This study aimed to detect and measure chest wall motion using an array of unobtrusive pressure sensors placed beneath a mattress. The pressure sensor data was compared to measurements from respiratory inductance plethysmography bands. Five participants performed different breathing patterns in various positions while sensor data was recorded. The pressure sensor signals were aligned using cross-correlation and summed to increase signal amplitude. Inspiration and expiration segments were identified and delays between signals were calculated. When corrected for delays, the pressure sensor data showed similar chest movement detection to the reference plethysmography bands, suggesting this method could enable long-term respiratory monitoring.

1. Measuring Chest Movement Using an Array of Unobtrusive Pressure Sensors

13. Pressure sensor array data before alignment Signal amplitude for deep and regular breathing

14. C. Delays Between Signals RESULTS ∆ T delay values for 400s of regular breathing ∆ T calculation showing delayed pressure signal

16. The overlap between labeled inspiration segments of the three signals were measured both with and without adjusting for the ∆T value. Shifting the delayed signal improves the overlap percentage and brings the pressure to RIP overlap to within 11% of the overlap between the RIP bands. Table suggests that when corrected for ∆T delay, the direction change is synchronized. RESULTS

17. FUTURE WORKS Future work will focus on chest movement analysis and determine particular monitoring needs of older adults in the smart home context.

19. REFERENCES [1] R. Steele, C. Secombe and W. Brookes, "Using Wireless Sensor Networks for Aged Care: The Patient's Perspective," Pervasive Health Conference and Workshops, 2006, pp. 1-10, 2006. [2] D. Foley, S. Ancoli-Israel, P. Britz and J. Walsh, "Sleep disturbances and chronic disease in older adults: results of the 2003 National Sleep Foundation Sleep in America Survey," J. Psychosom. Res., vol. 56, pp. 497-502, May. 2004. [3] P. Varady, S. Bongar and Z. Benyo, "Detection of airway obstructions and sleep apnea by analyzing the phase relation of respiration movement signals," Instrumentation and Measurement, IEEE Transactions on, vol. 52, pp. 2-6, Feb. 2003. [4] K. P. Cohen, W. M. Ladd, D. M. Beams, W. S. Sheers, R. G. Radwin, W. J. Tompkins and J. G. Webster, "Comparison of impedance and inductance ventilation sensors on adults during breathing, motion, and simulated airway obstruction," Biomedical Engineering, IEEE Transactions on, vol. 44, pp. 555-566, July. 1997.

20. THANK YOU