Article

Interhemispheric inhibition might be a beneficial cortico-cortical
interaction, but also might be maladaptive in people with neurological disorders.
One recently revisited technique that has been shown to be effective in improving
motor function in people with stroke using interhemispheric modulation is
transcranial direct current stimulation (tDCS). OBJECTIVE: The aim of this study
was to investigate the effects of tDCS combined with unilateral motor training
with contralateral hand restraint on interhemispheric inhibition between the
dominant and nondominant hemispheres of the brain and on motor performance in
participants who were healthy. DESIGN: This was a double-blind, prospective,
single-center study with participants who were healthy. METHODS: Twenty
participants who were healthy were randomly assigned to receive either active or
sham tDCS of the primary motor cortex (M1) bilaterally combined with unilateral
motor training and contralateral hand restraint. A blinded rater assessed motor
function and cortical excitability, including assessment of transcallosal
inhibition (TCI). RESULTS: There was a larger increase in motor performance in
the nondominant hand for the active tDCS group compared with the sham tDCS group.
In addition, a decrease in cortical excitability in the dominant hemisphere and a
decrease in TCI from the dominant to nondominant hemisphere were observed for the
active tDCS group only. The TCI decrease in the active tDCS group was correlated
with motor performance improvement for the nondominant hand. Limitations
Limitations of this study included missing the effect of intracortical inhibition
due to a floor effect, not using the optimal tDCS montage, and not being able to
assess the effects of other variables such as gender due to the small sample
size. CONCLUSIONS: The results indicate that tDCS enhances the effects of
unilateral motor training and contralateral hand restraint on motor function, and
this benefit is associated with a different mechanism of action characterized by
bihemispheric modulation in which TCI from the dominant to the nondominant
hemisphere is decreased. Transcranial direct current stimulation might be a
useful tool to enhance the motor effects of constraint-induced movement therapy.

Langue : ANGLAIS