Reducing Abnormal Muscle Coactivation After Stroke Using a Myoelectric-Computer Interface

Apathy exacerbates postural control impairments in stroke survivors: The potential effects of cognitive dual-task for improving postural control

BackgroundHigh‐intensity occupational therapy can improve arm function after stroke, but many people lack access to such therapy. Home‐based therapies could address this need, but they don’t typically address abnormal muscle co‐activation, an important aspect of arm impairment. An earlier study using lab‐based, myoelectric computer interface game training enabled chronic stroke survivors to reduce abnormal co‐activation and improve arm function. Here, we assess feasibility of doing this training at home using a novel, wearable, myoelectric interface for neurorehabilitation training (MINT) paradigm.ObjectiveAssess tolerability and feasibility of home‐based, high‐dose MINT therapy in severely impaired chronic stroke survivors.MethodsTwenty‐three participants were instructed to train with the MINT and game for 90 min/day, 36 days over 6 weeks. We assessed feasibility using amount of time trained and game performance. We assessed tolerability (enjoyment and effort) using a customized version of the Intrinsic Motivation Inventory at the conclusion of training.ResultsParticipants displayed high adherence to near‐daily therapy at home (mean of 82 min/day of training; 96% trained at least 60 min/day) and enjoyed the therapy. Training performance improved and co‐activation decreased with training. Although a substantial number of participants stopped training, most dropouts were due to reasons unrelated to the training paradigm itself.InterpretationHome‐based therapy with MINT is feasible and tolerable in severely impaired stroke survivors. This affordable, enjoyable, and mobile health paradigm has potential to improve recovery from stroke in a variety of settings.Clinicaltrials.gov: NCT03401762.

Folate and MMA predict cognitive impairment in elderly stroke survivors: A cross sectional study

In this review, we aimed to identify the risk factors that may influence cognitive impairment among stroke survivors, namely, demographic, clinical, psychological, and physical determinants. A search from Medline, Scopus, and ISI Web of Science databases was conducted for papers published from year 2004 to 2015 related to risk factors of cognitive impairment among adult stroke survivors. A total of 1931 articles were retrieved, but only 27 articles met the criteria and were reviewed. In more than half of the articles it was found that demographical variables that include age, education level, and history of stroke were significant risk factors of cognitive impairment among stroke survivors. The review also indicated that diabetes mellitus, hypertension, types of stroke and affected region of brain, and stroke characteristics (e.g., size and location of infarctions) were clinical determinants that affected cognitive status. In addition, the presence of emotional disturbances mainly depressive symptoms showed significant effects on cognition. Independent relationships between cognition and functional impairment were also identified as determinants in a few studies. This review provided information on the possible risk factors of cognitive impairment in stroke survivors. This information may be beneficial in the prevention and management strategy of cognitive impairments among stroke survivors.

Survivors of Chronic Stroke Experience Continued Impairment of Dexterity But Not Strength in the Nonparetic Upper Limb

The purpose of this study was to quantify habitual dietary and systemic omega-6 and omega-3 fatty acids and their ratios and to determine their relationship with physical and metabolic function in a cohort of chronic adult stroke survivors. Twenty-five older chronic stroke survivors (age: 63 ± 8 years; BMI: 31 ± 7 kg/m2; mean ± SD) were assessed for fitness (VO2peak), gait speed (GS), 3 m timed up and go (TUG), and six-minute walk distance (6MWD). Plasma lipid and glucose profiles were measured, and HOMA-IR calculated. Dietary (5-day food records) and serum (mass spectrometry) omega-6/omega-3 profiles were assessed. Participants were severely deconditioned (VO2peak: 19 ± 4 mL/kg/min; GS: 0.88 ± 0.28 m/s; TUG: 12.6 ± 5.9 s; 6MWD: 295 ± 121 m) and at elevated metabolic risk (HOMA-IR: 6.3 ± 4.5). The dietary intake ratio of omega-6/omega-3 fatty acids averaged 12.6 ± 7.1 and the serum concentration ratio was 1.21 ± 0.37, which were correlated (r = 0.88, p < 0.01). Higher dietary intake and serum concentrations of omega-6/omega-3 fatty acids were associated with lower 6MWD and higher HOMA-IR, while a higher serum omega-6/omega-3 concentration index was associated with lower VO2peak (p’s < 0.05). These preliminary data suggest that both dietary omega-6 and omega-3 fatty acids (quantitated as their intake ratio) and the serum concentration ratio of omega-6/omega-3 may be important indices of physical dysfunction and insulin resistance in chronic stroke survivors.

Up to 50% of stroke survivors have persistent, severe upper extremity paresis even after receiving rehabilitation. Repetitive transcranial magnetic stimulation (rTMS) can augment the effects of rehabilitation by modulating corticomotor excitability, but the conventional approach of facilitating excitability of the ipsilesional primary motor cortex (iM1) fails to produce motor improvement in stroke survivors with severe loss of ipsilesional substrate. Instead, the undamaged, contralesional dorsal premotor cortex (cPMd) may be a more suitable target. CPMd can offer alternate, bi-hemispheric and ipsilateral connections in support of paretic limb movement. This pilot, randomized clinical trial seeks to investigate whether rTMS delivered to facilitate cPMd in conjunction with rehabilitation produces greater gains in motor function than conventional rTMS delivered to facilitate iM1 in conjunction with rehabilitation in severely impaired stroke survivors. Twenty-four chronic (≥6 months) stroke survivors with severe loss of ipsilesional substrate (defined by the absence of physiologic evidence of excitable residual pathways tested using TMS) will be included. Participants will be randomized to receive rTMS to facilitate cPMd or iM1 in conjunction with task-oriented upper limb rehabilitation given for 2 sessions/week for 6 weeks. Assessments of primary outcome related to motor impairment (upper extremity Fugl-Meyer [UEFM]), motor function, neurophysiology, and functional neuroimaging will be made at baseline and at 6-week end-of-treatment. An additional assessment of motor outcomes will be repeated at 3-month follow-up to evaluate retention. The primary endpoint is 6-week change in UEFM. This pilot trial will provide preliminary evidence on the effects and mechanisms associated with facilitating intact cPMd in chronic severe stroke survivors. The trial is registered on clinicaltrials.gov, NCT03868410.

Upper-limb paresis is the most common motor impairment post stroke. Current solutions to automate the assessment of upper-limb impairment impose a number of critical burdens on patients and their caregivers that preclude frequent assessment. In this work, we propose an approach to estimate upper-limb impairment in stroke survivors using two wearable inertial sensors, on the wrist and the sternum, and a minimally-burdensome motor task. Twenty-three stroke survivors with no, mild, or moderate upper-limb impairment performed two repetitions of one-to-two minute-long continuous, random (i.e., patternless), voluntary upper-limb movements spanning the entire range of motion. The three-dimensional time-series of upper-limb movements were segmented into a series of one-dimensional submovements by employing a unique movement decomposition technique. An unsupervised clustering algorithm and a supervised regression model were used to estimate Fugl-Meyer Assessment (FMA) scores based on features extracted from these submovements. Our regression model estimated FMA scores with a normalized root mean square error of 18.2% ( r2=0.70 ) and needed as little as one minute of movement data to yield reasonable estimation performance. These results support the possibility of frequently monitoring stroke survivors' rehabilitation outcomes, ultimately enabling the development of individually-tailored rehabilitation programs.

Hyperexcitability of spinal motoneurons may contribute to muscular hypertonia after hemispheric stroke. The origins of this hyperexcitability are not clear, but we hypothesized that prolongation of the Ia excitatory postsynaptic potential (EPSP) in spastic motoneurons may be one potential mechanism, by enabling more effective temporal summation of Ia EPSPs, making action potential initiation easier. Thus, the purpose of this study is to quantify the time course of putative EPSPs in spinal motoneurons of chronic stroke survivors. To estimate the EPSP time course, a pair of low-intensity electrical stimuli was delivered sequentially to the median nerve in seven hemispheric stroke survivors and in six intact individuals, to induce an H-reflex response from the flexor carpi radialis muscle. H-reflex response probability was then used to quantify the time course of the underlying EPSPs in the motoneuron pool. A population EPSP estimate was then derived, based on the probability of evoking an H-reflex from the second test stimulus in the absence of a reflex response to the first conditioning stimulus. Our experimental results showed that in six of seven hemispheric stroke survivors, the apparent rate of decay of the population EPSP was markedly slower in spastic compared with contralateral (stroke) and intact motoneuron pools. There was no significant difference in EPSP time course between the contralateral side of stroke survivors and control subject muscles. We propose that one potential mechanism for hyperexcitability of spastic motoneurons in chronic stroke survivors may be associated with this prolongation of the Ia EPSP time course. Our subthreshold double-stimulation approach could provide a noninvasive tool for quantifying the time course of EPSPs in both healthy and pathological conditions. NEW & NOTEWORTHY Spastic motoneurons in stroke survivors showed a prolonged Ia excitatory postsynaptic potential (EPSP) time course compared with contralateral and intact motoneurons, suggesting that one potential mechanism for hyperexcitability of spastic motoneurons in chronic stroke survivors may be associated with this prolongation of the Ia EPSP time course.

Combining Cyproheptadine Hydrochloride With Targeted Muscle Activation Training to Treat Upper Extremity Stroke: A Randomized, Placebo-Controlled Trial

Chronic stroke survivors often regain walking speed but continue to exhibit heightened gait variability, increasing fall risk. This study investigated the effects of a 12-week moderate-to-high intensity muscle strengthening program on gait parameters and their variability in stroke survivors, without incorporating gait-specific training. Stroke survivors participated in a twice-weekly, 45-60 min strengthening program using Pilates equipment. Spatiotemporal gait parameters were measured before and after the intervention using 3D motion capture. Walking speed, cadence, step/stride length, step width, and various temporal parameters were analyzed for both paretic and non-paretic limbs, along with their coefficients of variation (CV). Correlation analyses were performed to understand the relationships between parameter changes. Eleven patients (age 61 ± 7.4 years, 9 males) participated in the study. Significant improvements were observed in walking speed for both paretic (0.61 to 0.69 m/s, p = 0.032) and non-paretic limbs (0.62 to 0.69 m/s, p = 0.024). Step length significantly increased in the paretic limb (0.36 to 0.41 m, p = 0.042) with a substantial reduction in variability (CV: 19.91% to 14.99%). Cadence increased significantly in the non-paretic limb (89.24 to 92.01 steps/min, p = 0.024). Correlation analysis revealed distinct adaptation patterns between limbs, with speed improvements strongly associated with stride length in both limbs, but with step length only in the non-paretic limb. A moderate-to-high intensity strengthening program, even without direct gait training, can improve walking speed and reduce movement variability in chronic stroke survivors. The intervention predominantly influenced the spatial parameters, with modest changes in the temporal aspects, suggesting that enhanced force production and control primarily affect step execution while preserving temporal gait patterns.

Introduction: Stroke is the leading cause of prolonged disability worldwide. Today, as we face another pandemic, there is a gap between stroke survivors and the healthcare services they need. With that, the researchers aim to identify the impact of Strokecoach application as part of the blended rehabilitation program in managing stroke survivors. Methods: The study utilized an experimental descriptive design to evaluate the application's weaknesses and strengths. Fifteen chronic stroke survivors and five physical therapists participated in the data collection for four weeks. Results: Results suggested that stroke survivors and physical therapists are strongly satisfied with the application. In terms of compliance in exercise performance, the stroke respondents were described as compliant and fully compliant in the blood pressure monitoring. The quality of life and the feasibility of the application as part of the blended rehabilitation program have also been found to be effective. Discussion: Physical therapists recommend this application as a partner in treating chronic stroke survivors. It will serve as a benchmark in revolutionizing Physical therapy telerehabilitation in the Philippines and integrate the use of a mobile application as part of the intervention. It is recommended for future studies to have more participants and more extended time to improve the analysis.

Electrical impedance myography (EIM) is a sensitive assessment for neuromuscular diseases to detect muscle inherent properties, whereas surface electromyography (sEMG) is a common technique for monitoring muscle activation. However, the application of EIM in detecting training effects on stroke survivors is relatively few. This study aimed to evaluate the muscle inherent properties and muscle activation alteration after functional electrical stimulation (FES)-assisted cycling training to chronic stroke survivors. Fifteen people with chronic stroke were recruited for 20 sessions of FES-assisted cycling training (40 min/session, 3–5 sessions/week). The periodically stimulated and assessed muscle groups were quadriceps (QC), tibialis anterior (TA), hamstrings (HS), and medial head of gastrocnemius (MG) on the paretic lower extremity. EIM parameters [resistance (R), reactance (X), phase angle (θ), and anisotropy ratio (AR)], clinical scales (Fugl-Meyer Lower Extremity (FMA-LE), Berg Balance Scale (BBS), and 6-min walking test (6MWT)] and sEMG parameters [including root-mean square (RMS) and co-contraction index (CI) value] were collected and computed before and after the training. Linear correlation analysis was conducted between EIM and clinical scales as well as between sEMG and clinical scales. The results showed that motor function of the lower extremity, balance, and walking performance of subjects improved after the training. After training, θ value of TA (P = 0.014) and MG (P = 0.017) significantly increased, and AR of X (P = 0.004) value and AR of θ value (P = 0.041) significantly increased on TA. The RMS value of TA decreased (P = 0.022) and a significant reduction of CI was revealed on TA/MG muscle pair (P < 0.001). Significant correlation was found between EIM and clinical assessments (AR of X value of TA and FMA-LE: r = 0.54, P = 0.046; X value of TA and BBS score: 0.628, P = 0.016), and between sEMG and clinical scores (RMS of TA and BBS score: r = −0.582, P = 0.029). This study demonstrated that FES-assisted cycling training improved lower limb function by developing coordinated muscle activation and facilitating an orderly myofiber arrangement. The current study also indicated that EIM can jointly evaluate lower extremity function alteration with sEMG after rehabilitation training.Clinical Trail Registration: The study was registered on the Clinical Trial Registry (trial registration number: NCT 03208439, https://clinicaltrials.gov/ct2/show/NCT03208439).

This study aimed to explore the relationship between training volume during 4weeks of robot-assisted arm training (RAAT) and changes in arm-and hand function, grip strength, gross motor skills, spasticity, and daily activities. Twenty participants, >18years of age, in subacute phase following stroke, with impaired arm function admitted to Sunnaas Rehabilitation Hospital, completed 4weeks robot-assisted arm training (45min, 3-5 times a week). Before and after this intervention, the participants' arm and hand function, grip strength, gross motor dexterity, spasticity and activities of daily living were assessed. The key findings of this study indicated no association between training volume and improvements in arm and hand function, grip strength, gross motor dexterity, spasticity, or activities of daily living. Also, no significant associations between changes in arm and hand function and age, gender, or affected side. However, subgroup analysis showed significant improvements in arm-hand function for participants with shorter time post-stroke (p = 0.01) and better initial arm and hand function (p < 0.0001). These findings highlight the importance of early initiation and individualized treatment based on initial function when using robot-assisted arm training in stroke survivors.

We characterized the passive mechanical properties of the affected and contralateral musculotendon units in 9 chronic stroke survivors as well as in 6 neurologically-intact controls. Using a position-controlled motor, we precisely indented the distal tendon of the biceps brachii to a 20 mm depth from skin, recording both its sagittal motion using ultrasound movies and the compression force at the tip of the indenter. Length changes of 8 equally-spaced features along the aponeurosis axis were quantified using a pixel-tracking protocol. We report that, on the aggregate and with respect to contralateral and control, respectively, the affected side initiates feature motion at a shorter indentation distance by 61% and 50%, travels further by 15% and 9%, at a lower rate of 28% and 15%, and is stiffer by 40% and 57%. In an extended analysis including the spatial location of the 8 designated features, we report that in contrast to the contralateral and control muscles, the affected musculotendon unit does not strain measurably within the imaging window. These results confirm that chronic stroke-induced spasticity changes musculotendon unit passive mechanics, causing it to not strain under stretch. The mechanisms responsible for altered passive mechanics may lie within extracellular matrix fibrosis.