Longitudinal unobtrusive measurements in rehabilitation

Most evaluation techniques in rehabilitation emphasize descriptions of patient capability during brief time intervals under relatively standardized conditions. This paper outlines a conceptual approach which emphasizes the importance of evaluating how patients actually perform under everyday circumstances during extended periods of time. The underlying strategy embodied in this approach consists of the following elements: (1) continuous monitoring of discrete activities over extended periods of time (hours to months); (2) data collection wherever the patient goes allowing nontest behavior patterns to be studied; and (3) unobtrusive, noninvasive, and ethically acceptable monitoring to minimize observer bias. Although numerous techniques can be used to obtain these kinds of measurements, recent advances in biomedical engineering make a technological approach both inexpensive and feasible for selected activities. In addition, unobtrusive instrumentation can help generate objective, quantitative information concerning actual patient behavior which provides a previously unavailable data base for evaluating individual patient progress, assessing program effectiveness and developing more relevant outcome measures. Two examples of studies which utilize longitudinal unobtrusive measurements are described and preliminary results are presented.