Abstract
Electroencephalography (EEG) is a traditional method used in sleep research, but remains inappropriate for routine measurements due to the need for physical restraint and complex attachment of electrodes. For routine monitoring, measurement during sleep in an unencumbered and unrestrained state is essential. The present study focused on body movements during sleep. We extracted the characteristics of body movements during sleep by varying the body sites measured. We measured movements of the following parts of the body during sleep hours:head, trunk, limbs, and whole-body. A NapVIEW was used to detect movements of the head and an Actigraph to detect trunk and limb movements. Additionally, an infrared sensor (NaPiOn) suspended from the ceiling was used to detect whole-body movement. For comparing different sensing sites and different methods of measurement, “body movement timing” was defined as a measure of the rate of temporal concordance with body movement. Results of body movement timing showed high concordance between head and whole-body movements. Significant differences (p<0.001, p<0.01) were observed between limb movement and whole-body movement. Occurrence rates of four kinds of body movement in seven states of sleep were also analyzed. Significant differences were observed in the arousal state during sleep and a state of sleep level 6-8. These results suggest that the arousal state during sleep and a state of sleep level 6-8 can be estimated using body movements.
