A system for monitoring temperature distribution in bed and its application to the assessment of body movement.

For the assessment of body movements during sleep, a system for monitoring the temperature in bed was developed. The system consists of 16 temperature sensors and a data logger with a memory card. Fifteen of the temperature sensors were arranged in line 6 cm apart on a flat cable. The temperatures at these 15 points in the bed, and the room temperature measured by the additional sensor, were stored on the memory card at predetermined intervals. The data were transferred into a microcomputer and analysed. Changes in posture and body movement were recognizable from the changes in the temperature profile, and well visualized using a three-dimensional display of the successive temperature profiles in the bed. The time of body movement was estimated from the derivative of the temperature profile. Comparison between this estimation and the video recording showed good agreement. The linear arrangement of the sensors provides a high-resolution temperature profile during sleep.