Jill Whitall

Repetitive Bilateral Arm Training With Rhythmic Auditory Cueing Improves Motor Function in Chronic Hemiparetic Stroke

Background and Purpose Chronic upper extremity hemiparesis is a leading cause of functional disability after stroke. We investigated the hypothesis that bilateral arm training with rhythmic auditory cueing (BATRAC) will improve motor function in the hemiparetic arm of stroke patients. Methods In this single group pilot study we determined the effects of 6 weeks of BATRAC on 14 patients with chronic hemiparetic stroke (median time after stroke, 30 months) immediately after training and at 2 months after training. Four 5-minute periods per session (3 times per week) of BATRAC were performed with the use of a custom-designed arm training machine. Results The patients showed significant and potentially durable increases in the following: Fugl-Meyer Upper Extremity Motor Performance Test of impairment (P <0.0004), Wolf Motor Function Test (performance time measure, P <0.02), and University of Maryland Arm Questionnaire for Stroke measuring daily use of the hemiparetic arm (P <0.002). Isometric strength improved in elbow flexion (P <0.05) and wrist flexion (P <0.02) for the paretic arm and in elbow flexion (P <0.02) and wrist extension (P <0.02) for the nonparetic arm. Active range of motion improved for paretic-side shoulder extension (P <0.01), wrist flexion (P <0.004), and thumb opposition (P <0.002), and passive range of motion improved for paretic wrist flexion (P <0.03). Conclusions Six weeks of BATRAC improves functional motor performance of the paretic upper extremity as well as a few changes in isometric strength and range of motion. These benefits are largely sustained at 8 weeks after training cessation.

Treadmill Exercise Activates Subcortical Neural Networks and Improves Walking After Stroke A Randomized Controlled Trial

Background and Purpose— Stroke often impairs gait thereby reducing mobility and fitness and promoting chronic disability. Gait is a complex sensorimotor function controlled by integrated cortical, subcortical, and spinal networks. The mechanisms of gait recovery after stroke are not well understood. This study examines the hypothesis that progressive task-repetitive treadmill exercise (T-EX) improves fitness and gait function in subjects with chronic hemiparetic stroke by inducing adaptations in the brain (plasticity). Methods— A randomized controlled trial determined the effects of 6-month T-EX (n=37) versus comparable duration stretching (CON, n=34) on walking, aerobic fitness and in a subset (n=15/17) on brain activation measured by functional MRI. Results— T-EX significantly improved treadmill-walking velocity by 51% and cardiovascular fitness by 18% (11% and −3% for CON, respectively; P<0.05). T-EX but not CON affected brain activation during paretic, but not during nonparetic limb movement, showing 72% increased activation in posterior cerebellar lobe and 18% in midbrain (P<0.005). Exercise-mediated improvements in walking velocity correlated with increased activation in cerebellum and midbrain. Conclusions— T-EX improves walking, fitness and recruits cerebellum-midbrain circuits, likely reflecting neural network plasticity. This neural recruitment is associated with better walking. These findings demonstrate the effectiveness of T-EX rehabilitation in promoting gait recovery of stroke survivors with long-term mobility impairment and provide evidence of neuroplastic mechanisms that could lead to further refinements in these paradigms to improve functional outcomes.

Lesion location alters brain activation in chronically impaired stroke survivors.

Recovery of motor function after stroke is associated with reorganization in central motor networks. Functional imaging has demonstrated recovery-dependent alterations in brain activation patterns when compared to healthy controls. These alterations are variable across stroke subjects. Factors identified as contributing to this variability are the degree of functional impairment, the time interval since stroke, and rehabilitative therapies. Here, the hypothesis is tested that lesion location influences the activation patterns. Using functional magnetic resonance imaging, the objective was to characterize similarities or differences in movement-related activation patterns in patients chronically disabled by cortical plus subcortical or subcortical lesions only. Brain activation was mapped during paretic and non-paretic movement in 11 patients with subcortical stroke, in nine patients with stroke involving sensorimotor cortex, and in eight healthy volunteers. Patient groups had similar average motor deficit as measured by a battery of scores and strength measures. Substantial differences between patients groups were found in activation patterns associated with paretic limb movement: whereas contralateral motor cortex, ipsilateral cerebellum (relative to moving limb), bilateral mesial (cingulate, SMA), and perisylvian regions were active in subcortical stroke, cortical patients recruited only ipsilateral postcentral mesial hemisphere regions, and areas at the rim of the stroke cavity. For both groups, activation in ipsilateral postcentral cortex correlated with motor function; in subcortical stroke, the same was found for mesial and perisylvian regions. Overall, brain activation in cortical stroke was less, while in subcortical patients, more than in healthy controls. For non-paretic movement, activation patterns were similar to control in cortical patients. In subcortical patients, however, activation patterns differed: the activation of non-paretic movement was similar to that of paretic movement (corrected for side). The data demonstrate more differences than similarities in the central control of paretic and non-paretic limb movement in patients chronically disabled by subcortical versus cortical stroke. Whereas standard motor circuitry is utilized in subcortical stroke, alternative networks are recruited after cortical stroke. This finding proposes lesion-specific mechanisms of reorganization. Optimal activation of these distinct networks may require different rehabilitative strategies.

Comparing brain activation associated with isolated upper and lower limb movement across corresponding joints

It was shown recently that functional activation across brain motor areas during locomotion and foot movements are similar but differ substantially from activation related to upper extremity movement (Miyai [ 2001 ]: Neuroimage 14:1186–1192). The activation pattern may be a function of the behavioral context of the movement rather than of its mechanical properties. We compare motor system activation patterns associated with isolated single‐joint movement of corresponding joints in arm and leg carried out in equal frequency and range. Eleven healthy volunteers underwent BOLD‐weighted fMRI while performing repetitive elbow or knee extension/flexion. To relate elbow and knee activation to the well‐described patterns of finger movement, serial finger‐to‐thumb opposition was assessed in addition. After identifying task‐related voxels using statistical parametric mapping, activation was measured in five regions of interest (ROI; primary motor [M1] and somatosensory cortex [S1], premotor cortex, supplementary motor area [SMA] divided into preSMA and SMA‐proper, and cerebellum). Differences in the degree of activation across ROIs were found between elbow and knee movement. SMA‐proper activation was prominent for knee, but almost absent for elbow movement (P < 0.05); finger movement produced small but constant SMA‐proper activation. Ipsilateral M1 activation was detected during knee and finger movement, but was absent for the elbow task (P < 0.05). Knee movement showed less lateralization in M1 and S1 than other tasks (P < 0.05). The data demonstrate that central motor structures contribute differently to isolated elbow and knee movement. Activation during knee movement shows similarities to gait‐related activation patterns. Hum. Brain Mapping 17:131–140, 2002.

Bilateral and Unilateral Arm Training Improve Motor Function Through Differing Neuroplastic Mechanisms A Single-Blinded Randomized Controlled Trial

Background and Purpose. This randomized controlled trial tests the efficacy of bilateral arm training with rhythmic auditory cueing (BATRAC) versus dose-matched therapeutic exercises (DMTEs) on upper-extremity (UE) function in stroke survivors and uses functional magnetic resonance imaging (fMRI) to examine effects on cortical reorganization. Methods. A total of 111 adults with chronic UE paresis were randomized to 6 weeks (3×/week) of BATRAC or DMTE. Primary end points of UE assessments of Fugl-Meyer UE Test (FM) and modified Wolf Motor Function Test Time (WT) were performed 6 weeks prior to and at baseline, after training, and 4 months later. Pretraining and posttraining, fMRI for UE movement was evaluated in 17 BATRAC and 21 DMTE participants. Results. The improvements in UE function (BATRAC: FM Δ = 1.1 + 0.5, P = .03; WT Δ = −2.6 + 0.8, P < .00; DMTE: FM Δ = 1.9 + 0.4, P < .00; WT Δ = −1.6 + 0.7; P = .04) were comparable between groups and retained after 4 months. Satisfaction was higher after BATRAC than DMTE (P = .003). BATRAC led to significantly higher increase in activation in ipsilesional precentral, anterior cingulate and postcentral gyri, and supplementary motor area and contralesional superior frontal gyrus (P < .05). Activation change in the latter was correlated with improvement in the WMFT (P = .01). Conclusions. BATRAC is not superior to DMTE, but both rehabilitation programs durably improve motor function for individuals with chronic UE hemiparesis and with varied deficit severity. Adaptations in brain activation are greater after BATRAC than DMTE, suggesting that given similar benefits to motor function, these therapies operate through different mechanisms.

Brain activation of lower extremity movement in chronically impaired stroke survivors

Lower extremity paresis poses significant disability to chronic stroke survivors. Unlike for the upper extremity, cortical adaptations in networks controlling the paretic leg have not been characterized after stroke. Here, the hypotheses are that brain activation associated with unilateral knee movement in chronic stroke survivors is abnormal, depends on lesion location, and is related to walking ability. Functional magnetic resonance imaging of unilateral knee movement was obtained in 31 patients 26.9 months (mean, IQ range: 11.3-68.1) after stroke and in 10 age-matched healthy controls. Strokes were stratified according to lesion location. Locomotor disability (30 ft walking speed) did not differ between patient groups (9 cortical, 12 subcortical, 10 brainstem lesions). Significant differences in brain activation as measured by voxel counts in 10 regions of interest were found between controls and patients with brainstem (P = 0.006) and cortical strokes (P = 0.002), and between subcortical and cortical patients (P = 0.026). Statistical parametric mapping of data per group revealed similar activation patterns in subcortical patients and controls with recruitment of contralateral primary motor cortex (M1), supplementary motor area (SMA), and bilateral somatosensory area 2 (S2). Cortical recruitment was reduced in brainstem and cortical stroke. Better walking was associated with lesser contralateral sensorimotor cortex activation in brainstem, but stronger recruitment of ipsilateral sensorimotor and bilateral somatosensory cortices in subcortical and cortical patients, respectively. A post hoc comparison of brainstem patients with and without mirror movements (50%) revealed lesser recruitment of ipsilateral cerebellum in the latter. Subcortical patients with mirror movements (58%) showed lesser bilateral sensorimotor cortex activation. No cortical patient had mirror movements. The data reveal adaptations in networks controlling unilateral paretic knee movement in chronic stroke survivors. These adaptations depend on lesion location and seem to have functional relevance for locomotion.

Short-duration robotic therapy in stroke patients with severe upper-limb motor impairment

Chronic motor deficits in the upper limb (UL) are a major contributor to disability following stroke. This study investigated the effect of short-duration robot-assisted therapy on motor impairment, as measured by clinical scales and robot-derived performance measures in patients with chronic, severe UL impairments after stroke. As part of a larger study, 15 individuals with chronic, severe UL paresis (Fugl-Meyer < 15) after stroke (minimum 6 mo postonset) performed 18 sessions of robot-assisted UL rehabilitation that consisted of goal-directed planar reaching tasks over a period of 3 weeks. Outcome measures included the Fugl-Meyer Assessment, the Motor Power Assessment, the Wolf Motor Function Test, the Stroke Impact Scale, and five robot-derived measures that reflect motor control (aiming error, mean speed, peak speed, mean:peak speed ratio, and movement duration). Robot-assisted training produced statistically significant improvements from baseline to posttreatment in the Fugl-Meyer and Motor Power Assessment scores and the quality of motion (quantified by a reduction in aiming error and movement duration with an increase in mean speed and mean:peak speed ratio). Our findings indicate that robot-assisted UL rehabilitation can reduce UL impairment and improve motor control in patients with severe UL paresis from chronic stroke.

Hand dominance and side of stroke affect rehabilitation in chronic stroke

Objective: To examine the difference between upper extremity deficits in subjects with left versus right hemispheric lesions at baseline and after bilateral arm training. Design: A one-way ANOVA was used to detect group differences and a least square means analysis used to determine significance in pre-to-post scores for each group. Setting: Testing was in the Physical Therapy and Rehabilitation Science Department Research Laboratory, University of Maryland, Baltimore. Training was at the Senior Exercise Rehabilitation Center in the Veterans Administration Hospital, Baltimore. Subjects: Twenty-two (11 left hemispheric lesion, 11 right hemispheric lesion) right-handed subjects with chronic stroke. Interventions: A six-week nonprogressive repetitive bilateral arm training with rhythmic auditory cueing (BATRAC). Main measuresy: Fugl-Meyer Upper Extremity Test, Wolf Motor Arm Test, University of Maryland Arm Questionnaire for Stroke (UMAQS), isometric strength and active and passive range of motion for both sides. Results: No statistical differences were seen at baseline between groups in this sample. Both groups demonstrated improvement after BATRAC in Fugl-Meyer Upper Extremity Test (change scores of those with left lesions-5.5; right lesions-3.6) and UMAQS (change scores of those with left lesions-5 and right lesions-2.9). Additionally, patients with left hemispheric lesions but not right lesions made improvements in the Wolf Motor Arm Test (time and weight), in strength measures of paretic elbow flexion, shoulder extension, shoulder abduction and nonparetic wrist flexion, wrist extension and shoulder abduction. Conclusions: There were no baseline motor function differences between those with left and right hemispheric lesions in this sample. There was a clear training response advantage for patients with left hemispheric lesions after completing six weeks of bilateral arm training. As a result, treatment approaches for upper extremity hemiparesis may need to be more specifically selected based on side of stroke.

Robotic upper-limb neurorehabilitation in chronic stroke patients

This pilot study tested the effectiveness of an intense, short-term upper-limb robotic therapy for improvement in motor outcomes among chronic stroke patients. We enrolled 30 subjects with upper-limb deficits due to stroke of at least 6 mo duration and with a Motor Power Assessment grade of 3 or less. Over 3 wk, 18 sessions of robot-assisted task-specific therapy were delivered with the use of a robotic exercise device that simulates a conventional therapy known as skateboard therapy. Primary outcome measures included reliable, validated impairment and disability measures of upper-limb motor function. Statistically significant improvements were observed for severely impaired participants when we compared baseline and posttreatment outcomes (p < 0.05). These results are important because they indicate that improvement is not limited to those with moderate impairments but is possible among severely impaired chronic stroke patients as well. Moderately and severely impaired patients in our study were able to tolerate a massed-practice therapy paradigm with intensive, frequent, and repetitive treatment. This information is useful in determining the optimal target population, intensity, and duration of robotic therapy and sample size for a planned larger trial.

Improved Hemiparetic Muscle Activation in Treadmill versus Overground Walking

Objective. Treadmill training is a promising tool for retraining gait after stroke. The treadmill induces an immediate shift toward symmetry and longer paretic stance times due to altered muscle activation (active) or the motorized belt (passive). The authors investigated vastus lateralis and medial hamstrings activation differences between treadmill and overground walking in participants with stroke. Methods. Vastus lateralis and medial hamstrings surface electromyography was recorded during velocity-matched overground and treadmill walking in 19 chronically hemiparetic subjects. Variables from ensemble averages of electromyography included burst onset and offset times (% cycle), duration (% cycle), integrated amplitude (mV·% cycle), and onset relative to foot strike (% cycle). Conditions were compared using paired t-tests (α = 0.05). Results. Paretic vastus lateralis onset occurred earlier in the treadmill condition (overground: 47.1%, treadmill: 41.9%, P = 0.01). For nonparetic vastus lateralis in the treadmill condition, onset occurred later (overground: 85.2%, treadmill: 87.6%, P = 0.09), offset occurred earlier (overground: 54.7%, treadmill: 47.8%, P = 0.03), duration was shorter (overground: 69.1%, treadmill: 61.2%, P = 0.01), and integrated amplitude was lower (overground: 14.1, treadmill: 10.6, P = 0.05). Within limbs, paretic vastus lateralis onset occurred earlier relative to paretic foot strike. Nonparetic vastus lateralis onset occurred later relative to nonparetic foot strike. Conclusions. Treadmill walking induces immediate changes in vastus lateralis, but not medial ham-strings, activation patterns. These alterations (earlier paretic vastus lateralis onset and later nonparetic vastus lateralis onset) during treadmill versus overground walking parallel the increased symmetry in gait patterning.