Dimensions of time in illness: an objective view.

It is almost impossible to try to represent and analyze clinical data in the absence of a temporal dimension. The temporal aspect is especially important when automated decision support is used for patient care over substantial periods. This paper emphasizes the crucial role that tasks of temporal reasoning and temporal maintenance play in modern medical information and decision support systems; it also discusses the implications of providing automated support to clinicians who must perform such tasks as part of broader clinical tasks (for example, monitoring and therapy). Temporal reasoning tasks mainly involve intelligent analysis of time-oriented clinical data, and temporal maintenance tasks focus on effective storage and retrieval of these data. Both types of tasks, however, are highly relevant for such applications as patient monitoring, proper use of therapeutic guidelines, assessment of the quality of guideline use, and visualization and exploration of time-oriented biomedical data. Scientists in medical informatics should view the integration of these two areas as a major research and development goal. This paper demonstrates one approach to integration by presenting the concept of a temporal mediator, which combines temporal reasoning and temporal maintenance. Use of the temporal mediator in several clinical tasks is also presented and discussed.