Hemiparetic Stroke Patients Research Articles

Advances in the Understanding and Treatment of Stroke Impairment Using Robotic Devices

The presence of robotic devices in rehabilitation centers is now becoming commonplace across the world, challenging heath care professionals to rethink treatment strategies for motor impairment in hemiparetic stroke patients. In this article, we will discuss some of the motivations for using these devices, review clinical outcomes following robotic-assisted training in both the upper and lower extremities, and detail how these devices can provide quantitative evaluations of function. We will also address the clinical issues that need to be considered when using robotic devices to treat stroke patients, and finally a vision of where this field is heading will be discussed.

An upper extremity kinematic model for evaluation of hemiparetic stroke

Quantification of rehabilitation progress is necessary for accurately assessing clinical treatments. A three-dimension (3D) upper extremity (UE) kinematic model was developed to obtain joint angles of the trunk, shoulder and elbow using a Vicon motion analysis system. Strict evaluation confirmed the system's accuracy and precision. As an example of application, the model was used to evaluate the upper extremity movement of eight hemiparetic stroke patients with spasticity, while completing a set of reaching tasks. Main outcome measures include kinematic variables of movement time, range of motion, peak angular velocity, and percentage of reach where peak velocity occurs. The model computed motion patterns in the affected and unaffected arms. The unaffected arm showed a larger range of motion and higher angular velocity than the affected arm. Frequency analysis (power spectrum) demonstrated lower frequency content for elbow angle and angular velocity in the affected limb when compared to the unaffected limb. The model can accurately quantify UE arm motion, which may aid in the assessment and planning of stroke rehabilitation, and help to shorten recovery time.

Long-lasting effects of paired associative stimulation in hemiparetic stroke patients

Purpose To establish whether motor point stimulation paired with repetitive transcranial magnetic stimulation (rTMS) produces a lasting modulation of the primary motor cortex in persons with hemiparetic stroke. Methods Subjects were nine hemiparetic patients after stroke, all right-handed. The mean days from onset were 80 days. Repeated measurements of the motor evoked potential (MEP) in the affected first dorsal inter osseous (FDI) muscle in all subjects were performed. For determination of baseline, a single measurement of the MEPs was given before intervention stimulation. Subjects received 30 min of just suprathreshold motor point stimulation of the affected abductor pollicis brevis (APB) muscle paired every 10 s with TMS over the motor cortex. After intervention stimulation, measures of MEPs were taken immediately (0 min) and at 10, 20 and 30 min. Results The MEPs significantly increased in amplitude immediately after pairing stimulation and recovered to baseline after 30 min in amplitude. Conclusions In stroke hemiparetic patients, as well as healthy subjects, paired stimulation increases the corticomotor excitability for short periods after stimulation. This finding might have potential therapeutic implications for stroke rehabilitation.

Comparison of the impact of a single session of isokinetic or isotonic muscle stretch on gait in patients with spastic hemiparesis

To establish if isokinetic and isotonic muscle stretch (with or without weight-bearing) of the ankle plantar flexors improves gait in hemiplegic patients. A further aim was to compare the effectiveness of these treatment methods. A randomized, parallel group prospective study. A stroke rehabilitation unit. Ambulatory hemiparetic stroke patients with mild to moderately severe muscle hypertonia of the lower limb and a group of healthy control subjects. Subjects were randomized to receive a single 20-min session of isokinetic muscle stretch or isotonic muscle stretch with or without weight-bearing. Selected kinematic, kinetic and spatio-temporal gait parameters were measured at baseline, immediately after the muscle stretch and 24 h later. Sixty-six patients and 21 healthy control subjects were recruited and completed the study. There were statistically significant differences between the patient groups and the healthy subjects on most of the gait parameters studied. However, the differences between the patient groups or between the three measurements over time for each type of muscle stretch did not reach statistical significance. A single session of isokinetic or isotonic muscle stretch (with or without weight-bearing) of the ankle plantar flexors has no clinically observable effect on the gait of hemiplegic stroke patients.

Incidence and diagnosis of anosognosia for hemiparesis revisited

Background: In previous studies, the incidence of anosognosia for hemiparesis has varied between 17% and 58% in samples of brain damaged patients with hemiparesis. Objective: To determine whether this wide...

Bi‐hemispheric contribution to functional motor recovery of the affected forelimb following focal ischemic brain injury in rats

In many recovering hemiparetic stroke patients, movement of the affected limb elicits ipsilateral activation of sensorimotor areas within the undamaged hemisphere, which is not observed in control subjects. Following middle cerebral artery occlusion, rats received intensive enriched-rehabilitation (ER) of the impaired forelimb for 4 weeks. Weekly assessments on a skilled reaching test demonstrated significant improvement in ischemic animals over 4 weeks of ER (P < 0.05). We hypothesized that if the undamaged forelimb motor cortex contributed to improved forelimb function, then inhibition of neural activity within this region should reinstate (at least some of) the initial motor impairment. After 3 and 4 weeks of ER, animals received a microinjection of lidocaine hydrochloride into the undamaged motor cortex and were re-assessed on reaching ability. The behavioral effect of lidocaine challenge was dependent on the size of the infarct: animals with large infarcts were rendered unable to retrieve any food pellets and had great difficulty even contacting a pellet with the affected forepaw. Small-infarct animals were only moderately affected (25% reduction in success) by lidocaine, an effect similar to that observed in control animals. Qualitative assessments of recovered reaching after 4 weeks of rehabilitation revealed that impairments in forelimb lift, advance and aim were exacerbated (P < 0.05) following lidocaine-inactivation of the undamaged motor cortex of animals with large ischemic infarcts. In animals with small infarcts, lidocaine challenge only impaired limb advance. Thus, recruitment of the undamaged hemisphere may depend on the functional integrity of the remaining sensorimotor system. These data suggest that, in the rat, the undamaged (ipsilateral) motor system may contribute to compensatory recovery of the affected forelimb.

Unilateral Impairment of Leg Blood Flow in Chronic Stroke Patients

Background: Previous studies comparing paretic limb blood flow with the unaffected limb have been contradictory and have often omitted comparisons of peak reactive hyperemic flow. Our objective was to perform bilateral measurements of resting and reactive hyperemic blood flow in the lower legs of chronic (>6 months) stroke patients. A secondary purpose was to determine the extent to which any unilateral changes in limb blood flow were a function of decreases in lean tissue mass on the affected side. We hypothesized that the chronic hemiparesis accompanying ischemic stroke creates an altered metabolic environment in the tissues of the affected side that ultimately impairs vasomotor function. Methods: The study used a single-visit cross-sectional design. All tests were performed at the Baltimore VA Medical Center. Nineteen chronic hemiparetic stroke patients (15 male, 4 female) who had mild to moderate hemiparetic gait after ischemic stroke were recruited for observation. Bilateral measurements of resting and reactive hyperemic blood flow were made using venous occlusion strain gauge plethysmography. Paired t-tests were used for the between leg comparison. Regression analysis and analysis of covariance were utilized to determine the strength of the relationship between lower leg lean tissue mass and blood flow. Results: Resting and reactive hyperemic blood flows were significantly reduced in the paretic compared with the non-paretic limb (32 and 35%, respectively, p < 0.001). Lean tissue mass was also significantly lower in the affected limb (p < 0.01). However, neither resting nor reactive hyperemic blood flows were significantly correlated with lower leg lean tissue mass by dual energy X-ray absorptiometry. The difference in blood flow between limbs remained after covarying for lean tissue mass. Conclusion: Hemiparesis causes impairments in vasomotor function under both resting and hyperemic conditions that are independent of the muscle atrophy on the affected side.

Poststroke “Pushing”

Patients with hemiparetic stroke have impaired balance control. Some patients ("pushers") are resistant to accepting weight on and actively "push" away from the nonparetic side. This research identified pushers from stroke patients with moderate to severe hemiparesis and examined longitudinal changes in symptoms, level of impairment, and functional independence. Prospective sample of hemiparetic stroke patients (n=65) located in Toronto, Canada. Detailed clinical assessments were performed within 10 days postonset, at 6 weeks, and at 3 months. At 1 week after stroke, 63% of patients demonstrated features of pushing. In 62% of pushers, symptoms resolved by 6 weeks, whereas in 21%, pushing symptoms persisted at 3 months. Motor recovery and functional abilities at 3 months were significantly lower among the pushers compared with the nonpushers. Pushers also had a significantly longer hospital length of stay (89 days versus 57 days). It is noteworthy that motor and functional recovery improved significantly over the 3-month study period for both pushers and nonpushers. Identification of stroke patients with pushing symptoms has prognostic implications for recovery. In light of this potential recovery, rehabilitation specialists need to refine treatment approaches for the pushers to further improve functional outcome.

The Contribution of Cervical Propriospinal Premotoneurons in Recovering Hemiparetic Stroke Patients

There is evidence in humans that the C3/4 level of the spinal cord is a site for sensorimotor integration, analogous to the C3/4 propriospinal system (PS) in cat. Although the clinical relevance of the putative C3/4 PS in humans is not clear, there is some evidence indicating that drive to upper limb muscles via this nonmonosynaptic pathway is upregulated as a compensatory mechanism in stroke and in Parkinson's disease. The authors investigated whether descending drive via the C3/4 PS to affected limb wrist flexors of moderately to well-recovered chronic stroke patients is upregulated compared with controls. The extent of descending drive via the C3/4 PS was assessed in seven patients and seven control subjects during the onset of cocontraction of the biceps brachii and flexor carpi radialis (FCR), during which transcranial magnetic stimulation was used to evoke motor potentials in FCR. Responses were conditioned by subthreshold stimulation of the musculocutaneous nerve. The extent of this facilitation was taken as a measure of the proportion of drive to FCR motoneurons being transmitted via the C3/4 PS. Patients revealed greater facilitation than control subjects, suggesting that descending drive to forearm flexors was being transmitted via the C3/4 PS as a compensation mechanism after stroke.

Incidence and diagnosis of anosognosia for hemiparesis revisited

Background: In previous studies, the incidence of anosognosia for hemiparesis has varied between 17% and 58% in samples of brain damaged patients with hemiparesis. Objective: To determine whether this wide variation might be explained by the different criteria used for diagnosing anosognosia. Methods: 128 acute stroke patients with hemiparesis or hemiplegia were tested for anosognosia for hemiparesis using the anosognosia scale of Bisiach et al . Results: 94% of the patients who were rated as having “mild anosognosia”—that is, they did not acknowledge their hemiparesis spontaneously following a general question about their complaints—suffered from, and mentioned, other neurological deficits such as dysarthria, ptosis, or headache. However, they immediately acknowledged their paresis when they were asked about the strength of their limbs. Their other deficits clearly had a greater impact. These patients had significantly milder paresis than those who denied their disorder even when asked directly about their limbs. Conclusions: Patients who do not mention their paresis spontaneously but do so when questioned about it directly should not be diagnosed having “anosognosia.” If this more conservative cut off criterion is applied to the data of the present as well as previous studies, a frequency of between 10% and 18% for anosognosia for hemiparesis is obtained in unselected samples of acute hemiparetic stroke patients. The incidence thus seems smaller than previously assumed.

Constraint-induced movement therapy: some thoughts about theories and evidence.

Constraint-Induced Movement Therapy (CIMT) is a type of treatment for hemiparetic stroke patients in which the patient is strongly encouraged to use the affected arm. One way of doing this is to immobilise the unaffected arm. This treatment is meant to help patients overcome 'learned non-use'. The learned non-use theory is based on deafferentiation experiments in monkeys. In this review four randomised clinical trials are presented systematically. Although the authors of all four studies reported positive results, the effect sizes calculated without covariates yielded no statistically significant differences. In one of the studies a differential effect was found for patients with sensory disorders and hemineglect, leading to the hypothesis that learned non-use may be primarily related to afferent impairments. It is concluded that the learned non-use theory requires further exploration and that the evidence regarding the effectiveness of CIMT is not yet conclusive.

Abstract 19: Cortical reorganization of hand motor function to primary sensory cortex in hemiparetic patients with a primary motor cortex infarct.

Objective: To demonstrate cortical reorganization in hemiparetic patients with a primary motor cortex (M1) infarct using functional magnetic resonance imaging (fMRI). Design: The hand motor function of 2 hemiparetic stroke patients and 20 control subjects was evaluated by fMRI. Setting: Academic medical center. Participants: 2 hemiparetic patients and 20 control subjects with no history of neurologic disease. Interventions: fMRI was performed using the blood oxygen level-dependent technique at 1.5T. For the motor task paradigm, hand grasp-release movements were performed at a frequency of 1Hz for stimulation, guided with a metronome, over a repeated cycle of 15 seconds of control and 15 seconds of stimulus. Each task paradigm of alternating control-stimulus (30s) was repeated 3 times. Main Outcome Measures: fMRI data were analyzed using SPM-99 software running under the Matlab environment. The images were then smoothed with an 8mm isotropic gaussian kernel. Statistical parametric maps were obtained and voxels were considered significant at P<.001, uncorrected, with the additional requirement of a cluster size of 5 voxels. Results: The contralateral primary sensorimotor cortex was activated by the hand movements of control subjects and of the unaffected side of the 2 patients. Only the contralateral (infarct side) primary sensory cortex (S1) was activated by the affected hand movements of the 2 patients, a result that was not observed in control subjects or the unaffected hand of stroke patients. Conclusions: We believe that the hand motor function of the infarcted M1 of these patients was reorganized into S1. It seems that cortical reorganization took place in patients with an M1 infarct.

Reliability of treadmill exercise testing in older patients with chronic hemiparetic stroke

Dobrovolny CL, Ivey FM, Rogers MA, Sorkin JD, Macko RF. Reliability of treadmill exercise testing in older patients with chronic hemiparetic stroke. Arch Phys Med Rehabil 2003;84:1308–12. Objective To assess the test-retest reliability of cardiopulmonary measurements during peak effort and submaximal treadmill walking tests in older patients with gait-impaired chronic hemiparetic stroke. Design Nonrandomized test-retest. Setting Hospital geriatric research stress testing laboratory. Participants Fifty-three subjects (44 men, 9 women; mean age, 65±8y) with chronic hemiparetic gait after remote (>6mo) ischemic stroke. Patients had mild to moderate chronic hemiparetic gait deficits, making handrail support necessary during treadmill walking. Interventions Peak effort and submaximal effort treadmill walking tests were conducted and then repeated on a separate day at least a week later. Main outcome measures Reliability coefficients ( r) were calculated for heart rate, systolic blood pressure (SBP), oxygen consumption (V o 2 [L/min]), V o 2 (mL·kg −1·min −1), respiratory exchange ratio (RER), rate-pressure product (RPP), and oxygen pulse during peak effort testing. The reliability coefficients for all but SBP and RPP data were calculated from the submaximal tests. Results Heart rate ( r=.87), V o 2peak (L/min) ( r=.92), V o 2peak (mL·kg −1·min −1) ( r=.92), and oxygen pulse ( r=93) were highly reliable parameters during maximal testing in this population. Submaximal testing produced highly reliable results for V̇ o 2 (L/min) ( r=.89) and oxygen pulse ( r=.85). All cardiopulmonary measures except RER had a reliability coefficient greater than .80 during submaximal testing in this population. Conclusion Our study provides the first evidence that peak effort treadmill testing provides highly reliable oxygen consumption measures in chronic hemiparetic stroke patients using minimal handrail support. The submaximal tests were at or near the threshold level of reliability for the 2 most important measures of V̇ o 2 (L/min) and V̇ o 2 (mL·kg −1·min −1) ( r=.89, r=.84, respectively), with the remaining measures falling above .70.

Motor-evoked potentials are facilitated during perceptual identification of hand position in healthy subjects and stroke patients.

To delineate the facilitatory and/or inhibitory influence of relevant and irrelevant sensory afferent information to the motor cortex. The study is based on the assumption that sensorimotor coupling is crucial for motor learning and recovery. The interaction of a standard transcranial magnetic stimulus (TMS) with the facilitatory and/or inhibitory influence that proprioceptive afferent information exerts on the motor cortex was investigated. A neurological rehabilitation hospital. Sixteen healthy subjects and 14 stroke patients. Amplitudes and latencies of motor-evoked potentials (MEPs) recorded from the extensor carpi radialis muscle. The influence of a sensory discrimination task was compared with the influence of a sensory input irrelevant for the task and to a verbal memory task. Recordings were taken after the hand had been moved passively in one of four different positions. In the first trial, TMS was applied without any demand on the subjects. In the second trial, subjects were asked to identify the respective hand position and in the third trial a noun presented at a respective hand position had to be memorized and reproduced after TMS. The sensory discrimination task exerted by far the most prominent facilitatory effect on MEP amplitudes and latencies. An unspecific, albeit reproducible influence on MEP amplitudes was observed when a noun presented at a respective hand position had to be remembered. Using a neurophysiological approach the study demonstrates that a sensory discrimination task based on relevant afferent information to motor centres of the brain forms a prominent facilitatory intervention for those muscle groups that are involved in the task. This holds true for healthy subjects and for hemiparetic stroke patients.

HOME-BASED EXERCISE TRAINING IMPROVES WALKING ENDURANCE IN CHRONIC STROKE PATIENTS

PURPOSE This pilot study evaluated the effectiveness of two approaches of home-based exercise for improving walking endurance, gait velocity and physical fitness in chronic stroke patients. METHODS Nine chronic hemiparetic stroke patients (57 ± 11 y; 46 ± 16 d post-stroke) were randomly allocated to either AEROBIC (n=5) or STRENGTH (n=4) training, each comprising 30 exercise sessions conducted in their homes over an 8–10 week period. AEROBIC involved 30-min of isokinetic cycling at 50% VO2peak (during the initial 4 weeks) progressing to 70–75% VO2peak. Task-related STRENGTH training comprised 3-sets of 10–40 repetitions of box-stepping onto blocks of 5–30 cm height. Walking endurance was assessed, using a 6-min walk test, during a non-intervention baseline period, before training (PRE) and within 2 weeks (POST) of completion. Gait velocity, peak cardiorespiratory fitness, isometric leg muscle strength (1 RM knee-extension on impaired and non-impaired legs) and stepping ability were assessed PRE and POST training. RESULTS Exercise training increased 6-min walk distance at POST by 30.1m in all subjects, and in each group separately. However, only AEROBIC significantly increased their 6-min distance at POST (by 12%). Following exercise training, the average self-selected gait velocity increased from 0.79 to 0.93 m•s−1. Changes in peak cardiorespiratory fitness were significantly greater for AEROBIC (20% improvement) compared to STRENGTH (1% change), whereas maximal isometric leg strength was only significantly greater for STRENGTH subjects (12% increase). CONCLUSION Exercise training proved effective for increasing the capacity for community ambulation in chronic hemiparetic stroke patients by significantly increasing both walking endurance and gait velocity, and by reducing impairments in physical fitness. The results of this study suggest isokinetic aerobic cycle training was a more effective approach than task-related strength training for improving walking endurance in chronic stroke patients.

Physical impairments related to kinetic energy during sit-to-stand and curb-climbing following stroke

Objective. Compare kinetic energy and duration of task during sit-to-stand and curb-climbing of two groups: hemiparetic stroke patients and matched controls. For patients, describe relationships between selected physical impairments and sit-to-stand and curb-climbing performance. Design. Descriptive and correlational. Background. Measures and treatments are best selected after specific limitations in functional activities (e.g., sit-to-stand) and related impairments are identified. Method. Fifteen patients, 29–77 (mean = 53.7) years with recent stroke and 15 demographically matched healthy controls participated. Physical performance variables measured were standing balance, maximum paretic extremity weight-bearing, and knee extension strength. Sit-to-stand and curb-climbing performance were characterized using kinetic energy and task duration. Differences in physical and functional performance between groups were determined. Spearman correlations were calculated between patients’ physical impairments and sit-to-stand and curb-climbing performance. Results. Compared to controls, patients demonstrated reduced kinetic energy ( P⩽0.003) and prolonged duration ( P⩽0.001) for sit-to-stand and curb-climbing. Significant relationships ( r s=0.49–0.50) were demonstrated between sit-to-stand kinetic energy and knee extension strength, standing balance, and maximum weight-bearing. For curb climbing, significant relationships ( r s=0.45) were found between kinetic energy and standing balance and maximum weight-bearing. Conclusion. Impaired balance and maximum weight-bearing are relevant to sit-to-stand and curb-climbing limitations after stroke. Relevance Clinicians treating sit-to-stand or curb-climbing limitations have reason to measure and treat impairments in maximum weight-bearing, knee extension strength, and standing balance.

Hand orientation for grasping and arm joint rotation patterns in healthy subjects and hemiparetic stroke patients

We previously demonstrated that the hand orientation for grasping (azimuth) is strongly coupled to arm movement direction in the horizontal plane. The question is whether this coupling is directly controlled or secondary to a regulation of the arm angular configuration. To this purpose, we quantified hand orientation and arm joint rotations during unconstrained reaching movements in healthy subjects and in patients with hemiparesis due to stroke since they use altered joint rotation patterns for reaching. Seven healthy subjects and eight patients with a right hemiparesis participated (four had a moderate and four had a mild disorder). Four electromagnetic sensors were used to measure hand orientation and to compute the wrist, elbow and shoulder joint angles. Hand azimuth at the time of grasping was correlated to arm movement direction in all the healthy and hemiparetic individuals. In healthy subjects, a regression analysis of the arm joint rotations suggested that the coupling between hand azimuth and movement direction was not due to a correlation with a particular degree of freedom. Patients used different hand orientations for grasping and different joint rotation patterns that varied according to their level of disability and the use of compensatory strategies. The findings observed in both healthy subjects and patients with stroke show that the coupling of hand azimuth for grasping to movement direction was controlled independently of the set of joint rotations used for reaching. This suggests that it is a basic synergy directly controlled by the motor system.

Cortical reorganization associated with motor recovery in hemiparetic stroke patients

We investigated the cortical activation changes associated with motor recovery in eight hemiparetic patients with cerebral infarct by using functional MRI (fMRI), which was performed at 1.5T in parallel with finger flexion-extension movements at a fixed rate. The first fMRI was performed when the patient was able to flex and extend fingers of the affected hand against gravity, and the second fMRI was done when the motor function of the affected hand showed definite improvement. The main cortical activation changes that occurred with motor recovery were an increment in the affected and a decrement in the unaffected primary sensorimotor cortex (SMC) activities. In conclusion, it seems that cortical reorganization occurred in parallel with motor recovery in hemiparetic patients with cerebral infarct.

Cortical reorganization induced by task-oriented training in chronic hemiplegic stroke patients.

We investigated the effect of task-oriented training (TT) on the cortical activation pattern in four chronic hemiparetic stroke patients. A TT program, consisting of six tasks, which were designed to improve hemiparetic upper extremity function, was performed for 40 min/day, 4 days/week for 4 weeks. The functional status of the affected hand and fMRI were assessed before and after the TT program. fMRI was performed at 1.5 T in parallel with timed finger flexion-extension exercises at a fixed rate. The main cortical activation changes with functional recovery were a decrease in the unaffected and an increase in the affected primary sensorimotor cortex activities. In conclusion, it seems that cortical reorganization was induced by the TT program in chronic hemiparetic stroke patients.

Hemiparetic muscle atrophy and increased intramuscular fat in stroke patients

Ryan AS, Dobrovolny CL, Smith GV, Silver KH, Macko RF. Hemiparetic muscle atrophy and increased intramuscular fat in stroke patients. Arch Phys Med Rehabil 2002;83:1703-7. Objective: To determine if skeletal muscle atrophy and greater fat deposition within the muscle are present in the hemiparetic limb of chronic (>6mo) hemiparetic stroke patients. Design: Cross-sectional study. Setting: Hospital-based research center. Participants: Sixty patients (47 men, 13 women; mean age ± standard deviation, 65±9y). Interventions: Not applicable. Main Outcome Measures: Patients underwent a total body scan by dual-energy x-ray absorptiometry to determine percentage of body fat, total lean mass, fat mass, and lean mass of the paretic and nonaffected legs, thighs, and arms. Thirty patients received computed tomography (CT) scans of their midthigh to determine muscle area, subcutaneous fat, and low-density lean tissue, as a measure of fat within the muscle area, of the paretic and nonaffected midthigh. Results: Patients were deconditioned (VO2peak: 1.2±0.3L/min) with a percentage of body fat of 31.4%±9.8% and total lean mass of 51.4±9.1 kg. Lean mass of the paretic leg and thigh were 4% and 3% lower than the nonaffected leg (P<.001), but leg fat was not different. Arm lean mass of the paretic side was 7% lower than the nonaffected side, whereas arm fat was not different. CT studies showed that midthigh muscle area was 20% lower in the paretic limb than in the nonaffected leg (P<.001), midthigh subcutaneous fat was similar, and midthigh low-density lean tissue showed a trend to be 3% higher in the paretic leg (P=.06). The ratio of midthigh low-density lean tissue to muscle area was higher in the paretic leg (P<.001), which indicates a greater intramuscular fat relative to muscle area in the affected limb. Conclusions: Our results show hemiparetic skeletal muscle atrophy and more fat within the muscle, factors that may contribute to functional disability and increased cardiovascular disease risk in chronic hemiparetic stroke patients. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation