vendex and Cerebral-Hemorrhage

The aim of this paper was to explore how an upper limb exoskeleton can be programmed to impose specific joint coordination patterns during rehabilitation. Based on rationale which emphasizes the importance of the quality of movement coordination in the motor relearning process, a robot controller was developed with the aim of reproducing the individual corrections imposed by a physical therapist on a hemiparetic patient during pointing movements. The approach exploits a description of the joint synergies using principal component analysis (PCA) on joint velocities. This mathematical tool is used both to characterize the patient's movements, with or without the assistance of a physical therapist, and to program the exoskeleton during active-assisted exercises. An original feature of this controller is that the hand trajectory is not imposed on the patient: only the coordination law is modified. Experiments with hemiparetic patients using this new active-assisted mode were conducted. Obtained results demonstrate that the desired inter-joint coordination was successfully enforced, without significantly modifying the trajectory of the end point.

Topics: Adult; Aged; Algorithms; Biomechanical Phenomena; Brain Damage, Chronic; Brain Ischemia; Cerebral Hemorrhage; Data Interpretation, Statistical; Female; Hand; Humans; Joints; Learning; Male; Middle Aged; Motor Skills; Neuronal Plasticity; Paresis; Principal Component Analysis; Psychomotor Performance; Robotics; Stroke; Stroke Rehabilitation; Torque; Upper Extremity

To better understand the mechanisms behind fatigue in muscles affected by a neuromuscular disease.. Patients recruited by convenience compared to age-matched healthy subjects from a population study.. University hospital laboratory.. Repetitive eccentric-concentric plantar flexions at 60 degrees/sec were performed on a dynamometer until exhaustion. The mean power frequency and root mean square of the electromyogram were recorded, and work was calculated.. Both legs of seven patients with upper motor neuron lesion from stroke and one leg of healthy men were tested.. There were no significant (p > .05) differences in number of cycles performed or decrease of work between any of the tested legs. There was a significant (p > .05) difference in work performed by the affected leg and the reference group. Mean power frequency decreased significantly (p > .05) for the gastrocnemius muscle in the nonaffected leg and for the reference group, while no such decreases were found in the affected leg. The statistical methods used were the nonparametric tests: the Wilcoxon one-sample for differences between paired observations, and the Mann-Whitney U for differences between groups.. A reduction in work in high-intensity dynamic muscle activity may not be associated with a reduction in mean power frequency, especially in patients with altered supraspinal control. There may be peripheral fatigue factors not reflected in the electromyographic activity.

Topics: Brain Infarction; Case-Control Studies; Cerebral Hemorrhage; Electromyography; Humans; Isotonic Contraction; Leg; Male; Middle Aged; Muscle Fatigue; Range of Motion, Articular; Risk Factors; Signal Processing, Computer-Assisted; Statistics, Nonparametric; Stroke; Torque