Chronic pain: electromechanical recording device for measuring patients' activity patterns.

Many authors have recommended the development and use of automated recording devices as alternatives to self-report measures of activity patterns in chronic pain patients. An electromechanical device is described that can be used to measure downtime or uptime in chronic pain patients. This monitor has several advantages over mercury tilt-switch devices including freedom from plane dependence, resistance to artifact associated with rapid or vigorous movements, and the flexibility to permit conceptualization of sitting time as either uptime or downtime, depending upon placement of the position switch. The monitor consists of a miniature electronic timer, a switching delay circuit and battery pack, an electromechanical position switch, a belt with carrying cases, and a battery recharger. The device has high reliability (agreement coefficients of 1.0) and concurrent validity (r = 0.99) for both downtime and uptime assessments. Research applications and clinical use of this device are discussed as well as directions for the further development of automated recording devices.