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Upper limb function is a high priority for people with cervical spinal cord injury (SCI). This case report describes an application of technology to activate spared neural pathways and improve wrist motor control. A 73-year-old man with chronic incomplete C5 SCI completed 24 training sessions over 92 days. Each session included 2 maximal contractions, 6 test trials, and 10 training trials of a visuomotor force tracking task. The participant attempted to match a sinusoidal target force curve, using isometric wrist flexor and extensor contractions. Electromyography (EMG) and force signals were recorded. Errors were elevated initially and improved with training, similarly during extension and flexion phases of the force tracking task. Improvement in both phases was associated with greater flexor activation in flexion phases and greater extensor relaxation in flexion phases. Errors were not related to EMG modulation during the extensor phases. Small improvements in active range of motion, grip force, spasticity, touch sensation, and corticospinal excitability were also observed. Motor skill training improved motor control after incomplete SCI, within the range of residual force production capacity. Performance gains were associated with specific adjustments in muscle activation and relaxation, and increased corticospinal excitability. [ABSTRACT FROM AUTHOR]

This study investigated whether grip type and/or task goal influenced reaching and grasping performance in poststroke hemiparesis. Sixteen adults with poststroke hemiparesis and twelve healthy adults reached to and grasped a cylindrical object using one of two grip types (3-finger or palmar) to achieve one of two task goals (hold or lift). Performance of the stroke group was characteristic of hemiparetic limb movement during reach-to-grasp, with more curved handpaths and slower velocities compared with the control group. These effects were present regardless of grip type or task goal. Other measures of reaching (reach time and reach velocity at object contact) and grasping (peak thumb-index finger aperture during the reach and peak grip force during the grasp) were differentially affected by grip type, task goal, or both, despite the presence of hemiparesis, providing new evidence that changes in motor patterns after stroke may occur to compensate for stroke-related motor impairment. [ABSTRACT FROM AUTHOR]

Background: Previous studies have suggested that practicing functional tasks bilaterally instead of unilaterally may improve paretic limb performance after stroke. Objective: The purposes of this study were to determine whether the bilateral movement condition alters paretic limb performance of a functional task in people with poststroke hemiparesis and to identify specifically which parameters of performance may be affected. Methods: In this single-session study, we examined immediate effects of the bilateral versus unilateral movement condition on performance of a reach-grasp-lift-release task at preferred speed in 16 people with mild to moderate poststroke hemiparesis and in 12 healthy control subjects. Performance was quantified by using motion analysis variables, including duration of the reach and grasp phases, reach path straightness, maximum thumb-index finger aperture, efficiency of finger movement, peak grip force, and timing of release. Results: We found no evidence of immediate improvement in paretic limb performance in the bilateral condition. In both groups, release timing occurred later when participants moved bilaterally instead of unilaterally, possibly representing a divided attention effect. Other variables did not differ across conditions. Conclusions: Our findings suggest little immediate impact of the bilateral condition on motor performance of a reach-grasp-lift-release task at preferred speed in people with mild to moderate hemiparesis. [ABSTRACT FROM AUTHOR]

Background. Although slow and insufficient muscle activation is a hallmark of hemiparesis poststroke, movement speed is rarely emphasized during upper-extremity rehabilitation. Moving faster may increase the intensity of task-specific training, but positive and/or negative effects on paretic-limb movement quality are unknown. Objective. To determine whether moving quickly instead of at a preferred speed either enhances or impairs paretic-limb task performance after stroke. Methods. A total of 16 people with poststroke hemiparesis and 11 healthy controls performed reach–grasp–lift movements at their preferred speed and as fast as possible, using palmar and 3-finger grip types. The authors measured durations of the reach and grasp phases, straightness of the reach path, thumb–index finger separation (aperture), efficiency of finger movement, and grip force. Results. Reach and grasp phase durations decreased in the fast condition in both groups, showing that participants were able to move more quickly when asked. When moving fast, the hemiparetic group had reach durations equal to those of healthy controls moving at their preferred speed. Movement quality also improved. Reach paths were straighter, and peak apertures were greater in both groups in the fast condition. The group with hemiparesis also showed improved efficiency of finger movement. Differences in peak grip force across speed conditions did not reach significance. Conclusions. People with hemiparesis who can perform reach–grasp–lift movements with a 3-finger grip can move faster than they choose to, and when they do, movement quality improves. Simple instructions to move faster could be a cost-free and effective means of increasing rehabilitation intensity after stroke. [ABSTRACT FROM PUBLISHER]