Beyond stroke: impact of the lesion side on the recovery of between-hands coordination.

Dr Julien METROTa, Prof Denis MOTTETb, Dr Jérome FROGERc, Prof Isabelle LAFFONTd

a Movement to Health, Université de Montpellier, b Movement to Health, Université de Montpellier, France, c Département MPR Le Grau du Roi, CHU Nîmes, France / Movement to Health, Université de Montpellier, France, d Département MPR, CHRU Montpellier, France / Movement to Health, Université de Montpellier, France

Objective. One-fit-all post-stroke rehabilitation has limited plausibility. Better understanding the effects of the lesion location on the recovery process may help to develop new tailored therapeutic strategies to individuals. The purpose of this study was to assess the natural evolution of bimanual coordination over standard rehabilitation according to the lesion side, aiming to identify a potential responder-profile for bimanual-oriented therapy.

Material/Patients. 12 hemiparetic, moderately impaired patients were included within 30 days after a first unilateral stroke. The kinematic and clinical assessments were performed once a week for 6 weeks and at 3 months after inclusion. The patients performed a reach-to-grasp task in unimanual condition followed by a synchronous bimanual condition. The clinical evaluation included the Fugl-Meyer Assessment, Box and Block test, 9-Hole Peg test and Barthel Index.

Results. The clinical scores indicated no difference in motor function between left- (LHD) and right-hemispheric damaged (RHD) patients over time. Interestingly, the LHD patients produced smoother bimanual reaching movements than the RHD patients while we found no effect of the lesion side on reaching kinematics of the paretic UL in unimanual condition. These inter-group differences disappeared after 5 weeks of standard therapy, likely indicating a time lag in motor recovery.

Discussion. Because the RHD patients were less prematurely coordinated again during bimanual movements than the LHD patients, they may benefit differently from a bimanual rehabilitation, and especially from the simultaneous involvement of the ipsilesional UL. It becomes necessary to investigate to what extent this difference due to lesion side may be integrated into the design of rehabilitation protocols.

Keywords : Between-hands coordination, hemispheric lateralization, stroke recovery, reach-to-grasp, kinematics.