Speed-dependent reductions of force output in people with poststroke hemiparesis.
(25/797)
BACKGROUND AND PURPOSE: Movement is slow in people with poststroke hemiparesis. Moving at faster speeds is thought by some researchers to exacerbate abnormal or unwanted muscle activity. The purpose of this study was to quantify the effects of increased speed on motor performance during pedaling exercise in people with poststroke hemiparesis. SUBJECTS: Twelve elderly subjects with no known neurological impairment and 15 subjects with poststroke hemiparesis of greater than 6 months' duration were tested. METHODS: Subjects pedaled at 12 randomly ordered workload and cadence combinations (45-, 90-, 135-, and 180-J workloads at 25, 40, and 55 rpm). Pedal reaction forces were used to calculate work done by each lower extremity. Electromyographic activity was recorded from 7 lower-extremity muscles. RESULTS: The main finding was that net mechanical work done by the paretic lower extremity decreased as speed increased in all subjects. The occurrence of inappropriate muscle activity on the paretic side, however, was not exacerbated in that the vastus medialis muscle on the paretic side did not show a consistent further increase in its prolonged activity at higher speeds. The mechanics of faster pedaling resulted in greater net negative mechanical work because, at higher pedaling rates, the prolonged vastus medialis muscle activity is present during a greater portion of the cycle. CONCLUSION AND DISCUSSION: The lessened force output by the paretic limb is mainly the result of the inherent mechanical demands of higher-speed pedaling and not due to exacerbation of impaired neural control. (+info)
Restoration of shoulder movement in quadriplegic and hemiplegic patients by functional electrical stimulation using percutaneous multiple electrodes.
(26/797)
The purpose of this study is to restore the motion of the paralyzed shoulder caused by upper motor neuron disorders using functional electrical stimulation (FES). Percutaneous wire electrodes were implanted into twelve muscles of the shoulder in six patients with stroke or cervical spinal cord injury. The motion of the paralyzed shoulder was controlled by a portable FES computer system, with the three standard stimulation patterns for restoring motion of 90 degrees flexion to 90 degrees horizontal abduction, 90 degrees flexion to 20 degrees horizontal adduction, and 90 degrees abduction to 90 degrees horizontal adduction. Shoulder movements were repeatedly controlled according to the created stimulation patterns in five of the patients. The two dimensional motion analyzer also confirmed shoulder control over a satisfactorily broad range of excursion. One hemiplegic patient, who was a signboard painter, had his paretic left upper extremity improved by FES, and he drew a large picture on a board with his normal right hand and, with his affected left arm against the wall, to support his trunk. This may be a world first case of producing shoulder motion through FES. (+info)
Electromyographic study relating to shoulder motion: control of shoulder joint by functional electrical stimulation.
(27/797)
The purpose of this study is to create the standard stimulation patterns of shoulder motion from electromyographic (EMG) data in 13 healthy human volunteers in order to control the movement of the paralyzed shoulder in quadriplegic and hemiplegic patients by functional electrical stimulation (FES). Simultaneous EMG measurement was made at 24 points of 17 major muscles relating to shoulder motion. Since the number of the output channels in the portable FES apparatus is limited, 12 major muscles were selected from statistically processing these EMG data and stimulation patterns were created based on the EMG data of these muscles. Thus three standard stimulation patterns were created to move the shoulder, i.e., (i) 90 degrees flexion to 90 degrees horizontal abduction, (ii) 90 degrees flexion to 20 degrees horizontal adduction, and (iii) 90 degrees abduction to 90 degrees horizontal adduction. With the created stimulation patterns, the restoration of the shoulder motion in plegic patients was successful and it will be reported in the next paper. (+info)
Perception of self-generated movement following left parietal lesion.
(28/797)
Three apraxic patients with lesions in the left parietal cortex were required to execute finger movements with either hand, while the visual feedback they received about the movement was manipulated systematically. We used a device which allowed us to present on a video monitor either the patient's hand or the examiner's hand simultaneously performing an identical or a different movement. In each trial, patients were required to decide whether the hand shown on the screen was their own or not. Hand movements produced in response to verbal command included simple (single-finger extension) and complex gestures (multi-finger extension). Ownership judgements were analysed and compared with those produced by six normal controls and two non-apraxic neurological patients. Apraxic patients and controls accurately recognized their own hand on the screen (own movement condition) and correctly identified the viewed hand as the examiner's when it performed a movement different from their own movement (incongruent movement condition). However, when the viewed hand was the examiner's hand executing their own movement (congruent movement condition), apraxic patients were significantly more impaired than controls. When the results were analysed as a function of gesture type, the number of correct responses was significantly lower for apraxic patients with respect to controls only for complex gestures. Interestingly, when patients executed the finger gestures inaccurately, they still failed to recognize the examiner's hand as alien, and claimed that the correct movement presented on the screen was their own. These results confirm that parietal lesions alter the representational aspects of gestures, and suggest a failure in evaluating and comparing internal and external feedback about movement. We conclude that the parietal cortex plays an important role in generating and maintaining a kinaesthetic model of ongoing movements. (+info)
Balloon angioplasty for embolic total occlusion of the middle cerebral artery and ipsilateral carotid stenting in an acute stroke stage.
(29/797)
A 66-year-old man suffering from neurologic symptoms caused by acute embolic total occlusion of the left middle cerebral artery was treated successfully with balloon angioplasty, and an ipsilateral carotid stenosis subsequently was dilated with stenting. The patient's clinical outcome 30 days later was favorable. This therapeutic option may prove to be a useful means of treating a patient with acute stroke, embolic total occlusion of the middle cerebral artery, and an ipsilateral carotid stenosis. (+info)
Forced use of the upper extremity in chronic stroke patients: results from a single-blind randomized clinical trial.
(30/797)
BACKGROUND AND PURPOSE: Of all stroke survivors, 30% to 66% are unable to use their affected arm in performing activities of daily living. Although forced use therapy appears to improve arm function in chronic stroke patients, there is no conclusive evidence. This study evaluates the effectiveness of forced use therapy. METHODS: In an observer-blinded randomized clinical trial, 66 chronic stroke patients were allocated to either forced use therapy (immobilization of the unaffected arm combined with intensive training) or a reference therapy of equally intensive bimanual training, based on Neuro-Developmental Treatment, for a period of 2 weeks. Outcomes were evaluated on the basis of the Rehabilitation Activities Profile (activities), the Action Research Arm (ARA) test (dexterity), the upper extremity section of the Fugl-Meyer Assessment scale, the Motor Activity Log (MAL), and a Problem Score. The minimal clinically important difference (MCID) was determined at the onset of the study. RESULTS: One week after the last treatment session, a significant difference in effectiveness in favor of the forced use group compared with the bimanual group (corrected for baseline differences) was found for the ARA score (3.0 points; 95% CI, 1.3 to 4.8; MCID, 5.7 points) and the MAL amount of use score (0.52 points; 95% CI, 0.11 to 0.93; MCID, 0.50). The other parameters revealed no significant differential effects. One-year follow-up effects were observed only for the ARA. The differences in treatment effect for the ARA and the MAL amount of use scores were clinically relevant for patients with sensory disorders and hemineglect, respectively. CONCLUSIONS: The present study showed a small but lasting effect of forced use therapy on the dexterity of the affected arm (ARA) and a temporary clinically relevant effect on the amount of use of the affected arm during activities of daily living (MAL amount of use). The effect of forced use therapy was clinically relevant in the subgroups of patients with sensory disorders and hemineglect, respectively. (+info)
Evolution of cortical activation during recovery from corticospinal tract infarction.
(31/797)
BACKGROUND AND PURPOSE: Recovery from hemiparesis due to corticospinal tract infarction is well documented, but the mechanism of recovery is unknown. Functional MRI (fMRI) provides a means of identifying focal brain activity related to movement of a paretic hand. Although prior studies have suggested that supplementary motor regions in the ipsilesional and contralesional hemisphere play a role in recovery, little is known about the time course of cortical activation in these regions as recovery proceeds. METHODS: Eight patients with first-ever corticospinal tract lacunes causing hemiparesis had serial fMRIs within the first few days after stroke and at 3 to 6 months. Six healthy subjects were used as controls. Statistically significant voxels during a finger-thumb opposition task were identified with an automated image processing program. An index of ipsilateral versus contralateral activity was used to compare relative contributions of the 2 hemispheres to motor function in the acute and chronic phases after stroke. RESULTS: Controls showed expected activation in the contralateral sensorimotor cortex (SMC), premotor, and supplementary motor areas. Stroke patients differed from control patients in showing greater activation in the ipsilateral SMC, ipsilateral posterior parietal, and bilateral prefrontal regions. Compared with the nonparetic hand, the ratio of contralateral to ipsilateral SMC activity during movement of the paretic hand increased significantly over time as the paretic hand regained function. CONCLUSIONS: The evolution of activation in the SMC from early contralesional activity to late ipsilesional activity suggests that a dynamic bihemispheric reorganization of motor networks occurs during recovery from hemiparesis. (+info)
Illusory limb movements in anosognosia for hemiplegia.
(32/797)
To clarify the relation between anosognosia for hemiplegia and confabulation, 11 patients with acute right cerebral infarctions and left upper limb hemiparesis were assessed for anosognosia for hemiplegia, illusory limb movements (ILMs), hemispatial neglect, asomatognosia, and cognitive impairment. Five of 11 patients had unequivocal confabulation as evidenced by ILMs. The presence of ILMs was associated with the degree of anosognosia (p = 0.002), with hemispatial neglect (p<0.05), and with asomatognosia (p<0.01). The results confirm that a strong relation exists between anosognosia for hemiplegia and confabulations concerning the movement of the plegic limb. There is also a strong relation between ILMs and asomatognosia. (+info)