Sandy McCombe Waller

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.

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.

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.

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.

Temporal coordination of the arms during bilateral simultaneous and sequential movements in patients with chronic hemiparesis

Upper extremity (UE) hemiparesis results in decreased movement speed and impaired coordination leading to functional limitations and disability. The effects of UE hemiparesis on bilateral functional reaching have not been studied even though most activities of daily living are bilateral tasks. We examined the characteristics of bilateral simultaneous (SIM-B) and bilateral sequential paretic-lead (SEQ-P) and nonparetic-lead (SEQ-NP) functional reaching tasks at preferred and fast speeds. Sixteen patients with chronic hemiparesis completed three bilateral reaching tasks as fast as possible. A subset of eight participants attempted to complete the tasks at both preferred and fastest possible speeds. Paretic (P) and nonparetic (NP) arms were not different from each other in movement time (MT) or peak velocity in the SIM-B condition. MT and peak velocity differed between the two arms during both SEQ tasks. P MT was shorter and NP MT longer in the SIM-B task compared to SEQ-P and SEQ-NP. The P arm MT was the shortest when moving with the NP arm in a simultaneous task compared to both P and NP lead sequential movements. Despite hemiparesis, the two arms demonstrate a temporal coupling when moving simultaneously. When attempting to move at fastest speed, P arm MT time is better when reaching before or with the NP arm than when reaching after the NP arm showing coupling to the NP limb and increased speed of movement. These coupling effects support the rationale for bilateral arm training for individuals with UE hemiparesis.

Intracortical inhibition and facilitation with unilateral dominant, unilateral nondominant and bilateral movement tasks in left- and right-handed adults

PURPOSE To investigate intracortical inhibition and facilitation in response to unilateral dominant, nondominant and bilateral biceps activation and short-term upper extremity training in right- and left-handed adults. METHODS Paired-pulse transcranial magnetic stimulation was used to measure intracortical excitability in motor dominant and nondominant cortices of 26 nondisabled adults. Neural facilitation and inhibition were measured in each hemisphere during unilateral dominant, nondominant and bilateral arm activation and after training in each condition. RESULTS No differences were seen between right- and left-handed subjects. Intracortical facilitation and decreased inhibition were seen in each hemisphere with unilateral activation/training of contralateral muscles and bilateral muscle activation/training. Persistent intracortical inhibition was seen in each hemisphere with ipsilateral muscle activation/training. Inhibition was greater in the nondominant hemisphere during dominant hemisphere activation (dominant arm contraction). CONCLUSION Strongly dominant individuals show no difference in intracortical responses given handedness. Intracortical activity with unilateral and bilateral arm activation and short-term training differs based on hemispheric dominance, with the motor dominant hemisphere exerting a larger inhibitory influence over the nondominant hemisphere. Bilateral activation and training have a disinhibitory effect in both dominant and nondominant hemispheres.

Arm training in standing also improves postural control in participants with chronic stroke

PURPOSE To prove the concept that postural control will improve without specific balance control training during arm training in standing with individuals with chronic stroke. METHODS Nine participants (mean age 64±7) received training involving hand orthotic assisted grasp, reach and release in standing 1 h, 3×s/week for 6 weeks. Training focused on task completion with no explicit instructions provided for postural alignment, weight shift or balance strategy. Testing consisted of quantified measures using NeuroCom™ Balance Master, Berg Balance Scale (BBS) and Activities-specific Balance Confidence Scale (ABC). RESULTS Post training participants demonstrate increased (p<.05) composite stability scores for sensory organization testing (mean 71.55±12.7-75.55±11). Velocity and directional control of COP weight shift improved for all 9 subjects with 6/9 achieving 100% target acquisition. Directional control improved (p<.05) for medial/lateral movements for all speeds and composite score. Anterior/posterior rhythmic weight shifting increased significantly in COP velocity control at moderate and fast velocities and composite score. Increases in mean BBS (p<.01) from 41.33±10.1-46.88±8.03 exceeded the clinically important cutoff for the scale. Balance confidence improved with ABC mean scores 70.22±14.5-79.55±12.86 (p<.05). Seven participants demonstrated changes above the minimally important difference for this scale. CONCLUSIONS Postural control improved following task oriented arm training in standing without explicit postural control goals, instruction or feedback challenging current training paradigms of isolated postural control training with conscious attention directed to center of pressure location and movement.

Posture-related modulations in motor cortical excitability of the proximal and distal arm muscles.

The effect of postural orientation on the motor corticospinal excitability (MCE) of proximal and distal upper extremity (UE) muscles was investigated. In a crossover design, recruitment curves (RCs), short interval cortical inhibition (SICI) and intracortical facilitation (ICF) of resting anterior deltoid (AD) and first dorsal interosseus (FDI) was assessed in two postures: sitting and standing. Six healthy adults without contraindications to transcranial magnetic stimulation (TMS) participated in the study. TMS was applied over the motor cortical representation of FDI and AD at intensities ranging from 90% to 200% of resting motor threshold (RMT) in increments of 10%. SICI and ICF were assessed for each muscle using a conditioning stimulus (80% RMT) preceding a test stimulus (120% RMT) with an interstimulus interval of 2 ms and 15 ms, respectively. For AD, but not FDI, there was a significant and consistent increase in RC slope during standing compared to sitting. For FDI, there was no difference in ICF and SICI between sitting and standing. However, for AD, while there was no difference in ICF between the two postures, there was a clear trend for SICI to decrease (p=0.06) in standing compared to sitting. These results indicate that postural change from sitting to standing, affects the MCE of proximal but not distal muscles. While this indicates the role of proximal UE muscles in postural control, it also implies that rehabilitation protocols for enhancing proximal arm motor function may be advantaged if administered in a standing posture.

Compensatory arm reaching strategies after stroke: Induced position analysis

After stroke, movement patterns of the upper limb (UL) during functional arm reaching change to accommodate altered constraints. These compensatory movement control strategies do not, however, have a one-to-one mapping with posttraining outcomes. In this study, we quantify arm movement control strategies in unilateral and bilateral reaching tasks using induced position analysis. In addition, we assess how those strategies are associated with UL residual impairments and with functional improvement after a specific bilateral arm training intervention. Twelve individuals with chronic stroke were measured while reaching to a box as part of their pre- and posttesting assessments. Other measurements included the Fugl-Meyer Upper Extremity Assessment (FM), Modified Wolf Motor Function Test (WT), and the University of Maryland Arm Questionnaire for Stroke (UMAQS). We identified arm control strategies that did not differ between unilateral and bilateral tasks but did differ by FM impairment level and by predicted gains in WT but not UMAQS. Increased shoulder relative to elbow moment contribution was associated with less impairment and greater gains of speed in functional tasks. These results suggest that one goal of training to achieve better outcomes may be to decrease the abnormal coupling of the shoulder and elbow.

Comparing the effects of adapting to a weight on one leg during treadmill and overground walking: A pilot study

BACKGROUND Locomotor adaptation has been suggested as a way to improve gait symmetry in individuals post-stroke. Most perturbation methods utilize costly, specialized equipment. The use of a unilateral leg weight may provide a low cost, clinically translatable alternative. Furthermore, previous studies have suggested that adaptation context may affect movement outcomes. The purpose of this study was to assess the ability of a unilaterally applied ankle weight to drive locomotor adaptation and determine the effect of context (treadmill versus overground) in young, non-disabled participants. METHODS Eighteen young non-disabled adults were randomly assigned to receive 10min of walking on a treadmill with a weight (TG), overground with a weight (OG) or as a control on a treadmill/overground without a weight (CG). Outcomes measured before, during and after adaptation were: step length symmetry, single limb support symmetry and gait speed. RESULTS After adding the weight, single limb support immediately became asymmetrical for all participants without changes in step length symmetry. After walking for 10min, TG step length became asymmetrical. After weight removal, both TG and OG had increased step length asymmetry. TG decreased single limb support asymmetry while OG did not. After walking overground without the weight, walking parameters eventually returned to baseline in both weighted groups. The control group showed no changes. CONCLUSION A unilaterally applied ankle weight appears able to cause gait adaptation in young, non-disabled participants. However different adaptive changes in the gait pattern are made by the nervous system when the perturbation is applied in different contexts.