Activity monitoring in chronic illness: time out of bed for tetraplegics during comprehensive rehabilitation.

Unobtrusive longitudinal monitoring of what patients actually do during comprehensive rehabilitation represents a relatively unexplored but potentially very useful approach to functional evaluation. Recent advances in biomedical technology have created the possibility of supplementing and/or substituting a number of human observations with instrument-based measurements. This paper presents the first data obtained as part of a systematic research effort to explore the feasibility and utility of applying unobtrusive instrumentation to monitor selected patient activities over extended periods of time. The target activity studied was time out of bed for 36 spinal cord injury patients undergoing comprehensive rehabilitation. Measurements were made with a Rest Time Monitor (RTM) which provides a continuous, objective record of when a patient is out of bed, how often and for how long. Based on this experience, a 'standard' activity curve has been developed which is used as a reference in assessing the weekly progress of individual patients. Distinctive types of activity patterns are described in relation to how patients do clinically, and functionally during hospitalization and 12 months after discharge. In addition, data are presented which compare in-hospital activity patterns by level of injury, age and presence or absence of complications. This initial study suggests that longitudinal activity monitoring is a useful tool for clinical assessment and management and may help predict those patients who are most likely to develop pre- and postdischarge complications.