Article

Low-frequency repetitive transcranial magnetic stimulation (rTMS)
over the unaffected motor cortex may improve motor function of the paretic hand
after stroke. However, low-frequency rTMS might adversely affect bimanual
movement by decreasing transcallosal function.
The authors
investigated whether combined administration of rTMS and transcranial direct
current stimulation (tDCS) prevents deterioration of bimanual movement induced by
low-frequency rTMS over the unaffected hemisphere. METHODS: A total of 27
participants with chronic subcortical stroke were randomly assigned to receive
either 1 Hz rTMS over the unaffected hemisphere, anodal tDCS over the affected
hemisphere, or a combination of rTMS and tDCS. All patients performed a pinching
motor-training task after stimulation. Bimanual movement and transcallosal
inhibition (TCI) were evaluated after stimulation.
RESULTS: rTMS and rTMS-tDCS
enhanced the motor training effect on the paretic hand. rTMS decreased bimanual
coordination and reduced TCI from the unaffected to the affected hemisphere
(TCI(unaff-aff)). rTMS-tDCS changed TCI balance of both hemispheres but did not
affect bimanual coordination or TCI(unaff-aff). The change in bimanual
coordination was negatively correlated with TCI(unaff-aff). Following
stimulation, improvement in the pinch force in the paretic hand was negatively
correlated with TCI balance. CONCLUSIONS: Inhibitory rTMS over the unaffected
hemisphere transiently caused deterioration of bimanual movements for the current
task in stroke patients. This short-term decline was prevented by combined
administration of low-frequency rTMS over the unaffected hemisphere and anodal
tDCS over the affected hemisphere. These responses to bihemispheric stimulation
suggest possible caution and opportunities for the rehabilitation of hand function after stroke.

Langue : ANGLAIS