Article

Investigations were performed to establish if
repetitive arm cycling training enhances the antispastic effect of intramuscular
botulinum toxin (BTX) injections in postischemic spastic hemiparesis. Effects on
cerebral activation were evaluated by functional magnetic resonance imaging
(fMRI). METHODS: Eight chronic spastic hemisyndrome patients (49 +/- 10 years)
after middle cerebral artery infarction (5.5 +/- 2.7 years)
were investigated.
BTX was injected into the affected arm twice, 6 months apart. Spasticity was
assessed using the Ashworth Scale and range of motion before and 3 months after
BTX injections. Images were analyzed using Brain Voyager QX 1.8, and fMRI signal
changes were corrected for multiple comparisons. RESULTS: During passive
movements of affected and nonaffected hands, fMRI activity was increased
bilaterally in the sensorimotor cortex (MISI), secondary somatosensory areas
(SII), and supplementary motor area predominantly in the contralesional
hemisphere, compared with the rest. Following repetitive arm cycling, fMRI
activity increased further in MISI of the lesioned hemisphere and SII of the
contralesional hemisphere. For patients with residual motor activity,
treatment-related fMRI activity increases were associated with reduced
spasticity; in completely plegic patients, there was no fMRI activity change in
SII but increased spasticity after training. CONCLUSION: Increased activity in
SII of the contralesional hemisphere and in MISI of the lesioned hemisphere
reflect a treatment-induced effect in the paretic arm. It is hypothesized that
the increased BOLD activity results from increased afferent information related
to the antispastic BTX effect reinforced by training.

Langue : ANGLAIS