Speed- and Endurance-Based Classifications of Community Ambulation Post-Stroke Revisited: The Importance of Location in Walking Performance Measurement.

BACKGROUND: Gait speed or 6-minute walk test are frequently used to project community ambulation abilities post-stroke by categorizing individuals as household ambulators, limited, or unlimited community ambulators. However, whether improved clinically-assessed gait outcomes truly translate into enhanced real-world community ambulation remains uncertain. OBJECTIVE: This cross-sectional study aimed to examine differences in home and community ambulation between established categories of speed- and endurance-based classification systems of community ambulation post-stroke and compare these with healthy controls. METHODS: Sixty stroke survivors and 18 healthy controls participated. Stroke survivors were categorized into low-speed, medium-speed, or high-speed groups based on speed-based classifications and into low-endurance, medium-endurance, or high-endurance groups based on the endurance-based classification. Home and community steps/day were quantified using Global Positioning System and accelerometer devices over 7 days. RESULTS: The low-speed groups exhibited fewer home and community steps/day than their medium- and high-speed counterparts (P < .05). The low-endurance group took fewer community steps/day than the high-endurance group (P < .05). Despite vast differences in clinical measures of gait speed and endurance, the medium-speed/endurance groups did not differ in their home and community steps/day from the high-speed/endurance groups, respectively. Stroke survivors took 48% fewer home steps/day and 77% fewer community steps/day than healthy controls. CONCLUSIONS: Clinical classification systems may only distinguish home ambulators from community ambulators, but not between levels of community ambulation, especially beyond certain thresholds of gait speed and endurance. Clinicians should use caution when predicting community ambulation status through clinical measures, due to the limited translation of these classification systems into the real world.

Sympathetic nervous system responses during complex walking tasks and community ambulation post-stroke.

Stroke survivors frequently report increased perceived challenge of walking (PCW) in complex environments, restricting their daily ambulation. PCW is conventionally measured through subjective questionnaires or, more recently, through objective quantification of sympathetic nervous system activity during walking tasks. However, how these measurements of PCW reflect daily walking activity post-stroke is unknown. We aimed to compare the subjective and objective assessments of PCW in predicting home and community ambulation. In 29 participants post-stroke, we measured PCW subjectively with the Activities-specific Balance Confidence (ABC) Scale and objectively through electrodermal activity, quantified by change in skin conductance levels (SCL) and skin conductance responses (SCR) between outdoor-complex and indoor-steady-state walking. High-PCW participants were categorized into high-change SCL (ΔSCL ≥ 1.7 µs), high-change SCR (ΔSCR ≥ 0.2 µs) and low ABC (ABC < 72%) groups, while low-PCW participants were categorized into low-change SCL (ΔSCL < 1.7 µs), low-change SCR (ΔSCR < 0.2 µs) and high-ABC (ABC ≥ 72%) groups. Number and location of daily steps were quantified with accelerometry and Global Positioning System devices. Compared to low-change SCL group, the high-change SCL group took fewer steps in home and community (p = 0.04). Neither ABC nor SCR groups differed in home or community steps/day. Objective measurement of PCW via electrodermal sensing more accurately represents home and community ambulation compared to the subjective questionnaire.

The influence of backward versus forward locomotor training on gait speed and balance control post-stroke: Recovery or compensation?

Backward walking training has been reported to improve gait speed and balance post-stroke. However, it is not known if gains are achieved through recovery of the paretic limb or compensations from the nonparetic limb. The purpose of this study was to compare the influence of backward locomotor training (BLT) versus forward locomotor training (FLT) on gait speed and dynamic balance control, and to quantify the underlying mechanisms used to achieve any gains. Eighteen participants post chronic stroke were randomly assigned to receive 18 sessions of either FLT (n = 8) or BLT (n = 10). Pre- and post-intervention outcomes included gait speed (10-meter Walk Test) and forward propulsion (time integral of anterior-posterior ground-reaction-forces during late stance for each limb). Dynamic balance control was assessed using clinical (Functional Gait Assessment) and biomechanical (peak-to-peak range of whole-body angular-momentum in the frontal plane) measures. Balance confidence was assessed using the Activities-Specific Balance Confidence scale. While gait speed and balance confidence improved significantly within the BLT group, these improvements were associated with an increased nonparetic limb propulsion generation, suggesting use of compensatory mechanisms. Although there were no improvements in gait speed within the FLT group, paretic limb propulsion generation significantly improved post-FLT, suggesting recovery of the paretic limb. Neither training group improved in dynamic balance control, implying the need of balance specific training along with locomotor training to improve balance control post-stroke. Despite the within-group differences, there were no significant differences between the FLT and BLT groups in the achieved gains in any of the outcomes.

Essential Competencies in Entry-Level Neurologic Physical Therapist Education.

BACKGROUND AND PURPOSE: The Academy of Neurologic Physical Therapy's (ANPT) 2021 Strategic Plan identified development of core competencies for neurologic physical therapy as a priority. The Curricular Competencies Task Force was appointed to establish competencies for entry-level neurologic physical therapist (PT) education to facilitate the delivery of current and consistent content across educational programs. SUMMARY OF KEY POINTS: A sequential exploratory process was used. First, the task force chairs, utilizing an established conceptual framework for competency-based education and a review of the broader literature, established competency domains to specifically apply to neurologic PT practice. Second, Nominal Group Technique (NGT), a structured method for small group discussion to reach consensus, was adopted. Nominal Group Technique meetings focused on developing specific competencies within each domain of neurologic PT practice by the full task force. After competencies were identified through the NGT process, the task force chairs reviewed and refined the competencies to ensure they represented distinct and specific knowledge, skill, and/or attitude within neurologic PT practice. The domains and competencies were then submitted to ANPT membership via survey for review. Member comments were qualitatively analyzed, with edits made to the competencies prior to submission to ANPT Board of Directors for approval. RECOMMENDATIONS FOR ENTRYLEVEL PT NEUROLOGIC EDUCATION: Seven essential domains were identified: participation, communication and collaboration, health promotion and wellness, movement science, assistive technology and equipment, evidence-based practice, and provider health and wellness. Essential competencies operationalize each domain. Competencies are not prescriptive but provide guidance, allowing educators to determine how to best incorporate into their curricula.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A427 ).

Recovery of walking in nonambulatory children with chronic spinal cord injuries: Case series.

The immature central nervous system is recognized as having substantial neuroplastic capacity. In this study, we explored the hypothesis that rehabilitation can exploit that potential and elicit reciprocal walking in nonambulatory children with chronic, severe (i.e., lower extremity motor score < 10/50) spinal cord injuries (SCIs). Seven male subjects (3-12 years of age) who were at least 1-year post-SCI and incapable of discrete leg movements believed to be required for walking, enrolled in activity-based locomotor training (ABLT; clinicaltrials.gov NCT00488280). Six children completed the study. Following a minimum of 49 sessions of ABLT, three of the six children achieved walking with reverse rolling walkers. Stepping development, however, was not accompanied by improvement in discrete leg movements as underscored by the persistence of synergistic movements and little change in lower extremity motor scores. Interestingly, acoustic startle responses exhibited by the three responding children suggested preserved reticulospinal inputs to circuitry below the level of injury capable of mediating leg movements. On the other hand, no indication of corticospinal integrity was obtained with transcranial magnetic stimulation evoked responses in the same individuals. These findings suggest some children who are not predicted to improve motor and locomotor function may have a reserve of adaptive plasticity that can emerge in response to rehabilitative strategies such as ABLT. Further studies are warranted to determine whether a critical need exists to re-examine rehabilitation approaches for pediatric SCI with poor prognosis for any ambulatory recovery.

Effects of Prefrontal Transcranial Direct Current Stimulation on Retention of Performance Gains on an Obstacle Negotiation Task in Older Adults.

OBJECTIVES: Complex walking in older adults can be improved with task practice and might be further enhanced by pairing transcranial direct current stimulation (tDCS) to the dorsolateral prefrontal cortex. We tested the hypothesis that a single session of practice of a complex obstacle negotiation task paired with active tDCS in older adults would produce greater within-session improvements in walking performance and retention of gains, compared to sham tDCS and no tDCS conditions. MATERIALS AND METHODS: A total of 50 older adults (mean age = 74.46 years ± 6.49) with self-reported walking difficulty were randomized to receive either active tDCS (active-tDCS group) or sham tDCS (sham-tDCS group) bilaterally to the dorsolateral prefrontal cortex or no tDCS (no-tDCS group). Each group performed ten practice trials of an obstacle negotiation task at their fastest safe speed. Retention of gains in walking performance was assessed with three trials conducted one week later. Within-session effects of practice and between-session retention effects on obstacle negotiation speed were examined. RESULTS: At the practice session, all three groups exhibited significant within-session gains in walking speed (p ≤ 0.005). However, the gains were significantly greater in the sham-tDCS group than in the active-tDCS and no-tDCS groups (p ≤ 0.03) and were comparable between the active-tDCS and no-tDCS groups (p = 0.89). At one-week follow-up, the active-tDCS group exhibited significant between-session retention of gains and continued "offline" improvement in walking speed (p = 0.005). The active-tDCS group showed significantly greater retention of gains than the no-tDCS (p = 0.02) but not the sham-tDCS group (p = 0.24). CONCLUSIONS: Pairing prefrontal active tDCS with a single session of obstacle negotiation practice may enhance one-week retention of gains in walking performance compared to no tDCS. However, the evidence is insufficient to suggest a benefit of active tDCS over sham tDCS for enhancing the gains in walking performance. Additional studies with a multisession intervention design and larger sample size are needed to further investigate these findings. CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number for the study is NCT03122236.

The 3-Meter Backward Walk Test (3MBWT): Reliability and validity in individuals with subacute and chronic stroke.

INTRODUCTION: Backward walking (BW) is an important gait adaptation and BW speed may be an important indicator of walking function and fall risk. However, the measurement characteristics of a standardized assessment of BW post-stroke have not been fully established. OBJECTIVES: To determine intra- and interrater reliability, concurrent validity and minimal detectable change (MDC) scores for the 3-Meter Backward Walk Test (3MBWT) post-stroke. METHODS: Thirty-four individuals with subacute and 29 individuals with chronic stroke participated. Two trials of comfortable BW was measured over a total distance of 5-meters, while speed was calculated during the middle 3-meters of the walking distance. Intra and interrater reliability were determined by comparing the two trials from one rater and simultaneous assessment of two raters, respectively. Two additional trials were performed and BW speed was calculated using 3MBWT and an instrumented walkway to determine concurrent validity. Intraclass correlation coefficients (ICC) estimated reliability and validity. The MDC was calculated from the standard error of measurement. RESULTS: Excellent ICC values were obtained for the 3MBWT in the subacute (interrater: ICC2,1 = 0.99; intrarater: ICC2,1 = 0.96; validity: ICC2,1 = 0.96) and chronic (interrater: ICC2,1 = 0.99; intrarater: ICC2,1 = 0.94; validity: ICC2,1 = 0.97) groups. The MDC was 0.07 m/s (subacute) and 0.11 m/s (chronic). CONCLUSIONS: Establishment of the 3MBWT as a reliable and valid measure in assessing BW speed is an important addition to the assessment toolbox for rehabilitation post-stroke.

Spatiotemporal strategies adopted to walk at fast speed in high- and low-functioning individuals post-stroke: a cross-sectional study.

BACKGROUND: Walking at fast speed is a gait training strategy post-stroke. It is unknown how faster-than-preferred pace impacts spatiotemporal gait characteristics in survivors with different functional abilities. OBJECTIVE: To test the hypothesis that compared to high-functioning individuals, low-functioning individuals will be limited in modifying spatiotemporal gait parameters for walking at faster-than-preferred speed, and these limitations are associated with fear of falling. METHODS: Forty-two adults, 17.6 ± 14.6 months post-stroke, traversed an instrumented walkway at preferred and fast speeds. Participants were categorized to a low-functioning group (LFG) (n = 20; <0.45 m/s) and high-functioning group (HFG) (n = 22; ≥0.45 m/s). Cadence, step length, stance time and spatiotemporal asymmetry measures were calculated. The Modified Falls-efficacy Scale examined fear of falling. Multivariate and correlational analysis tested hypotheses. RESULTS: Increased speed from preferred to fast pace was significantly greater for HFG (0.27 ± 0.03 m/s) than LFG (0.10 ± 0.02 m/s) (p ≤ 0.001). Cadence gain from preferred to fast pace did not differ between groups. However, HFG exhibited greater change in paretic (∆6.1 ± 1.37 cm; p < .001) and non-paretic step lengths (∆4.5 ± 1.37 cm; p = .003) than LFG. Spatiotemporal asymmetry did not change for either group. Fear of falling had moderately positive correlation with ∆paretic step length (r = 0.43; p = .004) and ∆non-paretic step length (r = 0.32; p = .035). CONCLUSIONS: While both low- and high-functioning individuals used a step-lengthening strategy to walk at faster-than-preferred speeds, the gain in step lengths was limited in low-functioning individuals and was partially explained by falls-efficacy.

Somatosensory impairment of the feet is associated with higher activation of prefrontal cortex during walking in older adults.

BACKGROUND: Over-activation of prefrontal cortex during walking has been reported in older adults versus young adults. Heighted activity in prefrontal cortex suggests a shift toward an executive control strategy to control walking. A potential contributing factor is degraded functioning of pattern-generating locomotor circuits in the central nervous system that are important to walking coordination. Somatosensory information is a crucial input to these circuits, so age-related impairment of somatosensation would be expected to compromise the neural control of walking. The present study tested the hypothesis that poorer somatosensation in the feet of older adults will be associated with greater recruitment of the prefrontal cortex during walking. This study also examines the extent to which somatosensory function and prefrontal activity are associated with performance on walking and balance assessments. METHODS: Forty seven older adults (age 74.6 ± 6.8 years; 32 female) participated in walking assessments (typical walking and obstacle negotiation) and Berg Balance Test. During walking, prefrontal activity was measured with functional near infrared spectroscopy (fNIRS). Participants also underwent somatosensory testing with Semmes-Weinstein monofilaments. RESULTS: The primary findings is that worse somatosensory monofilament level was associated with greater prefrontal cortical activity during typical walking (r = 0.38, p = 0.008) and obstacle negotiation (r = 0.40, p = 0.006). For the obstacle negotiation task, greater prefrontal activity was associated with faster walking speed (p = 0.004). Poorer somatosensation was associated with slower typical walking speed (p = 0.07) and obstacles walking speed (p < 0.001), as well as poorer balance scores (p = 0.03). CONCLUSIONS: The study findings are consistent with a compensation strategy of recruiting prefrontal/executive control resources to overcome loss of somatosensory input to the central nervous system. Future research should further establish the mechanisms by which somatosensory impairments are linked to the neural control and performance of walking tasks, as well as develop intervention approaches.

Benefits of an interdisciplinary stroke clinic: addressing a gap in physical therapy at post-stroke neurology follow-up.

BACKGROUND AND PURPOSE: An interdisciplinary stroke clinic (ISC) can improve communication and identify people post-stroke who have not reached their full recovery potential. We describe the characteristics of participants who underwent physical therapy (PT) evaluation in addition to their outpatient neurology evaluation and identify the association of assessment scales that predicted referral for additional rehabilitation. METHODS: Participants' post-stroke seen in the ISC were included in the study. The PT evaluation included the Berg Balance Scale (BBS), Ten-Meter Walk Test (10MWT), Six-Minute Walk Test (6MWT), and Short Form-Stroke Impact Scale (SF-SIS). Multivariable logistic regression analysis was performed to identify factors associated with referral for additional rehabilitation. RESULTS: The study consisted of 148 participants with a mean age of 63 (SD ± 15) years; 58% were women and 76% were Whites. Additional rehabilitation was recommended for 59% of participants. In multivariate analysis, reduced speed on comfortable 10MWT (OR = 0.06; 95%CI = 0.01-0.51) and lower SF-SIS score (OR = 0.76; 95%CI = 0.66-0.87) were significantly associated with referral for additional PT or occupational therapy. CONCLUSION: A significant number of post-acute stroke survivors were found to be appropriate for additional rehabilitation when assessed clinically by a neurologic physical therapist in an ISC. The measures that most closely correlated with this in-person clinical evaluation were 10MWT and SF-SIS.IMPLICATIONS FOR REHABILITATIONAn interdisciplinary stroke clinic can improve communication and identify people post-stroke who have not reached their full recovery potential.In a pilot study, a significant number of post-acute stroke survivors were found to be appropriate for additional rehabilitation when assessed clinically by a neurologic physical therapist in an interdisciplinary stroke clinic.Reduced speed on comfortable Ten-Meter Walk Test and lower Short Form-Stroke Impact Scale scores were associated with referral for additional rehabilitation.

Trajectories of stroke recovery of impairment, function, and quality of life in response to 12-month mobility and fitness intervention.

BACKGROUND: Gait deficits and functional disability are persistent problems for many stroke survivors, even after standard neurorehabilitation. There is little quantified information regarding the trajectories of response to a long-dose, 12-month intervention. OBJECTIVE: We quantified treatment response to an intensive neurorehabilitation mobility and fitness program. METHODS: The 12-month neurorehabilitation program targeted impairments in balance, limb coordination, gait coordination, and functional mobility, for five chronic stroke survivors. We obtained measures of those variables every two months. RESULTS: We found statistically and clinically significant group improvement in measures of impairment and function. There was high variation across individuals in terms of the timing and the gains exhibited. CONCLUSIONS: Long-duration neurorehabilitation (12 months) for mobility/fitness produced clinically and/or statistically significant gains in impairment and function. There was unique pattern of change for each individual. Gains exhibited late in the treatment support a 12-month intervention. Some measures for some subjects did not reach a plateau at 12 months, justifying further investigation of a longer program (>12 months) of rehabilitation and/or maintenance care for stroke survivors.

Rehabilitation with accurate adaptability walking tasks or steady state walking: A randomized clinical trial in adults post-stroke.

OBJECTIVE: To assess changes in walking function and walking-related prefrontal cortical activity following two post-stroke rehabilitation interventions: an accurate adaptability (ACC) walking intervention and a steady state (SS) walking intervention. DESIGN: Randomized, single blind, parallel group clinical trial. SETTING: Hospital research setting. SUBJECTS: Adults with chronic post-stroke hemiparesis and walking deficits. INTERVENTIONS: ACC emphasized stepping accuracy and walking adaptability, while SS emphasized steady state, symmetrical stepping. Both included 36 sessions led by a licensed physical therapist. ACC walking tasks recruit cortical regions that increase corticospinal tract activation, while SS walking activates the corticospinal tract less intensely. MAIN MEASURES: The primary functional outcome measure was preferred steady state walking speed. Prefrontal brain activity during walking was measured with functional near infrared spectroscopy to assess executive control demands. Assessments were conducted at baseline, post-intervention (three months), and follow-up (six months). RESULTS: Thirty-eight participants were randomized to the study interventions (mean age 59.6 ± 9.1 years; mean months post-stroke 18.0 ± 10.5). Preferred walking speed increased from baseline to post-intervention by 0.13 ± 0.11 m/s in the ACC group and by 0.14 ± 0.13 m/s in the SS group. The Time × Group interaction was not statistically significant (P = 0.86). Prefrontal fNIRS during walking decreased from baseline to post-intervention, with a marginally larger effect in the ACC group (P = 0.05). CONCLUSIONS: The ACC and SS interventions produced similar changes in walking function. fNIRS suggested a potential benefit of ACC training for reducing demand on prefrontal (executive) resources during walking.

Does Falls Efficacy Influence the Relationship Between Forward and Backward Walking Speed After Stroke?

OBJECTIVE: Forward walking speed (FWS) is known to be an important predictor of mobility, falls, and falls-related efficacy poststroke. However, backward walking speed (BWS) is emerging as an assessment tool to reveal mobility deficits in people poststroke that may not be apparent with FWS alone. Since backward walking is more challenging than forward walking, falls efficacy may play a role in the relationship between one's preferred FWS and BWS. We tested the hypothesis that people with lower falls efficacy would have a stronger positive relationship between FWS and BWS than those with higher falls efficacy. METHODS: Forty-five individuals (12.9 ± 5.6 months poststroke) participated in this observational study. We assessed FWS with the 10-meter walk test and BWS with the 3-meter backward walk test. The modified Falls-Efficacy Scale (mFES) quantified falls efficacy. A moderated regression analysis examined the hypothesis. RESULTS: FWS was positively associated with BWS (R2 = 0.26). The addition of the interaction term FWS × mFES explained 7.6% additional variance in BWS. As hypothesized, analysis of the interaction revealed that people with lower falls efficacy (mFES ≤ 6.6) had a significantly positive relationship between their preferred FWS and BWS, whereas people with higher falls efficacy (mFES > 6.6) had no relationship between their walking speed in the 2 directions. CONCLUSIONS: FWS is positively related to BWS poststroke, but this relationship is influenced by one's perceived falls efficacy. Our results suggest that BWS can be predicted from FWS in people with lower falls efficacy, but as falls efficacy increases, BWS becomes a separate and unassociated construct from FWS. IMPACT: This study provides unique evidence that the degree of falls efficacy significantly influences the relationship between FWS and BWS poststroke. Physical therapists should examine both FWS and BWS in people with higher falls efficacy, but further investigation is warranted for those with lower falls efficacy.

Combining Frontal Transcranial Direct Current Stimulation With Walking Rehabilitation to Enhance Mobility and Executive Function: A Pilot Clinical Trial.

OBJECTIVES: This pilot study assessed whether frontal lobe transcranial direct current stimulation (tDCS) combined with complex walking rehabilitation is feasible, safe, and shows preliminary efficacy for improving walking and executive function. MATERIALS AND METHODS: Participants were randomized to one of the following 18-session interventions: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Active tDCS was delivered over F3 (cathode) and F4 (anode) scalp locations for 20 min at 2 mA intensity. Outcome measures included tests of walking function, executive function, and prefrontal activity measured by functional near infrared spectroscopy. RESULTS: Ninety percent of participants completed the intervention protocol successfully. tDCS side effects of tingling or burning sensations were low (average rating less than two out of 10). All groups demonstrated gains in walking performance based on within-group effect sizes (d ≥ 0.50) for one or more assessments. The Sham/Typical group showed the greatest gains for walking based on between-group effect sizes. For executive function, the Active/Complex group showed the greatest gains based on moderate to large between-group effect sizes (d = 0.52-1.11). Functional near-infrared spectroscopy (fNIRS) findings suggest improved prefrontal cortical activity during walking. CONCLUSIONS: Eighteen sessions of walking rehabilitation combined with tDCS is a feasible and safe intervention for older adults. Preliminary effects size data indicate a potential improvement in executive function by adding frontal tDCS to walking rehabilitation. This study justifies future larger clinical trials to better understand the benefits of combining tDCS with walking rehabilitation.

Obstacle Negotiation in Older Adults: Prefrontal Activation Interpreted Through Conceptual Models of Brain Aging.

BACKGROUND AND OBJECTIVES: The influence of interindividual differences on brain activation during obstacle negotiation and the implications for walking performance are poorly understood in older adults. This study investigated the extent to which prefrontal recruitment during obstacle negotiation is explained by differences in age, executive function, and sex. These data were interpreted according to the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH) framework of brain aging. We also tested the association between prefrontal recruitment and walking performance. RESEARCH DESIGN AND METHODS: Prefrontal oxygenated hemoglobin concentration (O2Hb) was measured during typical walking (Typical) and obstacle negotiation (Obstacles) tasks in 50 adults aged 65 years and older using functional near-infrared spectroscopy. The primary outcome was the change in prefrontal recruitment (∆PFR), measured as Obstacles ∆O2Hb minus Typical ∆O2Hb. Multiple regression was used to test the relationship between ∆PFR and age, executive function measured by the Trail Making Test, and sex. Pearson's correlation coefficient was used to investigate the association between ∆PFR and the cost of Obstacles walking speed relative to Typical walking. RESULTS: Age, executive function, and their interaction significantly predicted greater ∆PFR (R 2 = 0.34, p = .01). Participants were subgrouped according to age and executive function to examine the interaction effects. Adults of lower age and with lower executive function exhibited greater ∆PFR during Obstacles compared to their peers with higher executive function (p = .03). Adults of advanced age exhibited a ceiling of prefrontal recruitment during obstacle negotiation, regardless of executive function level (p = .87). Greater ∆PFR was significantly associated with a smaller cost of Obstacles (r = 0.3, p = .03). DISCUSSION AND IMPLICATIONS: These findings are consistent with the CRUNCH framework: neural inefficiency where a greater amount of brain activation is needed for task performance at a similar level, compensatory overactivation to prevent a steeper decline in task performance, and capacity limitation with a recruitment ceiling effect.

Innovative Long-Dose Neurorehabilitation for Balance and Mobility in Chronic Stroke: A Preliminary Case Series.

(1) Objective: The objective was two-fold: (a) test a protocol of combined interventions; (b) administer this combined protocol within the framework of a six-month, intensive, long-duration program. The array of interventions was designed to target the treatment-resistant impairments underlying persistent mobility dysfunction: weakness, balance deficit, limb movement dyscoordination, and gait dyscoordination. (2) Methods: A convenience sample of eight chronic stroke survivors (>4 months post stroke) was enrolled. Treatment was 5 days/week, 1-2.5 h/day for 6 months, as follows: strengthening exercise, balance training, limb/gait coordination training, and aerobic exercise. Outcome measures: Berg Balance Scale (BBS), Fugl-Meyer Lower Limb Coordination (FM), gait speed, 6 Minute Walk Test (6MWT), Timed up and Go (TUG), Functional Independence Measure (FIM), Craig Handicap Assessment Rating Tool (CHART), and personal milestones. Pre-/post-treatment comparisons were conducted using the Permutation Test, suitable for ordinal measures and small sample size. (3) Results: For the group, there was a statistically (p ≤ 0.04) significant improvement in balance, limb movement coordination (FM), gait speed, functional mobility (TUG), and functional activities (FIM). There were measurable differences (minimum detectible change: MDC) in BBS, FM, gait speed, 6MWT, and TUG. There were clinically significant milestones achieved for selected subjects according to clinical benchmarks for the BBS, 6MWT, gait speed, and TUG, as well as achievement of personal milestones of life role participation. Effect sizes (Cohen's D) ranged from 0.5 to 1.0 (with the exception of the (6MWT)). After six months of treatment, the above array of gains were beyond that reported by other published studies of chronic stroke survivor interventions. Personal milestones included: walking to mailbox, gardening/yardwork, walking a distance to neighbors, return to driving, membership at a fitness center, vacation trip to the beach, swimming at local pool, returning to work, housework, cooking meals. (4) Conclusions: Stroke survivors with mobility dysfunction were able to participate in the long-duration, intensive program, with the intervention array targeted to address impairments underlying mobility dysfunction. There were either clinically or statistically significant improvements in an array of measures of impairment, functional mobility, and personal milestone achievements.

Interpreting Prefrontal Recruitment During Walking After Stroke: Influence of Individual Differences in Mobility and Cognitive Function.

Background: Functional near-infrared spectroscopy (fNIRS) is a valuable neuroimaging approach for studying cortical contributions to walking function. Recruitment of prefrontal cortex during walking has been a particular area of focus in the literature. The present study investigated whether task-related change in prefrontal recruitment measured by fNIRS is affected by individual differences in people post-stroke. The primary hypotheses were that poor mobility function would contribute to prefrontal over-recruitment during typical walking, and that poor cognitive function would contribute to a ceiling in prefrontal recruitment during dual-task walking (i.e., walking with a cognitive task). Methods: Thirty-three adults with chronic post-stroke hemiparesis performed three tasks: typical walking at preferred speed (Walk), serial-7 subtraction (Serial7), and walking combined with serial-7 subtraction (Dual-Task). Prefrontal recruitment was measured with fNIRS and quantified as the change in oxygenated hemoglobin concentration (ΔO2Hb) between resting and active periods for each task. Spatiotemporal gait parameters were measured on an electronic walkway. Stepwise regression was used to assess how prefrontal recruitment was affected by individual differences including age, sex, stroke region, injured hemisphere, stroke chronicity, 10-meter walking speed, balance confidence measured by Activities-specific Balance Confidence (ABC) Scale, sensorimotor impairment measured by Fugl-Meyer Assessment, and cognitive function measured by Mini-Mental State Examination (MMSE). Results: For Walk, poor balance confidence (ABC Scale score) significantly predicted greater prefrontal recruitment (ΔO2Hb; R 2 = 0.25, p = 0.003). For Dual-Task, poor cognitive function (MMSE score) significantly predicted lower prefrontal recruitment (ΔO2Hb; R 2 = 0.25, p = 0.002). Conclusions: Poor mobility function predicted higher prefrontal recruitment during typical walking, consistent with compensatory over-recruitment. Poor cognitive function predicted lower prefrontal recruitment during dual-task walking, consistent with a recruitment ceiling effect. These findings indicate that interpretation of prefrontal recruitment should carefully consider the characteristics of the person and demands of the task.

Clinical application of backward walking training to improve walking function, balance, and fall-risk in acute stroke: a case series.

Background: With limited inpatient rehabilitation (IR) length of stays for patients post-stroke, it is critical to maximize the effectiveness of interventions to address their balance and gait speed deficits. Backward walking (BW) is an emerging training approach; however, its application to patient populations consistent with those in IR is limited. Objectives: To describe the effects of an additional BW training program to standard IR care on balance, walking ability and fall-risk in a heterogenic caseload of adults <2 weeks post-stroke with a broad range of lesion locations and physical sequelae. Methods: Eight patients with first-time stroke (5 male; average age 66.5 ± 11.7 years; average stroke onset 7.6 ± 1.6 days; 6 right hemiparesis) participated in 10-daily sessions that included 20 min of over ground BW training for each session, in addition to standard IR. Standard outcome measures were used to assess balance, walking ability and fall-risk at admission and post-intervention. Results: All eight patients demonstrated improvements in all outcomes with a clinically meaningful increase in forward walking speed, as measured by 10MWT. Four participants exceeded fall-risk cut-off scores for all balance-related outcome measures. Conclusions: In a diverse patient population early after stroke, individuals successfully participated in an additional BW training program. Despite the patients' acuity and severe impairments in walking, significant gains in balance and walking function were noted. This program may be useful in improving outcomes with patient characteristics commonly seen in IR.

Assessment of backward walking unmasks mobility impairments in post-stroke community ambulators.

Background: While over half of stroke survivors recover the ability to walk without assistance, deficits persist in the performance of walking adaptations necessary for safe home and community mobility. One such adaptation is the ability to walk or step backward. Post-stroke rehabilitation rarely includes backward walking (BW) assessment and BW deficits have not been quantified in post-stroke community ambulators. Objective: To quantify spatiotemporal and kinematic BW characteristics in post-stroke community ambulators and compare their performance to controls. Methods: Individuals post-stroke (n = 15, 60.1 ± 12.9 years, forward speed: 1.13 ± 0.23 m/s) and healthy adults (n = 12, 61.2 ± 16.2 years, forward speed: 1.40 ± 0.13 m/s) performed forward walking (FW) and BW during a single session. Step characteristics and peak lower extremity joint angles were extracted using 3D motion analysis and analyzed with mixed-method ANOVAs (group, walking condition). Results: The stroke group demonstrated greater reductions in speed, step length and cadence and a greater increase in double-support time during BW compared to FW (p < .01). Compared to FW, the post-stroke group demonstrated greater reductions in hip extension and knee flexion during BW (p < .05). The control group demonstrated decreased plantarflexion and increased dorsiflexion during BW, but these increases were attenuated in the post-stroke group (p < .05). Conclusions: Assessment of BW can unmask post-stroke walking impairments not detected during typical FW. BW impairments may contribute to the mobility difficulties reported by adults post-stroke. Therefore, BW should be assessed when determining readiness for home and community ambulation.

A Perspective on Objective Measurement of the Perceived Challenge of Walking.

Perceived challenge of walking is a broad term that we use to encompass walking-related anxiety, balance self-efficacy/confidence, and fear of falling. Evidence shows that even after accounting for physical performance capabilities, a higher perceived challenge can cause individuals to self-impose restrictions in walking-related activities. Perceived challenge is typically measured by self-report, which is susceptible to subjective measurement bias and error. We assert that measurement of perceived challenge can be enhanced by augmenting self-report with objective, physiologically based measures. A promising approach that has emerged in the literature is measurement of sympathetic nervous system (SNS) activity by recording skin conductance. Heightened SNS activity is a physiological stress response to conditions that are cognitively, emotionally, or physically challenging. In the present article, we explain the rationale and physiological basis for measuring SNS activity to assess perceived challenge of walking. We also present existing and new evidence supporting the feasibility of this approach for assessing perceived challenge in lab-based and real-world walking environments. Future research directions are also discussed.