Optimising outcome assessment to improve quality and efficiency of stroke trials

Substantial progress has been made in treatment of stroke and much of this has been driven by large scale, multi-centre, randomised controlled trials. Although stroke is a frequent cause of mortality, stroke-related disability and functional decline is of equal or greater concern to patients and carers. Thus, to prove efficacy of an intervention for stroke, we need robust methods of describing recovery. Various functional assessment scales are available, the tool recommended as trial end point by many specialist societies and regulatory authorities is the modified Rankin Scale (mRS). We will use the mRS as exemplar to discuss contemporary research around functional assessment for stroke trials, including recent work around structured assessments, assessor training and end point adjudication panels. We will present an overview and critique of these studies and give examples where strategies to improve mRS assessment are impacting on the quality of stroke clinical trials.