F. Coroian

Somatosensory-Related Limitations for Bimanual Coordination After Stroke

Background. Bimanual coordinated movements may be impaired after stroke, so an assessment of causes is necessary to optimize rehabilitation strategies. Objective. We assessed the role of afference-based sources of coordination, including phase entrainment and error correction based on visual and somatosensory feedback. Methods. In all, 10 persons with unilateral chronic stroke and 8 age-matched controls participated in a kinesthetic tracking protocol, in which the hemiparetic upper limb was passively driven by the machine. The task consisted of matching the trajectory of the driven limb as accurately as possible with the freely moving limb in 2 conditions: eyes closed and eyes open. We analyzed the continuous relative phase (CRP), the mean absolute difference between positions (ADP) between the positions of the 2 limbs, and the jerk of the matching limb. Results. Coordination instability (CRP standard deviation) and mean ADP were significantly higher for patients with eyes closed, compared with patients with eyes open, controls with eyes closed, and controls with eyes open. Moreover, the jerk was higher for the nonparetic limb of patients than for the control group. Thus, the nonparetic limb did not produce optimally smooth movements even as the motor-driven paretic limb did. Conclusion. Besides deficits caused by interhemispheric competition and motor execution of the paretic limb, somatosensory feedback is a limiting factor in bimanual coordination after stroke. The findings have clinical implications pertaining to the design and individualization of efficient bimanual movement therapy.

Upper Limb Isokinetic Strengthening Versus Passive Mobilization in Patients With Chronic Stroke: A Randomized Controlled Trial

OBJECTIVE To assess the benefit of isokinetic strengthening of the upper limb (UL) in patients with chronic stroke as compared to passive mobilization. DESIGN Randomized blinded assessor controlled trial. SETTING Physical Medicine and Rehabilitation departments of 2 university hospitals. PARTICIPANTS Patients (N=20) with incomplete hemiplegia (16 men; mean age, 64y; median time since stroke, 32mo). INTERVENTIONS A 6-week comprehensive rehabilitation program, 3d/wk, 3 sessions/d. In addition, a 45-minute session per day was performed using an isokinetic dynamometer, with either isokinetic strengthening of elbow and wrist flexors/extensors (isokinetic strengthening group) or passive joint mobilization (control group). MAIN OUTCOME MEASURES The primary endpoint was the increase in Upper Limb Fugl-Meyer Assessment (UL-FMA) score at day 45 (t1). Secondary endpoints were increases in UL-FMA scores, Box and Block Test scores, muscle strength, spasticity, and Barthel Index at t1, t2 (3mo), and t3 (6mo). RESULTS Recruitment was stopped early because of excessive fatigue in the isokinetic strengthening group. The increase in UL-FMA score at t1 was 3.5±4.4 in the isokinetic strengthening group versus 6.0±4.5 in the control group (P=.2). Gains in distal UL-FMA scores were larger (3.1±2.8) in the control group versus 0.6±2.5 in the isokinetic strengthening group (P=.05). No significant group difference was observed in secondary endpoints. Mixed models confirmed those results. Regarding the whole sample, gains from baseline were significant for the UL-FMA at t1 (+4.8; P<.001), t2, and t3 and for the Box and Block Test at t1 (+3; P=.013) and t2. CONCLUSIONS In a comprehensive rehabilitation program, isokinetic strengthening did not show superiority to passive mobilization for UL rehabilitation. Findings also suggest a sustained benefit in impairments and function of late UL rehabilitation programs for patients with stroke.