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ALTHOUGH phantom-limb pain is a frequent consequence of the amputation of an extremity, little is known about its origin l -4.On the basis of the demonstration of substantial plasticity of the somatosensory cortex after amputationS or somatosensory deafferentation in adult monkeys6, it has been suggested that cortical reorganization could account for some non-painful phantom-limb phenomena in amputees and that cortical reorganization has an adaptive (that is, pain-preventing) function 2 ,s,7,8. Theoretical and empirical work on chronic back pain 9 ,lo has revealed a positive relationship between the amount of cortical alteration and the magnitude of pain, so we predicted that cortical reorganization and phantom-limb pain should be positively related. Using non-invasive neuromagnetic imaging techniques to determine cortical reorganization in humans ll -13, we report a very strong direct relationship (r = 0.93) between the amount of cortical reorganization and the magnitude of phantom limb pain (but not non-painful phantom phenomena) experienced after arm amputation. These data indicate that phantom-limb pain is related to, and may be a consequence of, plastic changes in primary somatosensory cortex.A brief telephone interview was used to obtain information about the amount of phantom-limb pain in 65 upper-limb ampu-482 tees. This information served as the sole basis for the selection of a representative sample of 13 subjects with widely varying degrees of phantom-limb pain. The mean age of the 13 subjects was 50.1 years (s.d. = 17,2, range 27-73 yr), mean post-amputation time was 24.3 years (s.d. = 19.8, range I to 51 yr). Twelve men and one woman participated in the study, Traumatic injury in ten cases and osteosarcoma in three cases had made the amputation necessary. Cortical reorganization was determined by magnetic source imaging' , using the method illustrated in Fig. 1. The subjects underwent a comprehensive neurological and psychological investigation which included detailed assessments of phantom pain and phantom sensations, stump pain and stump sensations, pre-amputation pain, telescoping (the subjective experience of the phantom limb retracting towards and often disappearing in the stump), and facial remapping (the appearance of phantom sensations upon non-painful stimulation of the face with isomorphism between facial stimulation sites and the location of phantom sensations) (Fig. 2 legend).A large significant positive linear relationship was found between the amount of phantom-limb pain, as measured on the standardized pain-intensity scale, and the amount of cortical reorganization (r=0.93, P

Magnetic source imaging revealed that the cortical representation of the digits of the left hand of string players was larger than that in controls. The effect was smallest for the left thumb, and no such differences were observed for the representations of the right hand digits. The amount of cortical reorganization in the representation of the fingering digits was correlated with the age at which the person had begun to play. These results suggest that the representation of different parts of the body in the primary somatosensory cortex of humans depends on use and changes to conform to the current needs and experiences of the individual.Evidence has accumulated over the past rwo decades that indicares that alterations in afferent input can induce plastic reorganizational ch

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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...

Abstract-Patients with chronic aphasia were assigned randomly to a group to receive either conventional aphasia therapy or constraint-induced (CI) aphasia therapy, a new therapeutic technique requiring intense practice over a relatively short period of consecutive days. CI aphasia therapy is realized in a communicative therapeutic environment constraining patients to practice systematically speech acts with which they have difficulty. Patients in both groups received the same amount of treatment (30 to 35 hours) as 10 days of massed-practice language exercises for the CI aphasia therapy group (3 hours per day minimum; 10 patients) or over a longer period of Ϸ4 weeks for the conventional therapy group (7 patients). CI aphasia therapy led to significant and pronounced improvements on several standard clinical tests, on self-ratings, and on blinded-observer ratings of the patients' communicative effectiveness in everyday life. Patients who received the control intervention failed to achieve comparable improvements. Data suggest that the language skills of patients with chronic aphasia can be improved in a short period by use of an appropriate massed-practice technique that focuses on the patients' communicative needs. (Stroke. 2001;32:1621-1626.)

After limited sensory deafferentations in adult primates, somatosensory cortical maps reorganize over a distance of 1 to 2 millimeters mediolaterally, that is, in the dimension along which different body parts are represented. This amount of reorganization was considered to be an upper limit imposed by the size of the projection zones of individual thalamocortical axons, which typically also extend a mediolateral distance of 1 to 2 millimeters. However, after extensive long-term deafferentations in adult primates, changes in cortical maps were found to be an order of magnitude greater than those previously described. These results show the need for a reevaluation of both the upper limit of cortical reorganization in adult primates and the mechanisms responsible for it.

Pediatric CI therapy produced major and sustained improvement in motoric function in the young children with hemiparesis in the study.