Elbow Extension Predicts Motor Impairment and Performance after Stroke

Background and Purpose. Kinematic motion analysis has helped to characterize poststroke reaching strategies with the hemiparetic arm. However, the relationships between reaching strategy and performance on common functional outcome measures remain unclear. Methods. Thirty-five participants were tested for motor performance and motor impairment using the Wolf Motor Function Test (time and functional ability measure) and Fugl-Meyer assessment, respectively. Kinematic motion analysis of a forward reaching paradigm provided potential predictors of reaching strategy including shoulder flexion, elbow extension, and trunk displacement. A stepwise linear regression model with three potential predictors was used in addition to Pearson-product moment correlations. Results. Kinematic analysis of elbow extension predicted performance on both the Wolf Motor Function Test and Fugl-Meyer assessment. Shoulder flexion and trunk displacement did not significantly predict functional or reaching time outcomes. The Wolf Motor Function Test and the Fugl-Meyer assessment were highly correlated. Conclusions. The ability to incorporate elbow extension during reach is a significant predictor of motor performance and hemiparetic arm motor capacity after stroke

A Clinically Relevant Method of Analyzing Continuous Change in Robotic Upper Extremity Chronic Stroke Rehabilitation

Background. Robots designed for rehabilitation of the upper extremity after stroke facilitate high rates of repetition during practice of movements and record precise kinematic data, providing a method to investigate motor recovery profiles over time. Objective. To determine how motor recovery profiles during robotic interventions provide insight into improving clinical gains. Methods. A convenience sample (n = 22), from a larger randomized control trial, was taken of chronic stroke participants completing 12 sessions of arm therapy. One group received 60 minutes of robotic therapy (Robot only) and the other group received 45 minutes on the robot plus 15 minutes of translation-to-task practice (Robot + TTT). Movement time was assessed using the robot without powered assistance. Analyses (ANOVA, random coefficient modeling [RCM] with 2-term exponential function) were completed to investigate changes across the intervention, between sessions, and within a session. Results. Significant improvement (P < .05) in movement time across the intervention (pre vs post) was similar between the groups but there were group differences for changes between and within sessions (P < .05). The 2-term exponential function revealed a fast and slow component of learning that described performance across consecutive blocks. The RCM identified individuals who were above or below the marginal model. Conclusions. The expanded analyses indicated that changes across time can occur in different ways but achieve similar goals and may be influenced by individual factors such as initial movement time. These findings will guide decisions regarding treatment planning based on rates of motor relearning during upper extremity stroke robotic interventions

Role of reaching and non-invasive brain stimulation for applications in stroke rehabilitation, The

2012 Spring.Includes bibliographical references.Upper extremity motor impairments resulting from the neural damage caused by a stroke are often the focus of rehabilitation efforts. Research has demonstrated the plastic potential of the brain to change and reorganize following neurologic injury leading to conceptual shifts in stroke rehabilitation. These shifts include implementing structured, intensive protocols that are based on neurophysiologic, motor control, and motor learning principles to promote use-dependent plasticity. The following investigation is in response to the call from several prominent reviews for research to address specific mechanism based questions to advance stroke rehabilitation. Experiments were conducted to address two aims: the first aim was to determine how reaching task structure influences motor control strategies in survivors of stroke; and the second aim was to determine the effects of non-invasive motor cortex stimulation triggered by voluntary muscle activation to promote use dependent plasticity. Collectively, these studies provide a comprehensive investigation of how certain characteristics of interventions (e.g., the structure of the task) can influence motor control and neurophysiological outcomes in survivors of stroke. The first aim was accomplished with kinematic motion analysis methods to determine how reaching movement patterns were generated by survivors of stroke, and if differences occurred when reaching discretely versus cyclically. The majority of the survivors of stroke in this study were able to maintain continuous, cyclic motion without dwelling periods between movements. The results demonstrated that survivors of stroke utilize a distinct movement pattern during cyclic reaching compared to when performing discrete reaching, i.e., significantly more trunk rotation. We further determined that muscle activation patterns were generally less in the stroke-affected side for muscles in the shoulder girdle (e.g., anterior and posterior deltoid). These results suggest that the incorporation of cyclic reaching tasks may be an important aspect of interventions and assessments because it requires the continuous integration of afferent feedback with the efferent (motor) output to sustain goal-directed reaching. The second aim was to investigate the impact of a novel motor cortex stimulation paradigm, termed functional-rTMS, on motor control and neurophysiologic measures. During functional-rTMS, subjects were required to actively trigger each train of stimulation by sufficiently generating muscle activity in a lateral pinch task. We found that subjects responded differently to functional-rTMS compared to passive-rTMS, i.e., stimulation delivered while subjects were relaxed. Following functional-rTMS, subjects had less inhibition and more facilitation of neural networks in the primary motor cortex. We also observed a differential effect of functional-rTMS on muscle representations such that the agonist was preferentially modulated. The results of this study provide initial support for the potential to use functional-rTMS to modulate specific muscle groups within the same representation for survivors of stroke who often experience imbalances in flexion and extension in the upper extremity. Taken together, this collection of studies informs clinical researchers of a number of important mechanisms that can be incorporated into upper extremity stroke rehabilitation. Subjects who would likely qualify for intensive interventions are able to generate cyclic reaching without detrimental effects on motor performance. Incorporating such tasks within clinical interventions provides a learning opportunity to incorporate afferent feedback with efferent/motor output while completing repetitions. Secondly, functional-rTMS should be further explored with specific attention to the potential benefits of the differential effects on agonist versus antagonist muscle groups

Prioritizing cultural competence in the implementation of an evidence-based practice model

Inherent in implementing an evidence-based practice model are challenges related to maintaining the integrity of the model while ensuring cultural responsiveness. Certainly cultural appropriateness is recognized as critical in the selection and use of evidence-based models, however due to external pressures, many agencies are implementing evidence-based practices without careful consideration of cultural and community nuances. This paper provides an overview of the approach taken by an evaluation team and partner agency in modifying an evidence-based practice model to create congruence with culture of the consumer. The setting for this study was a large, primarily African American, urban area.

A Tablet-Based Tool for Accurate Measurement of Hand Proprioception After Stroke

Background and Purpose: Proprioceptive deficits in the hand are common following stroke, but current clinical measurement techniques are too imprecise to detect subtle impairments or small changes. We developed a tablet-based tool to measure static hand proprioception using an adaptive staircase procedure. Methods: In 16 individuals with chronic stroke and age-matched controls, we quantified proprioception at the metacarpophalangeal joint of the index finger using 3 methods: the tablet task, a custom passive movement direction discrimination test (PMDD), and a manual assessment similar to the Fugl-Meyer (F-M) proprioception subsection. Results: The tablet-based measure and the PMDD both identified impaired proprioception in the affected hand relative to the unaffected hand (P = 0.024 and 0.028), and relative to the control group (P = 0.040 and 0.032), while manual assessment did not. The PMDD had a ceiling effect as movement excursions greater than 15^ were not biomechanically feasible. The tablet-based measure and the PMDD detected impaired proprioception in 56% to 75%, and the F-M in only 29%, of patients. PMDD and tablet-based measures were both correlated with primary tactile sensation, but not manual dexterity. Discussion and Conclusions: Both the tablet-based tool and the custom PMDD performed better than manual assessment. The PMDD may be useful when the deficit is mild or assessment of dynamic proprioception is desired. As the tablet-based measure does not have the ceiling effect that is associated with the PMDD, it may be useful with any level of proprioceptive impairment, and may be preferable if testing or clinician training time needs to be minimized, or pain or spasticity is present

Effects of Motor Cortical Stimulation during Planar Reaching Movement

Background: The purpose was to examine the effects of single pulse transcranial magnetic stimulation (TMS) over primary motor cortex delivered at different times during a center-out reaching task in a robot reaching environment. Methods: Eleven right-handed subjects participated. Movement hotspots and thresholds were determined for each subject, and the stimulation intensity was set at 120% of the movement threshold. TMS was delivered at rest and when subjects performed a series of reaching tasks. The 5 different conditions were: no stimulation, sham stimulation, and stimulation at 150, 500, or 1000 ms post go cue. Outcome measures included TMS-evoked movement during rest and in the 150ms condition, trajectory deviations (no stimulation, sham, and 150ms conditions), and peak velocity (PV), path length, reaction time, acceleration time, and deceleration time for all conditions. Results: When TMS was applied at 150 ms, the evoked path lengths were significantly shorter than at rest and had less deviation than the no-stimulation condition (p &lt; 0.05). Peak velocities were lowest during the no-stimulation condition and highest during the 500ms condition (p &lt; 0.05). Path lengths were significantly shorter during the no-stimulation, sham, and 150ms condition compared to the 500ms and 1000ms conditions. Conclusions: TMS applied during the reaction time phase suppressed movements evoked by TMS, decreased trajectory deviations, and shortened path length, while TMS delivered after movement onset increased PV and path length. TMS stimulation may be delivered to enhance movement parameters and potentially facilitate reach training in the robotic rehabilitation environment