CORTICAL MECHANISMS OF RECOVERY OF FUNCTION AFTER STROKE

Patients who have suffered hemiplegia from stroke may have some sponta neous recovery that is likely due to reorganization within the cerebra l cortex, Understanding this physiology should be useful in devising w ays to help patients have better improvement. Techniques, such as tran scranial magnetic stimulation and neuroimaging with positron emission tomography, can be used to demonstrate the organization of the human m otor system and do reveal plastic reorganization in a number of situat ions. In relation to stroke, the best recoveries are seen when there i s preservation of the corticospinal tract from the hemisphere contrala teral to the weakness, but it may well be that areas nearby to the nor mal motor output areas can partially substitute, There is some evidenc e for increased corticospinal tract activity originating ipsilateral t o the hemiplegia in patients, but this may actually be associated with worse recovery. Patterns of use can influence cortical organization a nd should play a valuable role in rehabilitation. Certain drugs may af fect this process either positively or negatively. (C) 1998 Elsevier S cience Ireland Ltd.