The principles of spinal cord injury clinical trial programs are briefly reviewed as one example of the challenge faced by most human studies of neurologically directed therapeutic interventions, including rehabilitation strategies. Different trial protocols are reviewed, as are inclusion/exclusion criteria for study subjects, the choice of clinical endpoints, and the statistical approaches that might be used in a trial program. Potential factors that might confound the accurate interpretation of trial data are also identified. Regardless of the specific therapeutic target or the rehabilitation strategy to be evaluated, there are many unresolved issues that will have to be answered before specific and effective prescriptions can be delivered.

clinical trials, confounding variables, human study protocols, responder analysis, spinal cord injury
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