total indentation Lateral asymmetry index (LAI) Lower leg indentation

20. Materials and Methods 2016/1/31 Validation graphical user interface

21. Materials and Methods 2016/1/31 All recorded nights for motor patterns based on the following parameters ◦ Body movements(BM) ◦ Postural immobility

22. Results - Performance 2016/1/31 Movement Detection ◦ Higher sensitivity for movement detection based on bed measurements

23. Results - Performance 2016/1/31 Posture Recognition ◦ A training set :139 indentation samples  16 prone  36 Supine:low LAI  44 left lateral:negative asymmetry index  43 right lateral:positive asymmetry index

24. Results - Performance 2016/1/31 Posture Recognition ◦ The test set consisted of 30 fully recorded nights ◦ Mattress indentation, video, and PSG recording ◦ 10 different persons(six males and four females)

25. Results- Analysis of Motor Patterns 2016/1/31 Analysis of Motor Patterns ◦ A total of 60 nights  15 persons(9 males and 6 females, aged 26.1 ± 8.8 years) ◦ Recorded and analyzed for body movements and sleep postures

26. Discussion 2016/1/31 Mattress indentation measurements are useful for the assessment of during sleep ◦ It does not place any burden ◦ It captures movements of the entire body ◦ Complete set of motion related parameters is provided

27. Conclusion Conclusion 2016/1/31 The sensors in sleep systems to provide accurate on motor patterns during sleep The knowledge on adopted sleep postures is important Might be used to advise people on how to change their sleep system settings if their sleep habits change