Neural correlates of walking post-stroke: neuroimaging insights from the past decade.

Walking dysfunction such as slow walking speed and reduced independent mobility are common impairments following stroke. Neural mechanisms of upper limb impairment and motor recovery have been highly studied, while less is known about the neural correlates of walking dysfunction and rehabilitation after stroke. Our objective was to review the literature on neuroimaging correlates of walking and walking recovery post-stroke to provide a more comprehensive picture of neurological regions of interest. We searched the databases PubMed, CINAHL, Web of Science, and Cochrane Trials for articles published in English between January 1, 2010 and November 30, 2020 that assessed walking after stroke through neuroimaging and various clinical measures. The following key words were used: stroke, gait, walking, rehabilitation, brain mapping, neuroimaging, neural control of walking, motor recovery and motor function, and resulted in eighteen articles included in this review. These articles revealed regions of interest associated with lower extremity impairment and walking post-stroke to include the putamen, caudate, insula, pallidum, superior temporal gyrus, internal capsule, superior longitudinal fasciculus, corticospinal tract, corona radiata, and white matter associated with the pedunculopontine nucleus. This information strengthens our understanding of supraspinal control of walking post-stroke. However, future research on lesion location, functional and structural connectivity, and walking deficits is needed to confidently associate specific brain regions and white matter tracts/connectivity with specific impairments. Greater insight into neuromechanisms associated with response to neurorehabilitation post-stroke could improve treatment selection and prediction of motor recovery.

Utilization of wearable technology to assess gait and mobility post-stroke: a systematic review.

BACKGROUND: Extremity weakness, fatigue, and postural instability often contribute to mobility deficits in persons after stroke. Wearable technologies are increasingly being utilized to track many health-related parameters across different patient populations. The purpose of this systematic review was to identify how wearable technologies have been used over the past decade to assess gait and mobility in persons with stroke. METHODS: We performed a systematic search of Ovid MEDLINE, CINAHL, and Cochrane databases using select keywords. We identified a total of 354 articles, and 13 met inclusion/exclusion criteria. Included studies were quality assessed and data extracted included participant demographics, type of wearable technology utilized, gait parameters assessed, and reliability and validity metrics. RESULTS: The majority of studies were performed in either hospital-based or inpatient settings. Accelerometers, activity monitors, and pressure sensors were the most commonly used wearable technologies to assess gait and mobility post-stroke. Among these devices, spatiotemporal parameters of gait that were most widely assessed were gait speed and cadence, and the most common mobility measures included step count and duration of activity. Only 4 studies reported on wearable technology validity and reliability metrics, with mixed results. CONCLUSION: The use of various wearable technologies has enabled researchers and clinicians to monitor patients' activity in a multitude of settings post-stroke. Using data from wearables may provide clinicians with insights into their patients' lived-experiences and enrich their evaluations and plans of care. However, more studies are needed to examine the impact of stroke on community mobility and to improve the accuracy of these devices for gait and mobility assessments amongst persons with altered gait post-stroke.

Daily acute intermittent hypoxia to improve walking function in persons with subacute spinal cord injury: a randomized clinical trial study protocol.

BACKGROUND: Restoring community walking remains a highly valued goal for persons recovering from traumatic incomplete spinal cord injury (SCI). Recently, studies report that brief episodes of low-oxygen breathing (acute intermittent hypoxia, AIH) may serve as an effective plasticity-inducing primer that enhances the effects of walking therapy in persons with chronic (> 1 year) SCI. More persistent walking recovery may occur following repetitive (weeks) AIH treatment involving persons with more acute SCI, but this possibility remains unknown. Here we present our clinical trial protocol, designed to examine the distinct influences of repetitive AIH, with and without walking practice, on walking recovery in persons with sub-acute SCI (< 12 months) SCI. Our overarching hypothesis is that daily exposure (10 sessions, 2 weeks) to AIH will enhance walking recovery in ambulatory and non-ambulatory persons with subacute (< 12 months) SCI, presumably by harnessing endogenous mechanisms of plasticity that occur soon after injury. METHODS: To test our hypothesis, we are conducting a randomized, placebo-controlled clinical trial on 85 study participants who we stratify into two groups according to walking ability; those unable to walk (non-ambulatory group) and those able to walk (ambulatory group). The non-ambulatory group receives either daily AIH (15, 90s episodes at 10.0% O2 with 60s intervals at 20.9% O2) or daily SHAM (15, 90s episodes at 20.9% O2 with 60s intervals at 20.9% O2) intervention. The ambulatory group receives either 60-min walking practice (WALK), daily AIH + WALK, or daily SHAM+WALK intervention. Our primary outcome measures assess overground walking speed (10-Meter Walk Test), endurance (6-Minute Walk Test), and balance (Timed Up & Go Test). For safety, we also measure levels of pain, spasticity, systemic hypertension, and autonomic dysreflexia. We record outcome measures at baseline, days 5 and 10, and follow-ups at 1 week, 1 month, 6 months, and 12 months post-treatment. DISCUSSION: The goal of this clinical trial is to reveal the extent to which daily AIH, alone or in combination with task-specific walking practice, safely promotes persistent recovery of walking in persons with traumatic, subacute SCI. Outcomes from this study may provide new insight into ways to enhance walking recovery in persons with SCI. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02632422 . Registered 16 December 2015.

Long-term impact of mild traumatic brain injury on postural stability and executive function.

OBJECTIVE: A substantial number of individuals present with prolonged symptoms after a mild traumatic brain injury (mTBI) or concussion. This has warranted the development of assessment tools that can reliably detect prolonged symptoms after an mTBI. At present, a gold standard diagnostic tool for accurately identifying such prolonged symptoms is not available. The purpose of this study is to utilize specific measures of standing balance, cognitive function, and bimanual coordination to examine persisting long-term deficits in individuals with mTBI. METHODS: A total of 18 (medically diagnosed with an mTBI within the last year) and 14 (healthy age-matched controls) individuals participated in the study. Assessment tools included NIH Toolbox Cognition Battery (NIHTB-CB), TEMPA, and Purdue pegboard (bimanual coordination) and standing balance on a force platform. RESULTS: Individuals with mTBI demonstrated lower scores in all measures of cognition with statistically significant difference (p = 0.03) in executive function. The clinical tests of bimanual coordination did not show any statistically significant differences between groups. Postural stability was significantly reduced (p = 0.039) in the mTBI group. CONCLUSION: Our results show long-term performance deficits (cognition and postural stability) that persist in individuals with mTBI. In addition, to the best of our knowledge, this is the first study to identify cognitive deficits in individuals with mTBI by utilizing NIHTB-CB. Knowledge gained from this study might affect decisions of return-to-play or return-to-learn in individuals with a history of mTBI(s).

Cortical disconnection of the ipsilesional primary motor cortex is associated with gait speed and upper extremity motor impairment in chronic left hemispheric stroke.

Advances in neuroimaging have enabled the mapping of white matter connections across the entire brain, allowing for a more thorough examination of the extent of white matter disconnection after stroke. To assess how cortical disconnection contributes to motor impairments, we examined the relationship between structural brain connectivity and upper and lower extremity motor function in individuals with chronic stroke. Forty-three participants [mean age: 59.7 (±11.2) years; time poststroke: 64.4 (±58.8) months] underwent clinical motor assessments and MRI scanning. Nonparametric correlation analyses were performed to examine the relationship between structural connectivity amid a subsection of the motor network and upper/lower extremity motor function. Standard multiple linear regression analyses were performed to examine the relationship between cortical necrosis and disconnection of three main cortical areas of motor control [primary motor cortex (M1), premotor cortex (PMC), and supplementary motor area (SMA)] and motor function. Anatomical connectivity between ipsilesional M1/SMA and the (1) cerebral peduncle, (2) thalamus, and (3) red nucleus were significantly correlated with upper and lower extremity motor performance (P ≤ 0.003). M1-M1 interhemispheric connectivity was also significantly correlated with gross manual dexterity of the affected upper extremity (P = 0.001). Regression models with M1 lesion load and M1 disconnection (adjusted for time poststroke) explained a significant amount of variance in upper extremity motor performance (R2  = 0.36-0.46) and gait speed (R2  = 0.46), with M1 disconnection an independent predictor of motor performance. Cortical disconnection, especially of ipsilesional M1, could significantly contribute to variability seen in locomotor and upper extremity motor function and recovery in chronic stroke. Hum Brain Mapp 39:120-132, 2018. © 2017 Wiley Periodicals, Inc.

Individuals with chronic traumatic brain injury improve walking speed and mobility with intensive mobility training.

OBJECTIVE: To determine the feasibility and impact of different dosages of Intensive Mobility Training (IMT) on mobility, balance, and gait speed in individuals with chronic traumatic brain injury (TBI). DESIGN: Prospective, single group design with 3-month follow-up. SETTING: University research laboratory. PARTICIPANTS: Volunteer sample of participants with chronic TBI (N=10; ≥3 mo post-TBI; able to ambulate 3.05 m with or without assistance; median age, 35.4 y; interquartile range, 23.5-46 y; median time post-TBI, 9.91 y; interquartile range, 6.3-14.2 y). Follow-up data were collected for all participants. INTERVENTIONS: Twenty days (5 d/wk for 4 wk), with 150 min/d of repetitive, task-specific training equally divided among balance; gait training; and strength, coordination, and range. MAIN OUTCOME MEASURES: Pain and fatigue were recorded before and after each session to assess feasibility. Treatment outcomes were assessed before training (pre), after 10 sessions (interim), after 20 sessions (post), and at 3-months follow-up and included the Berg Balance Scale and gait speed. RESULTS: Participants averaged 150.1±2.7 minutes per session. Median presession and postsession pain scores were 0 (out of 10) for 20 sessions; median presession fatigue scores ranged from 0 to 2.5 (out of 10); and postsession scores ranged from 3 to 5.5 (out of 10). Four outcome measures demonstrated significant improvement from the pretest to interim, with 7 out of 10 participants exceeding the minimal detectable change (MDC) for fast walking speed. At the posttest, 2 additional measures were significant, with more participants exceeding the MDCs. Changes in fast walking speed and Timed Up and Go test were significant at follow-up. CONCLUSIONS: Limited fluctuations in pain and fatigue scores indicate feasibility of IMT in this population. Participants demonstrated improvements in walking speed, mobility, and balance postintervention and maintained gains in fast walking speed and mobility at 3 months.

Body weight-supported treadmill training is no better than overground training for individuals with chronic stroke: a randomized controlled trial.

BACKGROUND: Body weight-supported treadmill training (BWSTT) has produced mixed results compared with other therapeutic techniques. OBJECTIVE: The purpose of this study was to determine whether an intensive intervention (intensive mobility training) including BWSTT provides superior gait, balance, and mobility outcomes compared with a similar intervention with overground gait training in place of BWSTT. METHODS: Forty-three individuals with chronic stroke (mean [SD] age, 61.5 [13.5] years; mean [SD] time since stroke, 3.3 [3.8] years), were randomized to a treatment (BWSTT, n = 23) or control (overground gait training, n = 20) group. Treatment consisted of 1 hour of gait training; 1 hour of balance activities; and 1 hour of strength, range of motion, and coordination for 10 consecutive weekdays (30 hours). Assessments (step length differential, self-selected and fast walking speed, 6-minute walk test, Berg Balance Scale [BBS], Dynamic Gait Index [DGI], Activities-specific Balance Confidence [ABC] scale, single limb stance, Timed Up and Go [TUG], Fugl-Meyer [FM], and perceived recovery [PR]) were conducted before, immediately after, and 3 months after intervention. RESULTS: No significant differences (α = 0.05) were found between groups after training or at follow-up; therefore, groups were combined for remaining analyses. Significant differences (α = 0.05) were found pretest to posttest for fast walking speed, BBS, DGI, ABC, TUG, FM, and PR. DGI, ABC, TUG, and PR results remained significant at follow-up. Effect sizes were small to moderate in the direction of improvement. CONCLUSIONS: Future studies should investigate the effectiveness of intensive interventions of durations greater than 10 days for improving gait, balance, and mobility in individuals with chronic stroke.

Counting repetitions: an observational study of video game play in people with chronic poststroke hemiparesis.

BACKGROUND AND PURPOSE: The use of video gaming as a therapeutic intervention has increased in popularity; however, the number of repetitions in comparison with traditional therapy methods has yet to be investigated. The primary purpose of this study was to document and compare the number of repetitions performed while playing 1 of 2 video gaming systems for a time frame similar to that of a traditional therapy session in individuals with chronic stroke. METHODS: Twelve participants with chronic stroke (mean age, 66.8 ± 8.2 years; time poststroke, 19.2 ± 15.4 months) completed video game play sessions, using either the Nintendo Wii or the Playstation 2 EyeToy. A total of 203 sessions were captured on video record; of these, 50 sessions for each gaming system were randomly selected for analysis. For each selected record, active upper and lower extremity repetitions were counted for a 36-minute segment of the recorded session. RESULTS: The Playstation 2 EyeToy group produced an average of 302.5 (228.1) upper extremity active movements and 189.3 (98.3) weight shifts, significantly higher than the Nintendo Wii group, which produced an average of 61.9 (65.7) upper extremity active movements and 109.7 (78.5) weight shifts. No significant differences were found in steps and other lower extremity active movements between the 2 systems. DISCUSSION AND CONCLUSIONS: The Playstation 2 EyeToy group produced more upper extremity active movements and weight shifting movements than the Nintendo Wii group; the number and type of repetitions varied across games. Active gaming (specifically Playstation 2 EyeToy) provided more upper extremity repetitions than those reported in the literature by using traditional therapy, suggesting that it may be a modality to promote increased active movements in individuals poststroke.

Active video-gaming effects on balance and mobility in individuals with chronic stroke: a randomized controlled trial.

BACKGROUND: Treatments that provide feedback, increase practice with multiple repetitions, and motivate patients are essential to rehabilitation post stroke. OBJECTIVE: To determine whether playing active video games results in improved balance and mobility post stroke. METHODS: Thirty participants with chronic (time since stroke = 3.0 [2.9] years) hemiparesis post stroke were randomly assigned to a gaming group or normal activity control group. Gaming systems provided participants with an interactive interface of real-time movement of either themselves or an avatar on the screen. Participants played games 50-60 minutes/day, 4 days/week, for 5 weeks. The intervention was strictly game-play, in standing position, without physical therapy. The control group received no special intervention and continued with normal activity. Both groups were tested prior to, following the 5 weeks (post test), and 3 months following the completion of the study. Outcome measures included the Fugl-Meyer Assessment, Berg Balance Scale, Dynamic Gait Index, Timed Up & Go, 6-minute walk test, 3-meter walk (self-selected and fast), and perception of recovery. RESULTS: No statistically significant differences between or within groups were found through analysis of covariance (covaried for side of hemiparesis) at post test or follow-up. Although the within-group effect sizes were primarily indexed as "small" (< .36), the gaming group exhibited higher within-group effect sizes before and after testing than did the control group on all 7 dependent variables analyzed. CONCLUSIONS: Even though the only intervention was game-play, there were small positive effects. Therapist assistance in making more optimum movement choices may be needed before significant improvements are seen with commercially available, general purpose games.

Exploring the implementation potential of physical activity assessment and prescription tools in physical therapy practice: a mixed-method study.

BACKGROUND: Despite the benefits of physical activity (PA), especially related to aging, physical therapists do not perform regular PA prescriptions secondary to various barriers, including lack of tools. Therefore, we developed the Inventory of Physical Activity Barriers (IPAB). OBJECTIVE: Explore potential solutions that could address the current lack of PA prescription among United States-based physical therapists treating patients 50 years and older. METHOD: A convergent parallel mixed-method design consisting of focus groups and self-report questionnaires. Descriptive statistics were used for all quantitative variables. Focus groups were thematically coded. RESULTS: The 26 participants had 8.6 years (SD = 6.4) of clinical experience, 88.4% (n = 23) reported they regularly have PA conversations with patients, 65.4% (n = 17) regularly assess PA levels, and 19.2% (n = 5) regularly provide PA prescriptions. We identified three themes: 1) opportunities and challenges related to PA prescriptions; 2) lack of standardization in PA assessments and interventions; and 3) implementation potential for innovative solutions that address the current informal PA assessments and interventions. CONCLUSION: Physical therapists are amenable to incorporating innovative solutions that support physical activity prescription behavior. Therefore, we recommend the continued development and implementation of PA assessment and prescription tools.

Physical Activity and Physical Activity Participation Barriers Among Adults 50 Years and Older During the COVID-19 Pandemic.

OBJECTIVE: We examined changes in physical activity from pre-COVID-19 to during the COVID-19 pandemic and the factors associated with reduced physical activity levels among adults 50 yrs and older. DESIGN: Participants of a validation study were stratified into being "less active than before" or "equally or more active than before" COVID-19. Multivariable manual backward analyses were used to identify self-reported barriers associated with the reduction in physical activity. RESULTS: Reduced physical activity levels during COVID-19 were reported among 244 of 503 participants (43%). After adjusting for demographics and health conditions, factors that increased the odds of reduced physical activity levels during COVID-19 were lacking access to workout places, feeling too anxious, and difficulty committing to physical activity. Factors that decreased the odds of reduced physical activity levels during COVID-19 were self-identifying a heart- or lung-associated diagnosis that impacts physical activity and having a 12-mo retrospective history of falling. CONCLUSIONS: The physical activity participation barriers identified to be associated with a reduction in physical activity can be used as a starting point for a conversation regarding physical activity participation during COVID-19. TO CLAIM CME CREDITS: Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME. CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Describe the changes in physical activity levels among adults 50 yrs and older from pre-COVID-19 to during the COVID-19 pandemic; (2) Differentiate between the COVID-19 related factors associated with reduced physical activity levels among adults 50 yrs and older and younger adults; and (3) Identify the physical activity-related factor that decreased the odds of reduced physical activity levels during COVID-19 among adults 50 yrs and older. LEVEL: Advanced. ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s) ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Acute effects of axial loading on postural control during walking and turning in people with multiple sclerosis: A pilot study.

BACKGROUND: Impaired sensory integration is heavily involved in gait control and accentuates fall risk in individuals with multiple sclerosis (MS). While axial loading has been found beneficial, little is known about the effect of non-specific axial loads on gait parameters and mobility tasks in those with MS. RESEARCH QUESTION: What are the effects of non-specific axial loading via weighted vests on walking and turning in those with MS. METHODS: Twelve participants with MS and eleven age- and gender-matched healthy controls participated in a cross-sectional study. All participants completed five trials of continuous walking with turns wearing weighted vests at 0%, 2%, 4%, 5%, and then 0% of their body weight. Gait parameters were measured using wireless inertial sensors. A 2 (group) x 5 (vest weight) multivariate analysis of variance (MANOVA) was performed to determine any significant differences between groups and across weighted vests for each gait variable. Post-hoc analysis and paired t-tests with corresponding effect sizes were also conducted. RESULTS: A significant between groups main effect was found for group (F (6100) = 14.74, p = .000) in multiple gait parameters (p < 0.05), although no significant main effect was found for weighted vest. Within group analyses indicated significantly increased cadence and gait speed across varying weighted vests for both MS and control groups (p < 0 >05). Increased vest weight from 0%PRE to 2% also had large effect on shortening double support time and increasing stride length in the MS group. SIGNIFICANCE: This study provided preliminary evidence that non-specific axial loads of varying weights appear to improve certain gait parameters. As such, this modality may offer mobility benefit and serve as an accessible home-based intervention alternative aimed at improving walking in individuals with MS.

The Inventory of Physical Activity Barriers for Adults 50 Years and Older: Refinement and Validation.

BACKGROUND AND OBJECTIVES: Due to health consequences associated with insufficient physical activity (PA), particularly among aging adults, health care providers should assess and address lack of PA participation. Addressing lack of PA means developing individualized PA prescriptions that incorporate solutions to PA participation barriers. Assessing PA participation barriers can be done through the Social Ecological Model-based Inventory of Physical Activity Barriers Scale (IPAB). This study aimed to refine the initial 40-item IPAB and determine its reliability and validity. RESEARCH DESIGN AND METHODS: Five hundred and three community-dwelling adults 50 years and older completed a demographic and health questionnaire, the Physical Activity Vital Sign, the IPAB, and a feedback questionnaire. For scale refinement, half of the data were used for exploratory factor analysis and the other half for confirmatory factor analysis. The refined scale underwent reliability and validity assessment, including internal consistency, test-retest reliability, and construct validity. RESULTS: The refined scale contains 27 items consisting of 7 factors and 1 stand-alone item: (a) environmental, (b) physical health, (c) PA-related motivation, (d) emotional health, (e) time, (f) skills, (g) social, and (h) energy (a stand-alone item). The 27-item IPAB has good internal consistency (alpha = 0.91) and high test-retest reliability (intraclass correlation coefficient = 0.99). The IPAB's mean scores were statistically different between those who met the recommended levels of PA and those who did not (p < .001). DISCUSSION AND IMPLICATIONS: The information gathered through the IPAB can guide discussions related to PA participation barriers and develop individualized PA prescriptions that incorporate solutions to the identified barriers.

Evaluation of Electronic and Pen-and-Paper Formats of the Inventory of Physical Activity Barriers: A Randomized Crossover Study.

BACKGROUND: The Inventory of Physical Activity Barriers (IPAB) assesses physical activity participation barriers. Development, refinement, and psychometric evaluation of the IPAB occurred via an electronic format. However, various circumstances may require using a pen-and-paper format. As instrument formats are not always interchangeable, the authors aimed to establish whether 2 different formats (electronic and pen and paper) can be used interchangeably for the IPAB. METHODS: This randomized crossover study included 66 community-dwelling adults aged 50 years and older (mean age = 73 [SD = 7.6]). Half the sample completed the electronic format of the IPAB first and the pen-and-paper format second, and the other half completed them in reverse order. Tests of equivalence and a Bland-Altman plot were performed. RESULTS: The intraclass correlation coefficient between formats was .94, and kappa was .68. The mean difference between the 2 administration forms of the IPAB was 0.002 (P = .96). Both administration formats had high internal consistency (Cronbach alpha = .92 and .93) and illustrated construct validity (P ≤ .001 for both administration formats). CONCLUSION: Pen-and-paper and electronic formats of the IPAB are equivalent and, thus, can be used interchangeably among non-Hispanic whites who are highly educated. The format should be used consistently if completing preintervention and postintervention evaluations or comparing scores.

An intensive intervention for improving gait, balance, and mobility in individuals with chronic incomplete spinal cord injury: a pilot study of activity tolerance and benefits.

OBJECTIVE: To determine the tolerance to and benefits of an intensive mobility training (IMT) approach for individuals with incomplete spinal cord injury (ISCI). DESIGN: Prospective pretest-posttest study with 6-month follow-up. SETTING: University research laboratory. PARTICIPANTS: A volunteer sample of individuals with ISCI (N=15; >6 mo postinjury and able to walk at least 3.05 m with or without assistance). Follow-up data were collected for 10 of the participants. INTERVENTIONS: Participants received IMT for 3h/d for 10 weekdays, participating in activities that encouraged repetitive, task-specific training of their lower extremities in a massed practice schedule. MAIN OUTCOME MEASURES: Amount of time spent in therapeutic activities and rest was used to assess participants' tolerance to the intervention. Treatment outcomes were assessed pretest, posttest, and 6 months after the intervention and included the Berg Balance Scale (BBS), Dynamic Gait Index (DGI), 6-minute walk test, gait speed, and Spinal Cord Injury Functional Ambulation Inventory. RESULTS: Individuals in the higher functioning ISCI group (BBS score ≥45 and gait speed ≥0.6 m/s) spent more time in the intensive therapy on average than individuals in the lower functioning ISCI group. Effect sizes were comparable for changes in balance and mobility assessments between the lower and higher functioning groups, with the largest effect sizes observed for the DGI. CONCLUSIONS: This dosage of IMT may be a more appropriate treatment approach for higher functioning ISCI individuals, as they were better able to tolerate the length of the session and demonstrated higher effect sizes postintervention.

Time-integrated propulsive and braking impulses do not depend on walking speed.

BACKGROUND: Enhancing propulsion during walking is often a focus in physical therapy for those with impaired gait. However, there is no consensus in the literature for assessing braking and propulsion. Both are typically measured from the anterior-posterior ground reaction force (AP-GRF). While normalization of AP-GRF force by bodyweight is commonly done in the analysis, different methods for AP-GRF time axis normalization are used. RESEARCH QUESTION: Does walking speed affect propulsion and/or braking, and how do different methods for calculating propulsion and braking impact the conclusion, in both healthy adults and those with lower limb impairment? METHODS: We investigated three different analysis methods for assessing propulsion. 1. BW-TimeIntegration: Bodyweight (BW) normalized time integration of AP-GRF (units of BWs). 2. BW-%StanceIntegration: BW normalized AP-GRF is resampled to percent stance phase prior to integration (units of BW%Stance). 3. BW-Peak: BW normalized peak force (units of BW). We applied these methods to two data sets. One data set included AP-GRFs from trials of slow, self-selected, and fast walking speeds for 203 healthy controls (HCs); a second data set included subjects with lower limb orthopedic injuries. RESULTS: Using the BW-TimeIntegration method, we found no effect of walking speed on propulsion for HCs. Time integration over the longer stance phase of slower walking balanced the lower magnitude AP-GRFs of slower walking, resulting in a time-integrated impulse that was the same regardless of walking speed. In contrast, the other two methods that are not time integration methods found that propulsion increased with walking speed. Similarly, in the gait pathology data set, differences in results were found depending on the analysis method used. SIGNIFICANCE: For many gait studies concerning propulsion and/or braking, the impulse measure used should be related to the body's change of momentum, necessitating an analysis method with a time integration of the AP-GRF.

Upper and Lower Limb Motor Function Correlates with Ipsilesional Corticospinal Tract and Red Nucleus Structural Integrity in Chronic Stroke: A Cross-Sectional, ROI-Based MRI Study.

BACKGROUND: Structural integrity of the ipsilesional corticospinal tract (CST) is important for upper limb motor recovery after stroke. However, additional neuromechanisms associated with motor function poststroke are less well understood, especially regarding the lower limb. OBJECTIVE: To investigate the neural basis of upper/lower limb motor deficits poststroke by correlating measures of motor function with diffusion tensor imaging-derived indices of white matter integrity (fractional anisotropy (FA), mean diffusivity (MD)) in primary and secondary motor tracts/structures. METHODS: Forty-three individuals with chronic stroke (time poststroke, 64.4 ± 58.8 months) underwent a comprehensive motor assessment and MRI scanning. Correlation and multiple regression analyses were performed to examine relationships between FA/MD in a priori motor tracts/structures and motor function. RESULTS: FA in the ipsilesional CST and red nucleus (RN) was positively correlated with motor function of both the affected upper and lower limb (r = 0.36-0.55, p ≤ 0.01), while only ipsilesional RN FA was associated with gait speed (r = 0.50). Ipsilesional CST FA explained 37.3% of the variance in grip strength (p < 0.001) and 31.5% of the variance in Arm Motricity Index (p = 0.004). Measures of MD were not predictors of motor performance. CONCLUSIONS: Microstructural integrity of the ipsilesional CST is associated with both upper and lower limb motor function poststroke, but appears less important for gait speed. Integrity of the ipsilesional RN was also associated with motor performance, suggesting increased contributions from secondary motor areas may play a role in supporting chronic motor function and could become a target for interventions.

Bathroom Modifications, Clutter, and Tripping Hazards: Prevalence and Changes after Incident Falls in Community-Dwelling Older Adults.

Objectives: To describe the prevalence of bathroom modifications, clutter, and tripping hazards in the homes of US older adults and to examine changes after an incident fall. Methods: We used data from the 2015-2017 National Health and Aging Trends Study (n = 7499). Outcomes were the prevalence of bathroom modifications, clutter, and tripping hazards and changes after incident fall. Results: In 2015, 26.5% of community-dwelling older adults had clutter or tripping hazards in the home, and 69.3% had at least one bathroom modification. Compared to nonfallers, older adults with multiple falls were significantly more likely to modify the bathroom. The magnitude of hazard reduction was similar after multiple falls but was not statistically significant. Discussion: Bathroom modifications are common and increase after multiple falls. A single incident fall does not appear to lead to home environment changes to reduce fall risk. Targeting home hazards may be an opportunity to reduce fall risk.

Differential deficits in spatial and temporal interlimb coordination during walking in persons with incomplete spinal cord injury.

BACKGROUND: Returning to community walking remains a major challenge for persons with incomplete spinal cord injury (iSCI) due, in part, to impaired interlimb coordination. Here, we examined spatial and temporal features of interlimb coordination during walking and their associations to gait deficits in persons with chronic iSCI. RESEARCH QUESTION: Do deficits in spatial and temporal interlimb coordination correspond differentially to clinical indicators of walking performance in persons with iSCI? METHODS: Sixteen persons with chronic iSCI and eleven able-bodied individuals participated in this study. Participants walked at self-selected gait speeds along an instrumented walkway that recorded left and right step lengths and times. We quantified interlimb coordination in terms of normalized differences between left and right step lengths (spatial asymmetry index) and step times (temporal asymmetry index), as well as, gap and phase coordination indices. We then assessed the extent to which these indices independently associated with clinical measures of walking performance. RESULTS: Participants with iSCI demonstrated greater spatial and temporal asymmetry, as well as, reduced gap and phase interlimb coordination as compared to age-matched controls (p < 0.001). We found no linear relationships between spatial and temporal asymmetry indices (p > 0.05) or between gap and phase coordination indices (p > 0.05). Spatial and temporal asymmetry indices weakly correlated with SCI-FAI composite scores (r2 = 0.26; p = 0.04). However, only spatial asymmetry indices strongly correlated with slower walking speed (r2 = 0.51; p < 0.002). We also found participants who used a hand-held assistive device (walker) demonstrated great spatial asymmetry as compared to those who did not (p < 0.03). SIGNIFICANCE: Differential impairments in spatial and temporal interlimb coordination correspond to overground walking deficits in persons with chronic iSCI. Spatial asymmetry associated with decreased walking speed and increased reliance on hand-held assistive devices. Gait training methods that target well-defined space and time domains of interlimb coordination may enhance overground gait training in persons with iSCI.

Constraints on Stance-Phase Force Production during Overground Walking in Persons with Chronic Incomplete Spinal Cord Injury.

Persons with incomplete spinal cord injury (iSCI) face ongoing struggles with walking, including reduced speed and increased reliance on assistive devices (ADs). The forces underlying body weight support and gait, as measured by ground reaction forces (GRFs), are likely altered after iSCI because of weakness and AD dependence but have not been studied. The purpose of this study was to examine GRF production during overground walking after iSCI, because greater insight into GRF constraints is important for refining therapeutic interventions. Because of reduced and discoordinated motor output after iSCI, we hypothesized that persons with iSCI would exert smaller GRFs and altered GRF modifications to increased cadence compared with able-bodied (AB) persons, especially when using an AD. Fifteen persons with chronic iSCI, stratified into no AD (n = 7) and AD (n = 8) groups, walked across an instrumented walkway at self-selected and fast (115% self-selected) cadences. Fifteen age-matched AB controls walked at their own cadences and iSCI-matched conditions (cadence and AD). Results showed fore-aft GRFs are reduced in persons with iSCI compared with AB controls, with reductions greatest in persons dependent on an AD. When controlling for cadence and AD, propulsive forces were still lower in persons with iSCI. Compared with AB controls, persons with iSCI demonstrated altered GRF modifications to increased cadence. Persons with iSCI exhibit different stance-phase forces compared with AB controls, which are impacted further by AD use and slower walking speed. Minimizing AD use and/or providing propulsive biofeedback during walking could enhance GRF production after iSCI.