Objective: To propose treatment strength as central to an understanding of rehabilitation treatment, to delineate its features, to examine related research, and to suggest ways to improve the specification and conceptualization of treatment.
Data sources: Published literature.
Study selection: Definitions were proposed for treatment strength components: purity, specificity, dose, intensity, duration, timing, and treater characteristics and organization. Three measures of treatment exposure were selected as having the most research: length of inpatient stay, treatment intensity, and treatment specificity (using as example the stroke rehabilitation unit). Length of stay information was selected primarily from studies using multifacility data systems. All studies identified as using greater treatment intensity or augmented treatment were selected. Because of the large literature on stroke units, selected studies were chosen that used randomized controlled trials or community-based data.
Results: Greater treatment exposure, as measured by length of stay, generally results in greater benefit, although there are wide variations for a given condition over time and across countries. Research on treatment intensity uses various definitions for intensity with mixed results. Specialization, in the form of the stroke rehabilitation unit, generally produces superior outcomes than other types of care, although there is little investigation of the reasons for benefit.
Conclusions: Understanding of rehabilitation treatment would be improved by (1) routinely reporting hours of service by discipline, (2) using treatment strength concepts, (3) analyzing the relation of naturally occurring variations of treatment strength to outcomes, and (4) developing a taxonomy of treatment types.