Keith R. Lohse

Is More Better? Using Metadata to Explore Dose–Response Relationships in Stroke Rehabilitation

Background and Purpose— Neurophysiological models of rehabilitation and recovery suggest that a large volume of specific practice is required to induce the neuroplastic changes that underlie behavioral recovery. The primary objective of this meta-analysis was to explore the relationship between time scheduled for therapy and improvement in motor therapy for adults after stroke by (1) comparing high doses to low doses and (2) using metaregression to quantify the dose–response relationship further. Methods— Databases were searched to find randomized controlled trials that were not dosage matched for total time scheduled for therapy. Regression models were used to predict improvement during therapy as a function of total time scheduled for therapy and years after stroke. Results— Overall, treatment groups receiving more therapy improved beyond control groups that received less (g=0.35; 95% confidence interval, 0.26–0.45). Furthermore, increased time scheduled for therapy was a significant predictor of increased improvement by itself and when controlling for linear and quadratic effects of time after stroke. Conclusions— There is a positive relationship between the time scheduled for therapy and therapy outcomes. These data suggest that large doses of therapy lead to clinically meaningful improvements, controlling for time after stroke. Currently, trials report time scheduled for therapy as a measure of therapy dose. Preferable measures of dose would be active time in therapy or repetitions of an exercise.

How changing the focus of attention affects performance, kinematics, and electromyography in dart throwing☆

Research has found an advantage for an external focus of attention in motor control and learning; instructing subjects to focus on the effects of their actions, rather than on body movements, can improve performance during training and retention testing. Previous research has mostly concentrated on movement outcomes, not on the quality of the movement itself. Thus, this study combined surface electromyography (EMG) with motion analysis and outcome measures in a dart throwing task, making this the first study that includes a comprehensive analysis of changes in motor performance as a function of attentional focus. An external focus of attention led to better performance (less absolute error), decreased preparation time between throws, and reduced EMG activity in the triceps brachii. There was also some evidence of increased variability for kinematic measures of the shoulder joint under an external focus relative to an internal focus. These results suggest improved movement economy with an external focus of attention.

Virtual Reality Therapy for Adults Post-Stroke: A Systematic Review and Meta-Analysis Exploring Virtual Environments and Commercial Games in Therapy

Background The objective of this analysis was to systematically review the evidence for virtual reality (VR) therapy in an adult post-stroke population in both custom built virtual environments (VE) and commercially available gaming systems (CG). Methods MEDLINE, CINAHL, EMBASE, ERIC, PSYCInfo, DARE, PEDro, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews were systematically searched from the earliest available date until April 4, 2013. Controlled trials that compared VR to conventional therapy were included. Population criteria included adults (>18) post-stroke, excluding children, cerebral palsy, and other neurological disorders. Included studies were reported in English. Quality of studies was assessed with the Physiotherapy Evidence Database Scale (PEDro). Results Twenty-six studies met the inclusion criteria. For body function outcomes, there was a significant benefit of VR therapy compared to conventional therapy controls, G = 0.48, 95% CI = [0.27, 0.70], and no significant difference between VE and CG interventions (P = 0.38). For activity outcomes, there was a significant benefit of VR therapy, G = 0.58, 95% CI = [0.32, 0.85], and no significant difference between VE and CG interventions (P = 0.66). For participation outcomes, the overall effect size was G = 0.56, 95% CI = [0.02, 1.10]. All participation outcomes came from VE studies. Discussion VR rehabilitation moderately improves outcomes compared to conventional therapy in adults post-stroke. Current CG interventions have been too few and too small to assess potential benefits of CG. Future research in this area should aim to clearly define conventional therapy, report on participation measures, consider motivational components of therapy, and investigate commercially available systems in larger RCTs. Trial Registration Prospero CRD42013004338

Video games and rehabilitation: using design principles to enhance engagement in physical therapy.

Patient nonadherence with therapy is a major barrier to rehabilitation. Recovery is often limited and requires prolonged, intensive rehabilitation that is time-consuming, expensive, and difficult. We review evidence for the potential use of video games in rehabilitation with respect to the behavioral, physiological, and motivational effects of gameplay. In this Special Interest article, we offer a method to evaluate effects of video game play on motor learning and their potential to increase patient engagement with therapy, particularly commercial games that can be interfaced with adapted control systems. We take the novel approach of integrating research across game design, motor learning, neurophysiology changes, and rehabilitation science to provide criteria by which therapists can assist patients in choosing games appropriate for rehabilitation. Research suggests that video games are beneficial for cognitive and motor skill learning in both rehabilitation science and experimental studies with healthy subjects. Physiological data suggest that gameplay can induce neuroplastic reorganization that leads to long-term retention and transfer of skill; however, more clinical research in this area is needed. There is interdisciplinary evidence suggesting that key factors in game design, including choice, reward, and goals, lead to increased motivation and engagement. We maintain that video game play could be an effective supplement to traditional therapy. Motion controllers can be used to practice rehabilitation-relevant movements, and well-designed game mechanics can augment patient engagement and motivation in rehabilitation. We recommend future research and development exploring rehabilitation-relevant motions to control games and increase time in therapy through gameplay. Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A61) for more insights from the authors.

Neuromuscular effects of shifting the focus of attention in a simple force production task.

ABSTRACT Research on the focus of attention has begun exploring the physiological changes that underlie the difference between internal and external foci of attention. However, previous electromyography studies have used dynamic tasks, making it difficult to interpret electrophysiological data. The authors analyzed how the focus of attention affects a subjects ability to perform an isometric force production task (focus was directed either at the force platform or the muscles responsible for force production). Subjects received practice without attentional focus instructions and then completed blocks of trials with an external and internal attentional focus separately. An external focus led to significantly less error overall and reduced surface electromyography activity with lower median power frequencies in the antagonist muscle, but attentional focus had no effects on the agonist muscle. Thus, an external focus of attention led to more efficient motor unit recruitment patterns (reduced cocontraction) and improved performance. Posttest surveys revealed subjects were aware of their improved performance with an external focus.

Dose and timing in neurorehabilitation: Prescribing motor therapy after stroke

PURPOSE OF REVIEW Prescribing the most appropriate dose of motor therapy for individual patients is a challenge because minimal data are available and a large number of factors are unknown. This review explores the concept of dose and reviews the most recent findings in the field of neurorehabilitation, with a focus on relearning motor skills after stroke. RECENT FINDINGS Appropriate dosing involves the prescription of a specific amount of an active ingredient, at a specific frequency and duration. Dosing parameters, particularly amount, are not well defined or quantified in most studies. Compiling data across studies indicates a positive, moderate dose-response relationship, indicating that more movement practice results in better outcomes. This relationship is confounded by time after stroke, however, wherein longer durations of scheduled therapy may not be beneficial in the first few hours, days, and/or weeks. SUMMARY These findings suggest that substantially more movement practice may be necessary to achieve better outcomes for people living with the disabling consequences of stroke. Preclinical investigations are needed to elucidate many of the unknowns and allow for a more biologically driven rehabilitation prescription process. Likewise, clinical investigations are needed to determine the dose-response relationships and examine the potential dose-timing interaction in humans.

The role of attention in motor control

Research on the focus of attention (FOA) in motor control has found a consistent advantage for focusing externally (on the effects of ones actions) compared to focusing internally (on ones body mechanics). However, most of this work has concentrated on movement outcomes, leaving open the question of how external attention changes the movement itself. Somewhat paradoxically, recent research has found that external attention also increases trial-by-trial movement variability. To explain these findings, we propose a theory of attention in motor control, grounded in optimal control theory, wherein variability is minimized along attended aspects of the movement. Internal attention thus reduces variability in individual bodily dimensions (positions and velocities of effectors), whereas external attention minimizes variability in the task outcome. Because the goal of a task defines a dimension in the movement space that is generally oblique to bodily dimensions, external attention should increase correlations among bodily dimensions while allowing their individual variances to grow. The current experiment tests these predictions in a dart-throwing task. External FOA led to more accurate performance and increased variability in the motion of the throwing arm, concomitant with stronger correlations among bodily dimensions (shoulder, elbow, and wrist positions and velocities) in a manner consistent with the task kinematics. These findings indicate a shift in the control policy of the motor system, consistent with the proposed theory. These results suggest an important role of attention as a control parameter in the regulation of the motor system, and more broadly illustrate the importance of cognitive mechanisms in motor behavior.

Defining the Focus of Attention: Effects of Attention on Perceived Exertion and Fatigue

This manuscript presents two experiments designed to explore the effects of attention on perceived exertion and time to failure in a fatiguing athletic task. There were two major motivating factors for these experiments. First, there are few studies evaluating attentional focus effects in endurance tasks and, second, there is a lack of integration between studies of attentional focus as external/internal (e.g., Wulf, 2007a) compared to associative/dissociative (e.g., Stevinson and Biddle, 1998). In Experiment 1, we used a fatiguing wall-sit posture (essentially a complex, isometric task) to compare two different types of external attention with an internal focus on the position of the legs. An external focus (regardless of type) increased the time taken to failure and reduced perceived exertion. In Experiment 2, we manipulated subjects’ expectancy of fatigue to test the interaction of attention and expectancy (both top-down factors) in this highly fatiguing task. Previous theories of attention during endurance tasks have suggested that as fatigue/pain increase, bottom-up factors begin to dominate subjects’ attention. While this may be true, Experiment 2 showed that even in a highly fatiguing task, attentional strategies, and expectancies affected the time to failure and perceived exertion.

Motor skill acquisition across short and long time scales: a meta-analysis of neuroimaging data.

In this systematic review and meta-analysis, we explore how the time scale of practice affects patterns of brain activity associated with motor skill acquisition. Fifty-eight studies that involved skill learning with healthy participants (117 contrasts) met inclusion criteria. Two meta-contrasts were coded: decreases: peak coordinates that showed decreases in brain activity over time; increases: peak coordinates that showed increases in activity over time. Studies were grouped by practice time scale: short (≤1 h; 25 studies), medium (>1 and ≤24 h; 18 studies), and long (>24h to 5 weeks; 17 studies). Coordinates were analyzed using Activation Likelihood Estimation to show brain areas that were consistently activated for each contrast. Across time scales, consistent decreases in activity were shown in prefrontal and premotor cortex, the inferior parietal lobules, and the cerebellar cortex. Across the short and medium time scales there were consistent increases in supplementary and primary motor cortex and dentate nucleus. At the long time scale, increases were seen in posterior cingulate gyrus, primary motor cortex, putamen, and globus pallidus. Comparisons between time scales showed that increased activity in M1 at medium time scales was more spatially consistent across studies than increased activity in M1 at long time scales. Further, activity in the striatum (viz. putamen and globus pallidus) was consistently more rostral in the medium time scale and consistently more caudal in the long time scale. These data support neurophysiological models that posit that both a cortico-cerebellar system and a cortico-striatal system are active, but at different time points, during motor learning, and suggest there are associative/premotor and sensorimotor networks active within each system.

The influence of attention on learning and performance: pre-movement time and accuracy in an isometric force production task.

Lohse, Sherwood, and Healy (2010) found that an external focus of attention (FOA) improved performance in a dart-throwing task and reduced the time taken between throws, but using the time between trials as a measure of preparation time is relatively crude. Thus, the current experiment analyzed how FOA affects accuracy and pre-movement time in an isometric force production task, to study how FOA affected motor planning. In the current experiment, training with an external focus improved the accuracy of the isometric force production task during training and during retention and transfer testing. During training, an external FOA also significantly reduced pre-movement time in early trials. These findings are interpreted as reduced explicit control of movement as a function of an external FOA, and help to integrate FOA research with other motor control phenomena and neuropsychological theories of motor control.