Premotor and Posterior Parietal Cortex Activity is Increased for Slow, as well as Fast Walking Poststroke: An fNIRS Study.

Methods: Twenty individuals in the chronic stage of stroke walked: (1) at their normal pace, (2) slower than normal, and (3) as fast as possible. Functional near-infrared spectroscopy was used to assess bilateral prefrontal, premotor, sensorimotor, and posterior parietal cortices during walking. Results: No significant differences in laterality were observed between walking speeds. The ipsilesional prefrontal cortex was overall more active than the contralesional prefrontal cortex. Premotor and posterior parietal cortex activity were larger during slow and fast walking compared to normal-paced walking with no differences between slow and fast walking. Greater increases in brain activation in the ipsilesional prefrontal cortex during fast compared to normal-paced walking related to greater gait speed modulation. Conclusions: Brain activation is not linearly related to gait speed. Ipsilesional prefrontal cortex, bilateral premotor, and bilateral posterior parietal cortices are important areas for gait speed modulation and could be an area of interest for neurostimulation.

Evaluating the Dissemination and Implementation Impact of a Rehabilitation Intervention: The Graded Repetitive Arm Supplementary Program (GRASP).

Purpose: To evaluate the dissemination and implementation impacts of a rehabilitation intervention. Methods: Systematic evaluation of data sources including academic publishing metrics, publications, and surveys was used to describe the dissemination and implementation impact of the graded repetitive arm supplementary program (GRASP). Three categories in the Payback Framework were evaluated: knowledge production and dissemination, benefits to future research and research use, and real-world uptake and implementation. Results: In the Knowledge production and dissemination category, seven publications, authored by the GRASP research team, were associated with the GRASP, and there were approximately 17,000 download counts of GRASP manuals from the website from 120 countries. In the Benefits to future research and research use category, 15 studies and 8 registered clinical trials, authored by researchers outside of the GRASP team, have used GRASP as an intervention. In the real-world uptake and implementation category, GRASP has informed recommendations in 2 clinical guidelines and 20 review papers, and had high implementation uptake (e.g., 35% [53/154] of UK therapists surveyed had used GRASP; 95% [649/681] who downloaded GRASP had used it). More than 75% of those who had used GRASP identified that GRASP provides more intensity in upper extremity rehabilitation, is evidence-based and easy to implement, and the equipment and manual are easy to obtain. Conclusion: The Payback Framework is useful to evaluate the dissemination and implementation impacts of a rehabilitation intervention. GRASP has been implemented extensively in clinical practice and community in a relatively short time since it has been developed.

Perspectives of users for a future interactive wearable system for upper extremity rehabilitation following stroke: a qualitative study.

BACKGROUND: Wearable sensor technology can facilitate diagnostics and monitoring of people with upper extremity (UE) paresis after stroke. The purpose of this study is to investigate the perspectives of clinicians, people living with stroke, and their caregivers on an interactive wearable system that detects UE movements and provides feedback. METHODS: This qualitative study used semi-structured interviews relating to the perspectives of a future interactive wearable system including a wearable sensor to capture UE movement and a user interface to provide feedback as the means of data collection. Ten rehabilitation therapists, 9 people with stroke, and 2 caregivers participated in this study. RESULTS: Four themes were identified (1) "Everyone is different" highlighted the need for addressing individual user's rehabilitation goal and personal preference; (2) "The wearable system should identify UE and trunk movements" emphasized that in addition to arm, hand, and finger movements, detecting compensatory trunk movements during UE movements is also of interest; (3) "Both quality and amount of movements are necessary to measure" described the parameters related to how well and how much the user is using their affected UE that participants envisioned the system to monitor; (4) "Functional activities should be practiced by the users" outlined UE movements and activities that are of priority in designing the system. CONCLUSIONS: Narratives from clinicians, people with stroke, and their caregivers offer insight into the design of interactive wearable systems. Future studies examining the experience and acceptability of existing wearable systems from end-users are warranted to guide the adoption of this technology.

A Pilot Study for Remote Evaluation of Upper Extremity Motor Function After Stroke: The Arm Capacity and Movement Test (ArmCAM).

IMPORTANCE: A simple measure that can be administered remotely by means of videoconferencing is needed for telerehabilitation. OBJECTIVE: To develop a valid and reliable measure, the Arm Capacity and Movement Test (ArmCAM), that can be administered remotely by means of videoconferencing to evaluate upper extremity motor function poststroke. DESIGN: Cross-sectional. SETTING: Participants' homes. PARTICIPANTS: A sample of people with stroke (N = 31). OUTCOMES AND MEASURES: Test-retest and interrater reliabilities were assessed through intraclass correlation coefficients (ICCs), Cohen's κ, standard error of measurement (SEM), and minimal detectable change (MDC). Interrater reliability validity was examined with Pearson and Spearman rank correlation coefficients. RESULTS: The ArmCAM (range = 0-30) consists of 10 items and takes 15 min to administer with no special equipment except for a computer and internet access. The ICCs for test-retest reliability and interrater reliability were .997 and .993, respectively. The SEM and MDC95 were 0.74 and 2.05 points, respectively. Individual items' test-retest reliability and interrater levels of agreement ranged from .811 to .957 and from .475 to .842, respectively, as measured with Cohen's κ. Correlations between the ArmCAM and the Rating of Everyday Arm-use in the Community and Home scale; the Stroke Impact Scale, hand function domain; the Fugl-Meyer Assessment for upper extremity; and the Action Research Arm Test were good to excellent. CONCLUSIONS AND RELEVANCE: The ArmCAM has good reliability and validity. It is an easy-to-use assessment designed to be administered remotely by means of videoconferencing. What This Article Adds: The ArmCAM is a psychometrically sound instrument that can be easily administered remotely by means of videoconferencing to evaluate upper extremity motor function after stroke.

Phase-dependent Brain Activation of the Frontal and Parietal Regions During Walking After Stroke - An fNIRS Study.

Background: Recovery of walking post-stroke is highly variable. Accurately measuring and documenting functional brain activation characteristics during walking can help guide rehabilitation. Previous work in this area has been limited to investigations of frontal brain regions and have not utilized recent technological and analytical advances for more accurate measurements. There were three aims for this study: to characterize the hemodynamic profile during walking post-stroke, to investigate regional changes in brain activation during different phases of walking, and to related brain changes to clinical measures. Methods: Functional near-infrared spectroscopy (fNIRS) along the pre-frontal, premotor, sensorimotor, and posterior parietal cortices was used on twenty individuals greater than six months post-stroke. Individual fNIRS optodes were digitized and used to estimate channel locations on each participant and short separation channels were used to control for extracerebral hemodynamic changes. Participants walked at their comfortable pace several times along a hallway while brain activation was recorded. Exploratory cluster analysis was conducted to determine if there was a link between brain activation and clinical measures. Results: Sustained activation was observed in the pre-frontal cortex with the ipsilesional hemisphere showing greater activation compared to the contralesional side. Sensorimotor cortex was active during the early, acceleration stage of walking only. Posterior parietal cortex showed changes in activation during the later, steady-state stage of walking. Faster gait speeds also related to increased activation in contralesional sensorimotor and posterior parietal cortices. Exploratory analysis clustered participants into two distinct groups based on their brain activation profiles and generally showed that individuals with greater activation tended to have better physical outcomes. Conclusions: These findings can guide future research for obtaining adequate power and determining factors that can be used as effect modifiers to reduce inter-subject variability. Overall, this is the first study to report specific oxygenated and deoxygenated hemoglobin changes in frontal to parietal regions during walking in the stroke population. Our results shed light on the importance of measuring brain activation across the cortex and show the importance of pre-frontal, sensorimotor, and posterior parietal cortices in walking after a stroke.

Frontal, Sensorimotor, and Posterior Parietal Regions Are Involved in Dual-Task Walking After Stroke.

Background: Walking within the community requires the ability to walk while simultaneously completing other tasks. After a stroke, completing an additional task while walking is significantly impaired, and it is unclear how the functional activity of the brain may impact this. Methods: Twenty individual in the chronic stage post-stroke participated in this study. Functional near-infrared spectroscopy (fNIRS) was used to measure prefrontal, pre-motor, sensorimotor, and posterior parietal cortices during walking and walking while completing secondary verbal tasks of varying difficulty. Changes in brain activity during these tasks were measured and relationships were accessed between brain activation changes and cognitive or motor abilities. Results: Significantly larger activations were found for prefrontal, pre-motor, and posterior parietal cortices during dual-task walking. Increasing dual-task walking challenge did not result in an increase in brain activation in these regions. Higher general cognition related to lower increases in activation during the easier dual-task. With the harder dual-task, a trend was also found for higher activation and less motor impairment. Conclusions: This is the first study to show that executive function, motor preparation/planning, and sensorimotor integration areas are all important for dual-task walking post-stroke. A lack of further brain activation increase with increasing challenge suggests a point at which a trade-off between brain activation and performance occurs. Further research is needed to determine if training would result in further increases in brain activity or improved performance.

Virtual Arm Boot Camp (V-ABC): study protocol for a mixed-methods study to increase upper limb recovery after stroke with an intensive program coupled with a grasp count device.

BACKGROUND: Encouraging upper limb use and increasing intensity of practice in rehabilitation are two important goals for optimizing upper limb recovery post stroke. Feedback from novel wearable sensors may influence practice behaviour to promote achieving these goals. A wearable sensor can potentially be used in conjunction with a virtually monitored home program for greater patient convenience, or due to restrictions that preclude in-person visits, such as COVID-19. This trial aims to (1) determine the efficacy of a virtual behaviour change program that relies on feedback from a custom wearable sensor to increase use and function of the upper limb post stroke; and (2) explore the experiences and perceptions of using a program coupled with wearable sensors to increase arm use from the perspective of people with stroke. METHODS: This mixed-methods study will utilize a prospective controlled trial with random allocation to immediate or 3-week delayed entry to determine the efficacy of a 3-week behaviour change program with a nested qualitative description study. The intervention, the Virtual Arm Boot Camp (V-ABC) features feedback from a wearable device, which is intended to increase upper limb use post stroke, as well as 6 virtual sessions with a therapist. Sixty-four adults within 1-year post stroke onset will be recruited from seven rehabilitation centres. All outcomes will be collected virtually. The primary outcome measure is upper limb use measured by grasp counts over 3 days from the wearable sensor (TENZR) after the 3-week intervention. Secondary outcomes include upper limb function (Arm Capacity and Movement Test) and self-reported function (Hand Function and Strength subscale from the Stroke Impact Scale). Outcome data will be collected at baseline, post-intervention and at 2 months retention. The qualitative component will explore the experiences and acceptability of using a home program with a wearable sensor for increasing arm use from the point of view of individuals with stroke. Semi-structured interviews will be conducted with participants after they have experienced the intervention. Qualitative data will be analysed using content analysis. DISCUSSION: This study will provide novel information regarding the efficacy and acceptability of virtually delivered programs to improve upper extremity recovery, and the use of wearable sensors to assist with behaviour change. TRIAL REGISTRATION: ClinicalTrials.gov NCT04232163 . January 18, 2020.

World Café- a community conversation: a Canadian perspective on stroke survivors needs for community integration.

BACKGROUND: Stroke is an acute condition that requires immediate care and long-term community-based chronic care supports. Communities vary in their ability to support the complex needs of this population. OBJECTIVES: To bring stroke recovery stakeholders together to discuss the needs of community-based stroke recovery and develop possible solutions across one province in Canada. METHODS: The participatory research approach of the World Café was used to explore topics related to community-based stroke recovery. Three World Cafés were held in three communities, including rural, urban-multicultural, and indigenous communities. Sixty-one stakeholders participated in this study. The data was analyzed following an inductive approach for all three Word Cafés. RESULTS: Four main themes were revealed from the data. First, Individual Needs, but Holistic Care encompassed the idea that stroke survivors' needs are complex and changing. Second, Whole of the Community indicated that all the people in stroke survivors' communities should be considered when designing solutions. Third, Transition in Care focused on the needs and solutions during the transition from hospital to community. Lastly, participants emphasized that better Connection, Collaboration, and Communication are needed among all stakeholders. CONCLUSIONS: While some similarities in needs and solutions were identified for stroke survivors across three diverse communities, differences between them were also reported. Approaches to enhance better communication among all stakeholders and facilitate a continuous transition from hospital to community are needed. Co-creating solutions with each local community should be considered as individual needs, and challenges are specific to each community.

Real-World Functional Grasping Activity in Individuals With Stroke and Healthy Controls Using a Novel Wearable Wrist Sensor.

Background. While wrist-worn accelerometers have been used to measure upper extremity use in the past, they primarily measure arm motion and lack the ability to capture functional hand opening and grasping activities which are essential for activities of daily living. Objectives. To characterize real-world functional hand opening and grasping activities captured over multiple days in adults with stroke and in matched controls using a novel wrist-worn device. Methods. Twenty-eight individuals (fourteen individuals with stroke and 14 healthy controls) wore the devices on both wrists for 3 days. Functional hand activity was characterized by daily hand counts, hourly hand counts, and asymmetry between hands. The Mann-Whitney U test was used to evaluate differences in functional hand activities between the two groups. Results. The stroke group had 1480 and 4691 daily hand counts in their affected and nonaffected hands, respectively. The control group had 3559 and 5021 daily hand counts in their nondominant and dominant hands, respectively. Significantly fewer daily hand counts (P = .019), fewer hourly hand counts (P = .024), and a larger asymmetry index (P = .01) of the affected hand in the stroke group were found compared to that of the nondominant hand in the control group. Conclusions. Real-world functional upper extremity activity can be measured using this novel wrist-worn device. Unlike wrist-worn accelerometers, this wrist-worn device can provide a measurement of functional grasping activity. The findings have implications for clinicians and researchers to monitor and assess real-world hand activity, as well as to apply specific doses of repetitions to improve neural recovery after stroke.

Implementation and Evaluation of the Virtual Graded Repetitive Arm Supplementary Program (GRASP) for Individuals With Stroke During the COVID-19 Pandemic and Beyond.

OBJECTIVE: Given the uncertainty of the coronavirus disease 2019 (COVID-19) pandemic, implementing telerehabilitation that enables the remote delivery of rehabilitation services is needed to mitigate the spread of COVID-19. We studied the implementation and the effectiveness of the virtual Graded Repetitive Arm Supplementary Program (GRASP) delivered and evaluated via videoconferencing in individuals with stroke. METHODS: The Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) framework with mixed methods was used to evaluate the implementation of the 2 iterations of the program delivered by a nonprofit organization during the pandemic. RESULTS: Reach: Seventeen people were screened, 13 people were eligible, and 11 consented to participate in the study. Effectiveness: Between baseline and posttest, participants with stroke demonstrated significant improvement in upper extremity function (Arm Capacity and Movement Test) and self-perceived upper extremity (UE) function (Stroke Impact Scale). Adoption: Factors that facilitate program uptake by the staff were well-planned implementation, appropriate screening procedure, and helpful feedback from the audits. All staff felt comfortable using videoconferencing technology to deliver the program despite some technical difficulties. Factors contributing to ongoing participation included that the participants liked the group, they perceived improvements, and the instructor was encouraging. Only one participant with stroke was not comfortable using the videoconferencing technology. Implementation: The program was implemented as intended as evaluated by a fidelity checklist. Participants' adherence was high, as verified by the average attendance and practice time. Maintenance: The organization continued to offer the program. CONCLUSION: The virtual GRASP program was successfully implemented. Although the program was effective in improving both measured and perceived UE function in a small sample of individuals with stroke, caution should be taken in generalizing the results. IMPACT: Implementing telerehabilitation is crucial to optimize patient outcomes and reduce the spread of COVID-19. Our findings provide guidance on the process of delivering a UE rehabilitation program remotely via videoconferencing for stroke. Moreover, insights that arise from this study also inform the implementation of other telerehabilitation services.

Implementation and Evaluation of the Graded Repetitive Arm Supplementary Program (GRASP) for People With Stroke in a Real World Community Setting: Case Report.

OBJECTIVE: Exercise programs to improve upper extremity function following stroke in the community setting are needed as the length of hospital stay continues to decrease. However, little has been done to increase understanding of how to translate an evidence-based rehabilitation intervention to real-world programs. The purpose of this case report was to describe a process evaluation of the implementation of an evidence-based upper extremity rehabilitation intervention for stroke, the Graded Repetitive Arm Supplementary Program, in a community setting. METHODS (CASE DESCRIPTION): A partnership between a nonprofit support organization and a local community center was established to deliver the program in the community. The Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) framework with mixed methods was used to evaluate the implementation. RESULTS: Reach: Twenty people were screened, 14 people met eligibility requirements, and 13 consented to participate. The program reached approximately 1.25% of the potential target population. Effectiveness: Participants with stroke demonstrated significant improvement in upper extremity function and quality of life as measured by the Fugl-Meyer Assessment for upper extremity, Action Research Arm Test, Rating of Everyday Arm-use in the Community and Home Scale, and Stroke Impact Scale. Adoption: Factors that facilitated program uptake were the well-planned implementation and the workplace coaching based on the audit results. Factors contributing to ongoing participation were the social support within the group environment and the instructor's capability of engaging the group. Implementation: A partnership between a nonprofit organization and a local community center was successfully established. The program was implemented as intended as verified by a fidelity checklist. Participant adherence was high as confirmed by the average attendance and practice time. Maintenance: Both the partner organization and community center continued to offer the program. CONCLUSION: The Graded Repetitive Arm Supplementary Program had good fidelity of the critical principles and core components and was effective in improving upper extremity function and quality of life. IMPACT: This partnership model may serve as the first step for future larger-scale implementation and could be used to move other stroke rehabilitation interventions into community settings.

Effects of transcranial direct current stimulation (tDCS) on posture, movement planning, and execution during standing voluntary reach following stroke.

BACKGROUND: Impaired movement preparation of both anticipatory postural adjustments and goal directed movement as shown by a marked reduction in the incidence of StartReact responses during a standing reaching task was reported in individuals with stroke. We tested how transcranial direct current stimulation (tDCS) applied over the region of premotor areas (PMAs) and primary motor area (M1) affect movement planning and preparation of a standing reaching task in individuals with stroke. METHODS: Each subject performed two sessions of tDCS over the lesioned hemisphere on two different days: cathodal tDCS over PMAs and anodal tDCS over M1. Movement planning and preparation of anticipatory postural adjustment-reach sequence was examined by startReact responses elicited by a loud acoustic stimulus of 123 dB. Kinetic, kinematic, and electromyography data were recorded to characterize anticipatory postural adjustment-reach movement response. RESULTS: Anodal tDCS over M1 led to significant increase of startReact responses incidence at loud acoustic stimulus time point - 500 ms. Increased trunk involvement during movement execution was found after anodal M1 stimulation compared to PMAs stimulation. CONCLUSIONS: The findings provide novel evidence that impairments in movement planning and preparation as measured by startReact responses for a standing reaching task can be mitigated in individuals with stroke by the application of anodal tDCS over lesioned M1 but not cathodal tDCS over PMAs. This is the first study to show that stroke-related deficits in movement planning and preparation can be improved by application of anodal tDCS over lesioned M1. Trial registration ClinicalTrial.gov, NCT04308629, Registered 16 March 2020-Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/NCT04308629.

Passive, yet not inactive: robotic exoskeleton walking increases cortical activation dependent on task.

BACKGROUND: Experimental designs using surrogate gait-like movements, such as in functional magnetic resonance imaging (MRI), cannot fully capture the cortical activation associated with overground gait. Overground gait in a robotic exoskeleton may be an ideal tool to generate controlled sensorimotor stimulation of gait conditions like 'active' (i.e. user moves with the device) and 'passive' (i.e. user is moved by the device) gait. To truly understand these neural mechanisms, functional near-infrared spectroscopy (fNIRS) would yield greater ecological validity. Thus, the aim of this experiment was to use fNIRS to delineate brain activation differences between 'Active' and 'Passive' overground gait in a robotic exoskeleton. METHODS: Fourteen healthy adults performed 10 walking trials in a robotic exoskeleton for Passive and Active conditions, with fNIRS over bilateral frontal and parietal lobes, and electromyography (EMG) over bilateral thigh muscles. Digitization of optode locations and individual T1 MRI scans were used to demarcate the brain regions fNIRS recorded from. RESULTS: Increased oxyhemoglobin in the right frontal cortex was found for Passive compared with Active conditions. For deoxyhemoglobin, increased activation during Passive was found in the left frontal cortex and bilateral parietal cortices compared with Active; one channel in the left parietal cortex decreased during Active when compared with Passive. Normalized EMG mean amplitude was higher in the Active compared with Passive conditions for all four muscles (p ≤ 0.044), confirming participants produced the conditions asked of them. CONCLUSIONS: The parietal cortex is active during passive robotic exoskeleton gait, a novel finding as research to date has not recorded posterior to the primary somatosensory cortex. Increased activation of the parietal cortex may be related to the planning of limb coordination while maintaining postural control. Future neurorehabilitation research could use fNIRS to examine whether exoskeletal gait training can increase gait-related brain activation with individuals unable to walk independently.

Cortical Activation During Shoulder and Finger Movements in Healthy Adults: A Functional Near-Infrared Spectroscopy (fNIRS) Study.

Characterization of cortical activation patterns during movement of the upper extremity in healthy adults is helpful in understanding recovery mechanisms following neurological disorders. This study explores cortical activation patterns associated with movements of the shoulder and fingers in healthy adults using functional near-infrared spectroscopy (fNIRS). Twelve healthy right-handed participants were recruited. Two motor tasks (shoulder abduction and finger extension) with two different trial lengths (10 s and 20 s) were performed in a sitting position at a rate of 0.5 Hz. The hemodynamic response, as indicated by oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR), over both hemispheres was acquired using a 54-channel fNIRS system. We found a generalized bilateral cortical activation during both motor tasks with greater activation in the contralateral compared to the ipsilateral primary motor cortex. Particularly in the more medial part of the contralateral hemisphere, significant higher activation was found during the shoulder compared to finger movements. Furthermore, cortical activation patterns are affected not only by motor tasks but also by trial lengths. HbO is more sensitive to detect cortical activation during finger movements in longer trials, while HbR is a better surrogate to capture active areas during shoulder movement in shorter trials. Based on these findings, reporting both HbO and HbR is strongly recommended for future fNIRS studies, and trial lengths should be taken into account when designing experiments and explaining results. Our findings demonstrating distinct cortical activation patterns associated with shoulder and finger movements in healthy adults provide a foundation for future research to study recovery mechanisms following neurological disorders.

Stepping characteristics during externally induced lateral reactive and voluntary steps in chronic stroke.

BACKGROUND: Stepping is critical for responding to perturbations, whether externally induced or self-initiated. Falls post-stroke is equally likely to happen from either mechanism. The objective of the study was, to examine lateral stepping performance during waist-pull induced reactive steps and voluntary choice reaction time steps in chronic stroke and controls. METHODS: In this cross-sectional study participants with chronic stroke (N = 10) and age- and gender-matched controls (N = 10) performed reactive and voluntary lateral steps. Step initiation time, global step length, step clearance, and step velocity were calculated. Other measures for reactive step included, Balance tolerance limit (perturbation magnitude when recovery transitioned from single to multiple steps), and step type. The Community Balance & Mobility Scale, and hip abductor and adductor isokinetic asymmetry torque ratio were assessed. RESULTS: The paretic and non-paretic leg were combined since step characteristics did not differ. Step (voluntary vs. reactive) by group (stroke vs. controls) was significant for step initiation time. The stroke group took longer initiating a voluntary step (P = 0.004). Reactive and voluntary steps were executed slower (P = 0.041), with a reduced step length (P = 0.028) by the stroke group. The stroke group had a lower balance tolerance limit (P = 0.01) and took reactive medial steps more frequently (P = 0.001). The Community Balance & Mobility Scale (P > 0.001), and hip abductor and adductor asymmetry torque ratio (P > 0.001; P = 0.015) was reduced in the stroke group. SIGNIFICANCE: Our findings indicate individuals post-stroke are slower initiating and executing reactive and voluntary steps. Though the reactive step timing is less impaired, this may be a method for enhancing faster voluntary movements and training reactive balance.

Impaired posture, movement preparation, and execution during both paretic and nonparetic reaching following stroke.

Posture and movement planning, preparation, and execution of a goal-directed reaching movement are impaired in individuals with stroke. No studies have shown whether the deficits are generally impaired or are specific to the lesioned hemisphere/paretic arm. This study utilized StartReact (SR) responses elicited by loud acoustic stimuli (LAS) to investigate the preparation and execution of anticipatory postural adjustments (APAs) and reach movement response during both paretic and nonparetic arm reaching in individuals with stroke and in age-matched healthy controls. Subjects were asked to get ready after receiving a warning cue and to reach at a "go" cue. An LAS was delivered at -500, -200, and 0 ms relative to the go cue. Kinetic, kinematic, and electromyographic data were recorded to characterize APA-reach movement responses. Individuals with stroke demonstrated systemwide deficits in posture and in movement planning, preparation, and execution of APA-reach sequence as shown by significant reduction in the incidence of SR response and impaired APA-reach performance, with greater deficits during paretic arm reaching. Use of trunk compensation strategy as characterized by greater involvement of trunk and pelvic rotation was utilized by individuals with stroke during paretic arm reaching compared with nonparetic arm reaching and healthy controls. Our findings have implications for upper extremity and postural control, suggesting that intervention should include training not only for the paretic arm but also for the nonparetic arm with simultaneous postural control requirements to improve the coordination of the APA-reach performance and subsequently reduce instability while functional tasks are performed during standing. NEW & NOTEWORTHY Our study is the first to show that nonparetic arm reaching also demonstrates impairment in posture and movement planning, preparation, and execution when performed during standing by individuals with stroke. In addition, we found compensatory trunk and pelvic rotations were used during a standing reach task for the paretic arms. The findings have clinical implications for upper extremity and postural rehabilitation, suggesting that training should include the nonparetic arms and incorporate simultaneous postural control demands.

Lateral Perturbation-Induced Stepping: Strategies and Predictors in Persons Poststroke.

BACKGROUND AND PURPOSE: Falls commonly occur as weight is transferred laterally, and impaired reactive stepping responses are associated with falls after stroke. The purpose of this study was to examine differences in and the determinants of mediolateral (M-L) protective stepping strategies when pulled off balance toward the paretic and nonparetic sides. METHODS: Eighteen individuals more than 6 months poststroke were pulled in the M-L direction by a lateral waist-pull perturbation system. Step type (crossover, medial, and lateral) and count were recorded, along with first-step initiation time, length, and clearance. Sensorimotor variables including hip adductor/abductor and ankle plantar flexor/dorsiflexor peak isokinetic torques, paretic foot plantar cutaneous sensation, and motor recovery were used to predict step type by discriminant function analyses (DFAs). RESULTS: Regardless of pull direction, nearly 70% of trials required 2 or more recovery steps, with more frequent nonparetic leg first steps, 63.5%. The step type was significantly different for pull direction (P = 0.005), with a greater percentage of lateral steps when pulled toward the nonparetic side (45.1%) compared with the paretic side (17.5%). The M-L step length of the lateral step was increased (P < 0.001), with a reduced step clearance (P = 0.05), when pulled toward the paretic side compared with a pull toward the nonparetic side. DFAs revealed that nonparetic and paretic-side pulls could respectively classify step type 64% and 60% of the time, with foot cutaneous sensation discriminating for pull direction. DISCUSSION AND CONCLUSIONS: Balance recovery initiated with the nonparetic leg occurred more frequently in response to M-L perturbations, and paretic foot cutaneous sensation was an important predictor of the stepping response regardless of the pull direction.Video Abstract available for more insights from the authors (see Video, Supplementary Digital Content 1, http://links.lww.com/JNPT/A190).

Impaired motor preparation and execution during standing reach in people with chronic stroke.

Movement preparation of both anticipatory postural adjustments (APAs) and goal directed movement during a standing reaching task in adults with chronic hemiparesis and healthy controls was investigated. Using a simple reaction time paradigm, while standing on two separate force platforms, subjects received a warning light cue to "get ready to reach" followed 2.5s later by an imperative light cue to "reach as quickly as possible" with the paretic arm (matched arm for controls) to touch a target in front of them for a total of 90 trials. In 30 of the reaching trials a loud acoustic stimulus (LAS) of 123 dB was randomly - -200, or 0ms relative to the "go" cue. APA (postural) responses were characterized by the onset and maximal posterior displacement of center of pressure (CoP) and onset/offset of electromyography (EMG) from tibialis anterior (TA), soleus (SOL), while reach was characterized by onset and maximal forward displacement of the reach hand and onset of the anterior (AD), biceps brachii (BB) and middle deltoid (MD). Subjects with stroke, demonstrated a marked reduction in the occurrence of the StartReact responses for both APA and forward reach at all LAS time points indicating movement preparation dysfunction. Movement execution during a cued reach showed significant delays in APA and reach onsets, significant reduction in the magnitude of APA (posterior CoP displacement) and reach excursion, and an increased latency between the APA and reach compared to controls. EMG activation patterns for the TA and SOL demonstrated co contraction compared to the temporally sequenced pattern of control subjects. When LAS was provided at the "go" there were earlier but not significant differences in APA onset latency compared to reaching without LAS and significant delays in reach onset latency when compared to control subjects with or without LAS. An early burst of EMG in biceps brachii muscles with a further delay of the reach onset compared to reaching without LAS may be indicative of interference of a classical startle reflex activating elbow flexors. Results indicated impairments in movement preparation of both APA's and goal directed UE movement in individuals with stroke which impact the functional performance of reaching in the standing position.