Post-stroke Participants Research Articles

Single Nucleotide Polymorphisms May Increase the Risk of Aspiration Pneumonia in Post-Stroke Patients with Dysphagia.

This study aimed to evaluate whether genetic polymorphism is associated with an increased risk of infection, specifically post-stroke aspiration pneumonia. Blood samples were obtained from a total of 206 post-stroke participants (males, n = 136; mean age, 63.8 years). Genotyping was performed for catechol-O-methyltransferase (rs4680, rs165599), dopamine receptors (DRD1; rs4532, DRD2; rs1800497, DRD3; rs6280), brain-derived neurotrophic factor (rs6265), apolipoprotein E (rs429358, rs7412), and the interleukin-1 receptor antagonist gene (rs4251961). The subjects were stratified into two groups, aged < 65 (young) and ≥ 65 (elderly). Functional parameters and swallowing outcomes were measured at enrollment and at 3 months post-onset. The primary outcome was the incidence of aspiration pneumonia. Analysis of the association between genetic polymorphisms and aspiration pneumonia history showed that a minor C rs429358 allele was associated with the occurrence of aspiration pneumonia in the young group, both in the additive and the dominant models (odds ratio: 4.53; 95% CI: 1.60–12.84, p = 0.004). In the multivariable analysis, the minor C rs429358 allele increased the risk of post-stroke aspiration pneumonia in young stroke patients by 5.35 (95% CI: 1.64–20.88). In contrast, no such association was observed in the elderly group. Apolipoprotein E polymorphism may affect the risk of post-stroke aspiration pneumonia.

Aberrant beta-band brain connectivity predicts speech motor planning deficits in post-stroke aphasia

Impairments in speech production can have devastating effects on the overall quality of life in left-hemisphere stroke survivors with aphasia; however, there is a paucity of research focusing on neural deficits in speech motor planning networks that are activated prior to the onset of speech production in this clinical population. In the present study, we examined directional brain connectivity correlates of speech preparation and planning in low-β (13–20 Hz) and high-β (21–30 Hz) band neural oscillations in participants aphasia compared with controls prior to the onset of speech. Electroencephalographic (EEG) data were concurrently recorded from 33 participants with post-stroke aphasia and 22 neurologically intact controls while they engaged in speech production tasks. Using Granger causality, brain connectivity was calculated between electrode pairs that fell within fronto-frontal, fronto-central, and fronto-parietal networks implicated in sensorimotor integration and speech planning. Clinical assessment was further conducted in post-stroke participants to measure the severity of language impairment associated with aphasia. Increased intra-hemispheric connectivity was found within low- and high-β bands in the left parieto-central and parieto-frontal as well as the right fronto-frontal and fronto-central electrodes in post-stroke participants compared with controls prior to the onset of speech production. In addition, we found that decreased inter-hemispheric centro-central connectivity within high-β band was negatively correlated with aphasia severity whereas increased parieto-frontal connectivity within high-β band was positively correlated with aphasia severity. These findings suggest that participants with left-hemisphere stroke express aberrant brain connectivity within low- and high-β bands in both left and right hemispheres during the planning phase of speech production, and that these deficits are associated with specific aspects of their language impairment, as indicated by their clinical symptoms due to aphasia.

Can people with poststroke insomnia benefit from blended cognitive behavioral therapy? A single case experimental design.

Sleep is essential for our overall health and wellbeing. Unfortunately, stroke often induces insomnia, which has been shown to impede rehabilitation and recovery of function. Cognitive behavioral therapy for insomnia (CBT-I) is the treatment of choice for insomnia in the general population and is efficacious both when delivered face-to-face or online. The primary aim of this study was to evaluate efficacy of blended CBT-I (eCBT-I) in five poststroke participants with insomnia according to DSM-5 criteria. A randomized multiple baseline design was used to evaluate improvements in total sleep time, sleep onset latency, sleep efficiency, nocturnal awakenings and sleep quality. The intervention included six weeks of eCBT-I combined with two face-to-face sessions. All participants completed the intervention. One participant stopped using the diary, while the other four completed it fully. All five sleep diary measures improved, significantly so for nocturnal awakenings. Moreover, after completion of the treatment, four out of five participants no longer fulfilled DSM-5 criteria for insomnia disorder. This is the first study to show that blended CBT-I is potentially effective in participants with post-stroke insomnia. The findings justify extension to a randomized controlled trial.

Timing of propulsion-related biomechanical variables is impaired in individuals with post-stroke hemiparesis

BackgroundIn individuals with post-stroke hemiparesis, reduced paretic leg propulsion, measured through anterior ground reaction forces (AGRF), is a common and functionally-relevant gait impairment. Deficits in other biomechanical variables such as plantarflexor moment, ankle power, and ankle excursion contribute to reduced propulsion. While reduction in the magnitude of propulsion post-stroke is well studied, here, our objective was to compare the timing of propulsion-related biomechanical variables. Research questionAre there differences in the timing of propulsion and propulsion-related biomechanical variables between able-bodied individuals, the paretic leg, and non-paretic leg of post-stroke individuals? MethodsNine able-bodied and 13 post-stroke individuals completed a gait analysis session comprising treadmill walking trials at each participant’s self-selected speed. Two planned independent sample t-tests were conducted to detect differences in the timing of dependent variables between the paretic versus non-paretic leg post-stroke and paretic leg versus the dominant leg of able-bodied individuals. ResultsPost-stroke individuals demonstrated significantly earlier timing of peak AGRF of their paretic leg versus their non-paretic leg and able-bodied individuals. Post-stroke participants displayed earlier timing of peak power of their paretic leg versus their non-paretic leg and able-bodied individuals, and earlier timing of peak ankle moment of the paretic leg versus able-bodied. No significant differences were detected in the timing of peak ankle angle. SignificanceThe earlier onset of peak AGRF, peak ankle power, and peak ankle moment may be an important, under-studied biomechanical factor underlying stroke gait impairments, and a potential therapeutic target for stroke gait retraining. Future investigations can explore the use of interventions such as gait biofeedback to normalize the timing of these peaks, thereby improving propulsion and walking function post-stroke.

Can Individuals Poststroke Improve Their Performance in Reaction and Movement Times in a Nonimmersive Serious Game with Practice? A Cross-Sectional Study.

Objective: To verify if individuals' poststroke and healthy controls would improve their performance in reaction and movement times practicing a serious game task using the upper limb movements. Materials and Methods: We evaluated 30 individuals poststroke and 30 healthy controls, matched for age and sex. We used the "Association Game for Rehabilitation" (AGaR) where participants played by matching a pair of images whose meanings were similar. Hand movements were captured by a Kinect system and poststroke participants used their nonparetic upper limb. Reaction time and movement times (time to select an image and movement time to the target) were measured. Data were analyzed using multiple analysis of variance. Results: Performance improved for both groups across all variables with better performance in movement times than reaction time only for poststroke individuals. Conclusions: Upper limb movements using nonimmersive serious games enhanced motor performance in reaction and movement times for healthy controls and individuals poststroke. ReBEC Trial Registration: RBR-4m4pk; Registeted on 08/24/2018.

A Novel Virtual Reality Training Strategy for Poststroke Patients: A Randomized Clinical Trial.

Stroke patients suffer impairments including sensory, motor, visual, and cognitive areas, as well as gait and balance manifestations making activities of daily living difficult. In such conditions, virtual reality training can be a potential rehabilitation tool in comparison to conventional physical therapy to cater to the burden of this disability; hence, this randomized clinical trial compared the effects of virtual reality training and conventional physical therapy on balance and lower extremity function in stroke patients. The sample of 68 poststroke participants from Kanaan Physical Therapy and Spine Clinic, Lahore, Pakistan, were divided into N = 34 cases each using the lottery method with one group given virtual reality training and the other received conventional physical therapy. Each group received 60 minutes intervention, 3 days per week for 6 weeks. The Berg balance scale and the Fugl-Meyer assessment-lower extremity scale were employed for data collection preintervention, immediate postintervention, and 6 weeks postintervention. The statistically significant differences between virtual reality and conventional physical therapy groups for the Berg Balance score (p < 0.001), Fugl-Meyer assessment (FMA)-lower extremity domains of FMA-motor function (p < 0.001), FMA-joint pain, and joint range (p < 0.001); however, there is no significant difference (p=0.202) for time vs. group interaction and significant (p < 0.001) for the time main effect for FMA sensation. Hence, virtual reality training is more effective to restore balance and lower extremity function compared to conventional physical therapy in stroke patients. The results of the study have significant implications for the clinicians with better case management enhancing quality of life of patients along with the dearth of local literature, thus providing base for future research from a developing country's perspective.

Classifying Unimanual and Bimanual Upper Extremity Tasks in Individuals Post-Stroke.

After stroke, many individuals develop impairments that lead to compensatory motions. Compensation allows individuals to achieve tasks but has long-term detrimental effects and represents maladaptive motor strategies. Increased use of bimanual motions may serve as a biomarker for recovery (and the reduction of reliance on compensatory motion), and tracking such motion using sensor data may provide critical data for health care specialists. However, past work by the authors demonstrated individual variation in motor strategies results in noisy and chaotic sensor data. The goal of the current work is to develop classifiers capable of differentiating unimanual, bimanaual asymmetric, and bimanual symmetric gestures using wearable sensor data. Twenty participants post-stroke (and 20 age-matched controls) performed a set of tasks under the supervision of a trained occupational therapist. Sensor data were recorded for each task. Classifiers were developed using artificial neural networks (ANNs) as a baseline, and the echo state neural network (ESNN) which has demonstrated efficacy with chaotic data. We find that, for control and post-stroke participants, the ESNN results in improved testing accuracy performance (91.3% and 80.3%, respectively). These results suggest a novel method for classifying gestures in individuals post-stroke, and the developed classifiers may facilitate longitudinal monitoring and correction of compensatory motion.

A-136 The Transfer of Cognitive Training to Real-World Functioning: Results of our First Six Pilot Subjects at Six-Month Follow-Up

Abstract Objective Currently, the majority of cognitive training research measures treatment efficacy using in-laboratory measures, with minimal focus on real-world treatment changes. This case series demonstrates the feasibility of transferring cognitive improvements from the laboratory into the everyday life setting. Method This case series includes 6 chronic post-stroke participants; mild to moderate cognitive impairment. The intervention combines cognitive training with behavioral techniques, known as the Transfer Package (TP). The TP involves components that target functionality on IADLs in the real-world. Performance on cognitively-based IADLs in the real world are measured pre-treatment, post, and 6-month follow-up. Measures of real-world ability are the: Canadian Occupational Performance Measure (COPM), Cognitive Task Activity Log (CTAL) and Inventory of Improved and New Abilities (INCA). In-laboratory measures included the D-KEFS and Timed IADL assessments. Results The real-world outcome measures used in this study were the COPM and two measures developed for this study, the CTAL and INCA. The mean change from pre to post on the COPM Performance Scale was 2.18 (SD = 1.33) and the mean change on the COPM Satisfaction Scale was 2.70 (SD = 1.27). The mean change on the CTAL was 1.96 (SD = 0.93). On the INCA, the mean number of improved real-world cognitive activities was 11.8 (SD = 4.9) and the mean number of new cognitive activities was 7.6 (SD = 3.9). Follow-up reported near-perfect retention on CTAL and continued improvement on the INCA. There were minimal changes on in-laboratory measures. Conclusions This case series provides a framework for achieving the transfer of cognitive training treatment effects in the real-world life situation by overcoming behavioral barriers to functioning.

Revisiting Spasticity After Stroke: Clustering Clinical Characteristics for Identifying At-Risk Individuals.

PurposeTo collectively identify the clinical characteristics determining the risk of developing spasticity after stroke.Patients and MethodsA cross-sectional study was conducted at a single rehabilitation outpatient clinic from June to December 2019. Inclusion criteria were stroke duration of over four weeks, aged 18 years and above. Exclusion criteria were presence of concurrent conditions other than stroke that could also lead to spasticity. Recruited patients were divided into “Spasticity” and “No spasticity” groups. Univariate analysis was deployed to identify significant predictive spasticity factors between the two groups followed by a two-step clustering approach for determining group of characteristics that collectively contributes to the risk of developing spasticity in the “Spasticity” group.ResultsA total of 216 post-stroke participants were recruited. The duration after stroke (p < 0.001) and the absence of hemisensory loss (p = 0.042) were two significant factors in the “Spasticity” group revealed by the univariate analysis. From a total of 98 participants with spasticity, the largest cluster of individuals (40 patients, 40.8%) was those within less than 20 months after stroke with moderate stroke and absence of hemisensory loss, while the smallest cluster was those within less than 20 months after severe stroke and absence of hemisensory loss (21 patients, 21.4%).ConclusionAnalyzing collectively the significant factors of developing spasticity may have the potential to be more clinically relevant in a heterogeneous post-stroke population that may assist in the spasticity management and treatment.

Adiponectin Concentration and Chronic Stroke Individuals, Associations with Body Composition, Physical Activity Levels and Lipid Profile: A Cross-Sectional Explorative Study

ObjectiveHigher adiponectin concentration has been associated with the presence of sarcopenia in individuals with cardiovascular diseases. Post-stroke individuals presented higher adiponectin concentrations than non-stroke ones. However, no previous study has investigated the association between the adiponectin concentration and skeletal muscle mass in post-stroke individuals. On the other hand, higher adiponectin concentration has been associated with a more favorable lipid profile and the physical activity level might regulate adiponectin concentration. These associations have not been studied in this population. Thus, the main objective of this study was to determine whether the adiponectin concentration is associated with: (1) body composition; (2) lipid profile; and (3) physical activity level in chronic post-stroke individuals. Materials and MethodsThis study was a correlational, cross-sectional exploratory study. Data on body composition and lipid profile were collected using a bioelectrical impedance analyzer (InBody® 720) and an automated method analyzer (CELL-DYN Ruby), respectively. The physical activity level was measured by the StepWatch® Activity Monitor and the serum adiponectin concentration was analyzed using an enzyme-linked immunosorbent assay kit. Correlation analyses were made using Spearman's rank correlation coefficient (rs). ResultsTwenty-one post-stroke participants took part in the study. The adiponectin concentration was associated with the following: skeletal muscle mass (rs = -0.78), skeletal muscle mass index (rs = -0.75) and high-density lipoprotein (rs = 0.43). ConclusionsA greater adiponectin concentration is associated with a lower skeletal muscle mass and a higher high-density lipoprotein level in chronic post-stroke individuals, but not with physical activity levels.

Tongue and Lip Comparisons between Healthy and Nondysphagic Poststroke Individuals

Background: The lips and tongue play a substantial role in efficient clearance of food from the mouth and pharynx into the esophagus. No study has compared oral pressures between healthy individuals and poststoke individuals who report functional swallow abilities. Aim: The current study aimed to investigate the presence of differences in oral pressures between healthy individuals and poststroke individuals who report functional swallowing abilities. Design: This is a controlled matched pair study. Population: Eighteen control participants (CG) and 18 nondysphagic poststroke participants (NDSG) were enrolled into this study. Methods: The Iowa Oral Performance Instrument (IOPI) was used to measure and compare tongue strength, endurance, and functional lingual and labial pressures between sex and age-matched pairs. Results: Six paired, two-tailed t tests revealed that tongue and lip pressures were different between the 2 groups. Maximum anterior tongue pressures and posterior tongue pressures were also different, i.e., t(17) = –2.89 (p = 0.010) and t(17) = –2.85 (p = 0.011), with the CG presenting higher pressures. Right lip pressures were significantly lower in the NDSG compared to the CG, i.e., t(17) = 2.45 (p = 0.0001). Left lip pressures were significantly lower in the NDSG compared to the CG, i.e., t(17) = –5.43 (p = 0.0001). Tongue endurance, i.e., t(17) = 0.092 (p = 0.928) and saliva swallow pressures, i.e., t(17) = –0.490 (p = 0.63) were not different. Conclusion: Although poststroke participants reported functional swallowing abilities, there were differences in tongue and lip pressures but not in endurance or saliva swallow pressures. Clinical Rehabilitation Impact: Poststroke individuals without complaints of dysphagia who are not assessed may experience subclinical dysphagia that could negatively impact their nutrition and quality of life.

U-Limb: A multi-modal, multi-center database on arm motion control in healthy and post-stroke conditions.

BackgroundShedding light on the neuroscientific mechanisms of human upper limb motor control, in both healthy and disease conditions (e.g., after a stroke), can help to devise effective tools for a quantitative evaluation of the impaired conditions, and to properly inform the rehabilitative process. Furthermore, the design and control of mechatronic devices can also benefit from such neuroscientific outcomes, with important implications for assistive and rehabilitation robotics and advanced human-machine interaction. To reach these goals, we believe that an exhaustive data collection on human behavior is a mandatory step. For this reason, we release U-Limb, a large, multi-modal, multi-center data collection on human upper limb movements, with the aim of fostering trans-disciplinary cross-fertilization.ContributionThis collection of signals consists of data from 91 able-bodied and 65 post-stroke participants and is organized at 3 levels: (i) upper limb daily living activities, during which kinematic and physiological signals (electromyography, electro-encephalography, and electrocardiography) were recorded; (ii) force-kinematic behavior during precise manipulation tasks with a haptic device; and (iii) brain activity during hand control using functional magnetic resonance imaging.

THE ASSOCIATIONS BETWEEN HYPERTENSION AND STROKE FROM MAY MEASUREMENT MONTH AND BETWEEN NATIONAL HYPERTENSION PARAMETERS WITH STROKE MORTALITY FROM THE GLOBAL BURDEN OF DISEASE

Objective: To characterise the association between stroke history and hypertension from the 2017 and 2018 May Measurement Month (MMM) blood pressure (BP) screening campaigns. To identify whether national-level MMM hypertension parameters are associated with national stroke mortality statistics. Design and method: Three BP readings and self-reported demographic, lifestyle and cardiovascular risk factors were collected from 2,515,578 participants in 95 countries. National stroke mortality statistics and Socio-Demographic Index (SDI) were extracted from the Global Burden of Disease (GBD) study 2017. Hypertension was defined as a raised BP (systolic BP &gt; = 140 mmHg or diastolic BP &gt; = 90 mmHg based on the mean of the second and third readings), or on antihypertensive medication. Multiple imputation using chained equations was performed to estimate mean BP readings where missing. Logistic and linear regression were applied, respectively, to the association between hypertension and stroke and between national-level GBD stroke mortality with MMM proportions with raised, treated and uncontrolled BP. Results: Low-middle-SDI countries in MMM had the highest age-sex standardised proportion of participants with a previous stroke (4.9%), compared with high-middle-SDI countries (1.4%). Globally, individuals with a history of stroke had a significantly higher mean BP than those without (6.6/1.7 mmHg higher, p &lt; 0.001). Amongst post-stroke participants, antihypertensive medication appeared to mitigate the impact of lifestyle factors on the odds of hypertension. Stroke mortality increased, on average, by 34 per 100,000 per 1% increase in the proportion of untreated individuals with raised BP (p = 0.006) and by 22 per 100,000 per 1% increase in proportion with treated but uncontrolled BP (p = 0.003). Stroke mortality decreased, on average, by 14 per 100,000 per 1% increase in the proportion of hypertensives treated (p = 0.01). Conclusions: Our study found suboptimal BP control among participants with a previous stroke globally, especially in low SDI countries. There was a significant association between national stroke mortality from GBD and the proportions of participants with raised or uncontrolled BP and of hypertensives treated in MMM. This suggests that despite lacking a population-based design, estimates from MMM broadly reflect rates of downstream mortality and that opportunistic screening can be an effective means of screening for hypertension.

Postural Assessment Scale for Stroke Patients in Acute, Subacute and Chronic Stage: A Construct Validity Study.

(1) Background: Observational scales are the most common methodology used to assess postural control and balance in people with stroke. The aim of this paper was to analyse the construct validity of the Postural Assessment Scale for Stroke Patients (PASS) scale in post-stroke patients in the acute, subacute, and chronic stroke phases. (2) Methods: Sixty-one post-stroke participants were enrolled. To analyze the construct validity of the PASS, the following scales were used: the Functional Ambulatory Category (FAC), the Wisconsin Gait Scale (WGS), the Barthel Index (BI) and the Functional Independence Measure (FIM). (3) Results: The construct validity of the PASS scale in patients with stroke at acute phase was moderate with the FAC (r = −0.791), WGS (r = −0.646) and FIM (r = −0.678) and excellent with the BI (r = 0.801). At subacute stage, the construct validity of the PASS scale was excellent with the FAC (r = 0.897), WGS (r = −0.847), FIM (r = −0.810) and BI (r = −0.888). At 6 and 12 months, the construct validity of the PASS with the FAC, WGS, FIM and BI was also excellent. (4) Conclusions: The PASS scale is a valid instrument to assess balance in post-stroke individuals especially, in the subacute and chronic phases (at 6 and 12 months).

Investigating On-Road Lane Maintenance and Speed Regulation in Post-Stroke Driving: A Pilot Case-Control Study.

Stroke can adversely affect the coordination and judgement of drivers due to executive dysfunction, which is relatively common in the post-stroke population but often undetected. Quantitatively examining vehicle control performance in post-stroke driving becomes essential to inspect whether and where post-stroke older drivers are risky. To date, it is unclear as to which indicators, such as lane keeping or speed control, can differentiate the driving performance of post-stroke older drivers from that of normal (neurotypical) older drivers. By employing a case–control design using advanced vehicle movement tracking and analysis technology, this pilot study aimed to compare the variations in driving trajectory, lane keeping and speed control between the two groups of older drivers using spatial and statistical techniques. The results showed that the mean standard deviation of lane deviation (SDLD) in post-stroke participants was higher than that of normal participants in complex driving tasks (U-turn and left turn) but almost the same in simple driving tasks (straight line sections). No statistically significant differences were found in the speed control performance. The findings indicate that, although older drivers can still drive as they need to after a stroke, the decline in cognitive abilities still imposes a higher cognitive workload and more effort for post-stroke older drivers. Future studies can investigate post-stroke adults’ driving behaviour at more challenging driving scenarios or design driving intervention programs to improve their executive function in driving.

Optimal Multifield Functional Electrical Stimulation Parameters for the “Turn on the Light” Task and Related Upper Limb Kinematics Repeatability in Poststroke Subjects

ObjectiveTo characterize the optimal functional electrical stimulation (FES) parameters that assist the turn on the light task (TOTL) on poststroke participants and to analyze the related upper limb (UL) kinematics repeatability. DesignCross-sectional study. SettingHuman movement research center. ParticipantsPoststroke individuals (N=11) with history of a single unilateral stroke that resulted in a motor control dysfunction of the contralesional UL. InterventionsFES based on surface multifield technology applied to the contralesional wrist and finger extensors during the TOTL. Main Outcome MeasuresFES outcome metrics (virtual electrodes, stimulation duration, intensity) and kinematic metrics (end-point kinematics [absolute and relative duration, mean and peak velocities, relative instant of peak velocity, index of curvature, number of movement units] and joint kinematics [shoulder, elbow, wrist end position and range of movement]). Outcome measures were assessed 2 times with a 72-hour maximum time interval. ConclusionIt was possible to establish reliable FES parameters that assisted the TOTL on poststroke participants. These stimulation parameters led to high to very high repeatability in terms of UL kinematics for most of the cases.

Determining the effect of stair nosing shape on foot trajectory during stair ambulation in healthy and post-stroke individuals

Stair design can influence the risk of stair falls. Stair nosings are intended to provide greater foot accommodation, although to date little is known about how the nosing shape can affect foot trajectory during stair ambulation. This study investigates the impact of different nosing shapes (round, square, tapered, and no nosing) on foot clearance and overhang measures during stair ascent and descent among healthy and post-stroke older adults. Slower cadence in ascent and descent, and greater foot overhang during descent highlighted the increased risk of stair falls for persons with chronic stroke. For both healthy and post-stroke participants, the tapered and round nosing shapes resulted in the largest horizontal foot clearance, and smallest foot overhang, respectively. However, given the greater step-to-step variability detected with round nosings, the tapered nosing presents as the safest choice among all evaluated designs. The results of this work can be used to inform architectural and accessible design standards for a safer built environment.

Underlying mechanisms of oxygen uptake kinetics in chronic post-stroke individuals: A correlational, cross-sectional pilot study.

Post-stroke individuals presented deleterious changes in skeletal muscle and in the cardiovascular system, which are related to reduced oxygen uptake ([Formula: see text]) and take longer to produce energy from oxygen-dependent sources at the onset of exercise (mean response time, MTRON) and during post-exercise recovery (MRTOFF). However, to the best of our knowledge, no previous study has investigated the potential mechanisms related to [Formula: see text] kinetics response (MRTON and MRTOFF) in post-stroke populations. The main objective of this study was to determine whether the MTRON and MRTOFF are related to: 1) body composition; 2) arterial compliance; 3) endothelial function; and 4) hematological and inflammatory profiles in chronic post-stroke individuals. Data on oxygen uptake ([Formula: see text]) were collected using a portable metabolic system (Oxycon Mobile®) during the six-minute walk test (6MWT). The time to achieve 63% of [Formula: see text] during a steady state (MTRON) and recovery (MRTOFF) were analyzed by the monoexponential model and corrected by a work rate (wMRTON and wMRTOFF) during 6MWT. Correlation analyses were made using Spearman's rank correlation coefficient (rs) and the bias-corrected and accelerated bootstrap method was used to estimate the 95% confidence intervals. Twenty-four post-stroke participants who were physically inactive took part in the study. The wMRTOFF was correlated with the following: skeletal muscle mass (rs = -0.46), skeletal muscle mass index (rs = -0.45), augmentation index (rs = 0.44), augmentation index normalized to a heart rate of 75 bpm (rs = 0.64), reflection magnitude (rs = 0.43), erythrocyte (rs = -0.61), hemoglobin (rs = -0.54), hematocrit (rs = -0.52) and high-sensitivity C-reactive protein (rs = 0.58), all p < 0.05. A greater amount of oxygen uptake during post-walking recovery is partially related to lower skeletal muscle mass, greater arterial stiffness, reduced number of erythrocytes and higher systemic inflammation in post-stroke individuals.

Examining recruitment feasibility and related outcomes in adults post-stroke

BackgroundThere are limited effective and evidence-based interventions for upper extremity hemiparesis post-stroke. To prepare for an RCT and minimize misuse of resources, there is value in conducting a feasibility study.ObjectiveTo examine the feasibility of recruitment and other related outcomes for an intense upper limb intervention.MethodologyFeasibility outcomes included retention, adherence, accrual rate, sample characteristics, and identification of productive recruitment methods. Other outcomes included satisfaction with the study, fidelity, and equipoise of both staff and participants.ResultsParticipants were enrolled at a rate of 1.33 per month. The recruitment timeline had to be extended by 4 months, to meet the target of 16 randomized participants. Staggered recruitment was the most successful strategy. We found that following up with individuals who missed initial appointments prior to study enrollment led to decreased adherence.ConclusionIt is feasible to recruit and retain post-stroke participants for an intense intervention study.Trial registrationNCT02277028

Gait Adaptation Using a Cable-Driven Active Leg Exoskeleton (C-ALEX) With Post-Stroke Participants

Individuals with chronic hemiparesis post-stroke exhibit gait impairments that require functional rehabilitation through training. Exoskeletal robotic assistive devices can provide a user with continuous assistance but impose movement restrictions. There are currently devices that allow unrestricted movement but provide assistance only intermittently at specific points of the gait cycle. Our design, a cable-driven active leg exoskeleton (C-ALEX), allows the user both unrestricted movement and continuous force assistance throughout the gait cycle to assist the user in new walking patterns. In this study, we assessed the ability of C-ALEX to induce a change in the walking patterns of ten post-stroke participants using a single-session training protocol. The ability of C-ALEX to accurately provide forces and torques in the desired directions was also evaluated to compare its design performance to traditional rigid-link designs. Participants were able to reach 91% ± 12% of their target step length and 89% ± 13% of their target step height. The achieved step parameters differed significantly from participant baselines ( ). To quantify the performance, the forces in each cable's out of the plane movements were evaluated relative to the in-plane desired cable tension magnitudes. This corresponded to an error of under 2Nm in the desired controlled joint torques. This error magnitude is low compared to the system command torques and typical adult biological torques during walking (2-4%). These results point to the utility of using non-restrictive cable-driven architectures in gait retraining, in which future focus can be on rehabilitating gait pathologies seen in stroke survivors.