Article

Poststroke, the ipsilesional upper limb shows slight but substantial
and long-term motor deficits. OBJECTIVE: To define brain activation patterns
during a gross motor flexion/extension task of the ipsilesional elbow early
poststroke before and after rehabilitation, in relation to the corresponding
kinematic characteristics at each time point. METHOD: Simultaneous analysis of
kinematic features (amplitude, frequency, smoothness, and trajectory of movement)
and of corresponding functional magnetic resonance imaging activations (block-design).
A total of 21 persons with subacute initial severe stroke
(Fugl-Meyer score <30/66) participated twice: within the first 2 months
poststroke (V0) and after 6 weeks of rehabilitation (V1). Results at both time
points were compared with activation patterns and kinematics of 13 healthy
controls. RESULTS: Compared with controls ( a) movements of the ipsilesional
upper-limb poststroke were smaller (V0 + V1) and less smooth (V0 + V1) and ( b)
participants poststroke showed additional recruitment of the contralesional
middle temporal gyrus (V0) and rolandic opercularis involved in movement
visualization (V0 + V1), whereas they lacked activation of the supramarginal
gyrus (V0 + V1). Over time, participants poststroke showed an extended activation
of the contralesional sensorimotor cortex at V0. CONCLUSION: Movements of the
ipsilesional upper limb within an initially severe stroke group were not only
atypical in motor outcome, but seemed to be controlled differently. Together the
observed changes pointed toward an overall disturbance of the bihemispheric motor
network poststroke, marked by
( a) a possible despecialization of the nondamaged
hemisphere and ( b) the employment of alternative control strategies to ensure
optimal task execution.

Langue : ANGLAIS