Mapping clinically relevant plasticity after stroke

After stroke, patients show a wide range in the degree of recovery. Recover y occurs on the basis of discrete physiologic events. Identifying and measu ring these events will be useful for a better understanding of stroke recov ery mechanisms. The most extensive experience mapping these events has been with positron emission tomography, functional magnetic resonance imaging, and transcranial magnetic stimulation. This article reviews brain mapping s tudies that have examined stroke recovery. Serial assessment of patients du ring recovery raises the need for control studies evaluating the effect of intra-subject variability over time. The clearest insights into the signifi cance of bilateral activation during unilateral movements by the stroke-aff ected hand will come from studies that include bilateral electromyographic measurements. Most brain imaging studies have focused on patients with very good recovery; further study of patients with a wide range of outcomes is needed. The described brain mapping methods have complementary strengths. I nsights into the biological basis: of recovery may best be achieved when re sults are considered together. With the advent of treatments targeting stro ke recovery, measurement of post-stroke restorative events may also have va lue as a surrogate end point in clinical trials. (C) 2000 Elsevier Science Ltd. All rights reserved.