Safety & efficacy of a robotic hip exoskeleton on outpatient stroke rehabilitation.

OBJECTIVE: The objective of this study was to analyze the safety and efficacy of using a robotic hip exoskeleton designed by Samsung Electronics Co., Ltd., Korea, called the Gait Enhancing and Motivating System-Hip (GEMS-H), in assistance mode only with the poststroke population in an outpatient-rehabilitation setting. METHODS: Forty-one participants with an average age of 60 and average stroke latency of 6.5 years completed this prospective, single arm, interventional, longitudinal study during the COVID-19 pandemic. Significant modifications to the traditional outpatient clinical environment were made to adhere to organizational physical distancing policies as well as guidelines from the Centers for Disease Control. All participants received gait training with the GEMS-H in assistance mode for 18 training sessions over the course of 6-8 weeks. Performance-based and self-reported clinical outcomes were assessed at four time points: baseline, midpoint (after 9 training sessions), post (after 18 training sessions), and 1-month follow up. Daily step count was also collected throughout the duration of the study using an ankle-worn actigraphy device. Additionally, corticomotor excitability was measured at baseline and post for 4 bilateral lower limb muscles using transcranial magnetic stimulation. RESULTS: By the end of the training program, the primary outcome, walking speed, improved by 0.13 m/s (p < 0.001). Secondary outcomes of walking endurance, balance, and functional gait also improved as measured by the 6-Minute Walk Test (47 m, p < 0.001), Berg Balance Scale (2.93 points, p < 0.001), and Functional Gait Assessment (1.80 points, p < 0.001). Daily step count significantly improved with and average increase of 1,750 steps per day (p < 0.001). There was a 35% increase in detectable lower limb motor evoked potentials and a significant decrease in the active motor threshold in the medial gastrocnemius (-5.7, p < 0.05) after training with the device. CONCLUSIONS: Gait training with the GEMS-H exoskeleton showed significant improvements in walking speed, walking endurance, and balance in persons with chronic stroke. Day-to-day activity also improved as evidenced by increased daily step count. Additionally, corticomotor excitability changes suggest that training with this device may help correct interhemispheric imbalance typically seen after stroke. TRIAL REGISTRATION: This study is registered with ClinicalTrials.gov (NCT04285060).

Barriers to Enrollment in a Post-Stroke Neuromodulation and Walking Study: Implications for Recruiting Women.

BACKGROUND: Women have a higher risk of stroke and related disability than men but are underrepresented in stroke clinical trials. Identifying modifiable recruitment and enrollment barriers for women can improve study generalizability, statistical power, and resource utilization. OBJECTIVE: In a post-stroke neuromodulation study, we determined the impact of sex on the occurrence of exclusion criteria and compared the sex distribution of screened and enrolled individuals with a broader stroke-affected population. METHODS: A total of 335 individuals with chronic stroke were screened for a study examining how neuromodulation and high-intensity treadmill training affect walking speed and corticomotor excitability. Demographics and exclusions were retrospectively gathered as a secondary dataset. Exclusion criteria consisted of 6 categories (not target population, unable to do treadmill protocol, unable to do non-invasive brain stimulation, insufficient ankle motion and disinterest, and cognitive impairment). Incidence of each exclusion criterion was compared between women and men. The sex distribution was compared to a dataset from Chicago primary stroke centers. RESULTS: A total of 81 individuals were enrolled and 254 were not. The percentage of women excluded was significantly greater than that of men (P = .04). No individual exclusion criterion or categories excluded women more frequently than men. Screened and enrolled individuals had a lower proportion of women and younger age than a representative stroke population (P < .001). CONCLUSIONS: We identified exclusion criteria (ie, headaches, cognitive scores, and age) that are modifiable barriers to enrollment of women in this post-stroke neuromodulation study. Addressing underrepresentation of women in stroke research is pivotal for enhancing generalizability, achieving statistical power, and optimizing resources.

The association of interlimb coordination and temporal symmetry with walking function and motor impairment after stroke.

OBJECTIVE: Interlimb coordination during walking is impaired after stroke, with unknown effects on walking function. This cross-sectional study determined associations of interlimb coordination and temporal symmetry with walking function and motor impairment. DESIGN: During walking, participants wore wireless sensors to detect heel strikes. We calculated interlimb coordination as the phase coordination index and temporal symmetry as the ratio of contralesional (i.e., paretic) to ipsilesional (i.e., non-paretic) stance times. Associations with walking speed (10-meter walk test), walking endurance (6-minute walk test), dynamic balance (Mini Balance Evaluation Systems Test), and motor impairment (Fugl Meyer Lower Extremity assessment) were assessed. RESULTS: 56 individuals with chronic stroke were tested. Worse interlimb coordination was correlated with slower comfortable (R = -0.38, p = 0.004) and maximal (R = -0.36, p = 0.006) walking speed and worse motor function (R = -0.45, p = 0.001). Worse temporal symmetry was correlated with worse motor function (R = 0.39, p = 0.004). Interlimb coordination had stronger associations than temporal symmetry with comfortable (R: -0.38 vs. 0.08) and maximal walking speeds (R: -0.36 vs. 0.12). CONCLUSION: Poor interlimb coordination was associated with slow walking and motor impairment and had stronger associations with walking speeds than temporal symmetry did. Interlimb coordination may provide unique insights into walking function and a target for walking rehabilitation after stroke.

Concurrent validity of walking speed measured by a wearable sensor and a stopwatch during the 10-meter walk test in individuals with stroke.

BACKGROUND: Walking speed is often measured with a stopwatch throughout stroke recovery. Wearable sensors also have been used recently to measure walking speed and provide information about spatiotemporal characteristics of walking. RESEARCH QUESTION: Do walking speeds measured with stopwatch and APDM wearable sensors have concurrent validity? METHODS: Individuals with chronic stroke (n = 62) performed the 10-meter walk test at comfortable and maximal speeds. Walking speeds were measured with a stopwatch and APDM Opal wireless wearable sensors (3-unit). Tests of concurrent validity between stopwatch and APDM (Bland-Altman plots, systematic and proportional bias, and intraclass correlations) and test-retest reliability between trials (intraclass correlations, standard error of measurement, and minimal detectable change) were performed. RESULTS: Walking speeds measured with APDM were ∼0.07 m/s slower than those measured with stopwatch (systematic bias; t ≥ 13.1, p < 0.001). Intraclass correlations ranged from poor to excellent. There were greater differences in walking speeds between APDM and stopwatch for individuals with faster walking speeds (proportional bias). Test-retest reliability was excellent for both APDM and stopwatch (intraclass correlation≥0.94). Standard error of measurement ranged from 0.04 to 0.07 m/s and minimal detectable change ranged from 0.10 to 0.19 m/s. SIGNIFICANCE: It may be inappropriate to use walking speed measurements from APDM sensors and stopwatch interchangeably in individuals with chronic stroke. Differences in walking speeds may reflect stopwatch error or the derivation of walking speed from wearable sensors. Test-retest reliability was excellent for both stopwatch and APDM, but minimal detectable change values were large. Large changes in walking speed may be required to be confident that the change is a true and clinically meaningful change and not measurement error. The validity and reliability of measuring walking speed with wearable sensors in individuals with chronic stroke has important implications for determining community ambulation, assessing improvements after rehabilitation, and developing exercise prescriptions.