Theoretical and practical considerations in the restoration of function after stroke.

Recovery of function after stroke appears to include elements of both restoration and compensation. The brain is highly plastic, which allows reorganization after damage. Stroke produces permanent damage to the brain, so recovery must be based on activity in surviving cells that are either adjacent, contralateral, or in a different region. Furthermore, representation of a particular function in the brain is usually not limited to a single brain region. Multiple representation provides the opportunity for brain reorganization; functions are assumed by surviving brain structures. Compensation can be the initial response in the recovery phase and may persist through later phases because of the new habits formed (as the restraint therapy studies of Taub and others would suggest), because the damage to the brain is extensive and hinders restoration, because of secondary pathology, such as tendon shortening and muscle wasting, that does not allow brain reorganization to be translated into functional recovery, or because of inadequate (especially late) rehabilitation.