Background and Purpose-Injury-induced cortical reorganization is a widely recognized phenomenon. In contrast, there is almost no information on treatment-induced plastic changes in the human brain. The aim of the present study was to evaluate reorganization in the motor cortex of stroke patients that was induced with an efficacious rehabilitation treatment. Methods-We used focal transcranial magnetic stimulation to map the cortical motor output area of a hand muscle on both sides in 13 stroke patients in the chronic stage of their illness before and after a 12-day-period of constraint-induced movement therapy. Results-Before treatment, the cortical representation area of the affected hand muscle was significantly smaller than the contralateral side. After treatment, the muscle output area size in the affected hemisphere was significantly enlarged, corresponding to a greatly improved motor performance of the paretic limb. Shifts of the center of the output map in the affected hemisphere suggested the recruitment of adjacent brain areas. In follow-up examinations up to 6 months after treatment, motor performance remained at a high level, whereas the cortical area sizes in the 2 hemispheres became almost identical, representing a return of the balance of excitability between the 2 hemispheres toward a normal condition. Conclusions-This is the first demonstration in humans of a long-term alteration in brain function associated with a therapy-induced improvement in the rehabilitation of movement after neurological injury. Key Words: plasticity, neuronal Ⅲ transcranial magnetic stimulation Ⅲ reorganization Ⅲ physical therapy Ⅲ stroke R esearch with animals has led to the discovery that cortical reorganization occurs after injury to the nervous system. 1-3 Spontaneously occurring cortical reorganization phenomena that result from nervous system damage or conditions that involve abnormal sensory input have been shown to be associated with pathological states in humans; these include phantom limb pain, 4 tinnitus, 5 and focal hand dystonia. 6 After motor stroke, a complex pattern of reorganization has been described. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] In the subacute stage after a stroke, a reduction in motor cortex excitability and a decrease in the cortical representation area of paretic muscles have been found to occur. 17,19 This may represent a disadvantageous reorganization associated with an impaired motor function and could be due to the damage of neuronal structures or could reflect the disuse of the affected limb. 21,22 In addition to injury-related cortical reorganization, there is a second kind of process, use-dependent cortical reorganization, that results from the increased use of body parts in behaviorally relevant tasks and leads to an enhancement of the representation of those body parts in the cerebral cortex. 21,[23][24][25][26] It is possible that this process could be used to remediate pathological symptoms through the reversal or elimination of disadvantageous cortical reorganizat...

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Background and Purpose-Constraint-induced movement therapy (CI therapy) has previously been shown to produce large improvements in actual amount of use of a more affected upper extremity in the "real-world" environment in patients with chronic stroke (ie, Ͼ1 year after the event). This work was carried out in an American laboratory. Our aim was to determine whether these results could be replicated in another laboratory located in Germany, operating within the context of a healthcare system in which administration of conventional types of physical therapy is generally more extensive than in the United States. Methods-Fifteen chronic stroke patients were given CI therapy, involving restriction of movement of the intact upper extremity by placing it in a sling for 90% of waking hours for 12 days and training (by shaping) of the more affected extremity for 7 hours on the 8 weekdays during that period. Results-Patients showed a significant and very large degree of improvement from before to after treatment on a laboratory motor test and on a test assessing amount of use of the affected extremity in activities of daily living in the life setting (effect sizes, 0.9 and 2.2, respectively), with no decrement in performance at 6-month follow-up. During a pretreatment control test-retest interval, there were no significant changes on these tests. Conclusions-Results replicate in Germany the findings with CI therapy in an American laboratory, suggesting that the intervention has general applicability. (Stroke. 1999;30:586-592.)