Sleep / Wakefulness from Actigraphy

1. Sleep / Wakefulness from Actigraphy Pedro Pires1,3, Teresa Paiva2 and João Sanches1,3 1Institute for Systems and Robotics 2Faculdade de Medicina da Universidade de Lisboa 3Instituto Superior Técnico IbPRIA, Póvoa do Varzim, 2009

2. Sleep Disorders Diagnosis Polysomnography • tests performed on patients during the sleep to evaluate sleep disorders: • monitoring of the patient's airflow through the nose and mouth • blood pressure, • heartbeat as measured by an electrocardiograph (ECG) • blood oxygen level • brain wave patterns (EEG) • eye movements (EOG) • movements of respiratory muscles and limbs. • it is accurate but it is complex and difficult in practice. IbPRIA, Póvoa do Varzim, 2009

3. Motivation A lot of typical sleep disorders involve movement and the actigraphy is a complementary diagnostic tool that may be used to detect these disorders, such as: • Narcolepsy – the condition of falling asleep spontaneously and unwillingly • Periodic limb movement disorder (PLMD) – sudden involuntary movement of arm and/or legs during sleep • Circadian rhythm sleep disorder - jet lag and shift work sleep disorder (SWSD) • Obstructive sleep apnea – the patient can’t get enough deep sleep • Sleepwalking • Sleep paralysis – temporary paralysis of the body shortly before or after sleep • Delayed sleep syndrome (DSPS) – inability to awaken and fall asleep at socially acceptable times IbPRIA, Póvoa do Varzim, 2009

4. Actigraphy • Three-axis accelerometer IbPRIA, Póvoa do Varzim, 2009

5. Movement characterization • The purposeness movements during the daytime are intrinsically different from the purposeless nature of the ones during the night. • Different statistical distributions are associated to each one; Maxwell during the day and Poisson [Gimeno et al.,1999] during the night IbPRIA, Póvoa do Varzim, 2009

6. Daytime distribution model • Acceleration Magnitude Maxwell Distribution IbPRIA, Póvoa do Varzim, 2009

7. Poisson (Normal) Maxwell Mixture ciclo.mpg IbPRIA, Póvoa do Varzim, 2009

8. Distribution Mixture Parameter estimation IbPRIA, Póvoa do Varzim, 2009

9. Sleep/Wakefulness (S/W) state • SW estimation form : IbPRIA, Póvoa do Varzim, 2009

10. Sleep/Wakefulness (S/W) state estimation • Binarization with Graph-Cuts IbPRIA, Póvoa do Varzim, 2009

11. Real data IbPRIA, Póvoa do Varzim, 2009

12. Estimated parameters Exercise IbPRIA, Póvoa do Varzim, 2009

13. An insomnia case IbPRIA, Póvoa do Varzim, 2009

14. SW IbPRIA, Póvoa do Varzim, 2009

15. Conclusions • Purposeness and purposeless movement components of the human activity • Different distributions to describe each component: Maxwell for the vigil and Poisson for the sleep state. • Estimation of the parameters of the mixture, and • Estimation of the Sleep/Wakefulness state using graph-Cuts IbPRIA, Póvoa do Varzim, 2009