Consensus Paper: Ataxic Gait.

The aim of this consensus paper is to discuss the roles of the cerebellum in human gait, as well as its assessment and therapy. Cerebellar vermis is critical for postural control. The cerebellum ensures the mapping of sensory information into temporally relevant motor commands. Mental imagery of gait involves intrinsically connected fronto-parietal networks comprising the cerebellum. Muscular activities in cerebellar patients show impaired timing of discharges, affecting the patterning of the synergies subserving locomotion. Ataxia of stance/gait is amongst the first cerebellar deficits in cerebellar disorders such as degenerative ataxias and is a disabling symptom with a high risk of falls. Prolonged discharges and increased muscle coactivation may be related to compensatory mechanisms and enhanced body sway, respectively. Essential tremor is frequently associated with mild gait ataxia. There is growing evidence for an important role of the cerebellar cortex in the pathogenesis of essential tremor. In multiple sclerosis, balance and gait are affected due to cerebellar and spinal cord involvement, as a result of disseminated demyelination and neurodegeneration impairing proprioception. In orthostatic tremor, patients often show mild-to-moderate limb and gait ataxia. The tremor generator is likely located in the posterior fossa. Tandem gait is impaired in the early stages of cerebellar disorders and may be particularly useful in the evaluation of pre-ataxic stages of progressive ataxias. Impaired inter-joint coordination and enhanced variability of gait temporal and kinetic parameters can be grasped by wearable devices such as accelerometers. Kinect is a promising low cost technology to obtain reliable measurements and remote assessments of gait. Deep learning methods are being developed in order to help clinicians in the diagnosis and decision-making process. Locomotor adaptation is impaired in cerebellar patients. Coordinative training aims to improve the coordinative strategy and foot placements across strides, cerebellar patients benefiting from intense rehabilitation therapies. Robotic training is a promising approach to complement conventional rehabilitation and neuromodulation of the cerebellum. Wearable dynamic orthoses represent a potential aid to assist gait. The panel of experts agree that the understanding of the cerebellar contribution to gait control will lead to a better management of cerebellar ataxias in general and will likely contribute to use gait parameters as robust biomarkers of future clinical trials.

Perceived exertion is not a substitute for fatiguability in spinal muscular atrophy.

INTRODUCTION/AIMS: Fatiguability and perceived fatigue are common unrelated symptoms in ambulatory individuals with spinal muscular atrophy (SMA). Ratings of perceived exertion (RPE) measures the sense of effort during an activity and has been used as a proxy for fatigue. Relationships between perceived fatigue, fatiguability, and RPE have been described in healthy populations, but the relationship in SMA has not been examined. METHODS: Eighteen ambulatory individuals with SMA and 16 age-matched controls (age, 13 to 57 years; 26 [76.5%] males) performed the 6-minute walk test (6MWT) and cardiopulmonary exercise tolerance test (CPET) and completed the International Physical Activity Questionnaire---short form (IPAQ). RPE was collected during the CPET and 6MWT. Fatiguability was measured during the 6MWT. Physical activity (PA) volume was calculated using the IPAQ. Wilcoxon rank-sum tests were used to compare groups. Spearman correlation coefficients evaluated associations between variables. SMA subgroups were predetermined using 6MWT distances of over or under 300 meters. RESULTS: There were no significant associations between fatiguability and RPE or PA in SMA (P > .05). PA was strongly associated with 6MWT RPE (r = 0.71) in SMA individuals who walked fewer than 300 meters (n = 7). There were no significant associations between any variables in controls (P > .05). DISCUSSION: RPE is not associated with fatiguability in SMA. The possible association of PA and RPE may reflect the increased intensity of the 6MWT in weaker patients. RPE represents a sense of effort during exercise and should not be used as a substitute for fatiguability but may be a measure of patient experience during exercise.

Utility of the AM-PAC "6 Clicks" Basic Mobility and Daily Activity Short Forms to Determine Discharge Destination in an Acute Stroke Population.

IMPORTANCE: The American Heart Association and American Stroke Association recommend early identification of level of rehabilitative care as a priority after stroke. OBJECTIVE: To evaluate the utility of the Activity Measure for Post-Acute Care (AM-PAC) "6 Clicks" Daily Activity and Basic Mobility forms to determine the next level of rehabilitation after hospitalization for adults with stroke. DESIGN: Retrospective cohort design using medical records from 2015 to 2016. SETTING: Major urban hospital. PARTICIPANTS: Patients admitted to the stroke service, with a confirmed stroke, who were seen by a physical or occupational therapist; who had a 6 Clicks Basic Mobility or Daily Activity score at initial evaluation; and who were discharged to home, an acute inpatient rehabilitation facility (IRF), or a subacute skilled nursing facility (SNF). OUTCOMES AND MEASURES: Length of stay and discharge destination. RESULTS: Seven hundred four participants (M age = 68.28 yr; 51.21% female) were included. Analysis of variance and receiver operating characteristic curves were performed. Daily Activity scores were highest for home discharge, lower for IRF discharge, and lowest for SNF discharge; Basic Mobility showed a similar pattern. Cutoff values distinguishing home from further inpatient rehabilitation were 44.50 for Basic Mobility and 39.40 for Daily Activity scores (area under the curve [AUC] = .82 for both forms), with scores of 34.59 (AUC = 0.64) and 31.32 (AUC = 0.67) separating IRF from SNF, respectively. CONCLUSIONS AND RELEVANCE: Therapists should incorporate 6 Clicks scores into their discharge planning. What This Article Adds: This research demonstrates the utility of an outcome measure in the acute care setting that assists in planning discharge destination for patients with stroke.

Effects of Power Training on Gait, Power, and Function in Children with Cerebral Palsy.

AIMS: This scoping review aims to: 1) examine available literature regarding the effects of power training on gait speed, power, and function in ambulatory children with CP and 2) identify the variations in exercise dosage and rehabilitation recommendations for power training and plyometrics in children with CP. METHODS: Four databases (PubMed, CINAHL, Embase, and Cochrane) were searched for papers including power or plyometric training with outcome measures for gait, power or functional performance. ES was calculated for RCTs. Cohorts and case series/studies were evaluated qualitatively. RESULTS: Ten articles fit search criteria: four RCTs, three cohort studies, one case series, and two case studies. Power training consistently demonstrated improvements in muscle power compared to its effects on gait and function. ES of mean MPST (W) ranged from 0.36-1.13. 1 MWT and SSGS ES were 1.31 and 1.15, respectively. TUG ES ranged from -0.33 to -2.42. ES for GMFM-66 was 0.13 and 1.11 for Dimension D and Dimension E, respectively. CONCLUSIONS: There is limited, but promising evidence to support that power training may improve gait speed, power, and function in children with CP. Future, more robust research is required to examine effects in a larger, diverse population, to determine long-term effects and exercise prescription.

Wearable Biofeedback System to Induce Desired Walking Speed in Overground Gait Training.

Biofeedback systems have been extensively used in walking exercises for gait improvement. Past research has focused on modulating the wearer's cadence, gait variability, or symmetry, but none of the previous works has addressed the problem of inducing a desired walking speed in the wearer. In this paper, we present a new, minimally obtrusive wearable biofeedback system (WBS) that uses closed-loop vibrotactile control to elicit desired changes in the wearer's walking speed, based on the predicted user response to anticipatory and delayed feedback. The performance of the proposed control was compared to conventional open-loop rhythmic vibrotactile stimulation with N = 10 healthy individuals who were asked to complete a set of walking tasks along an oval path. The closed-loop vibrotactile control consistently demonstrated better performance than the open-loop control in inducing desired changes in the wearer's walking speed, both with constant and with time-varying target walking speeds. Neither open-loop nor closed-loop stimuli affected natural gait significantly, when the target walking speed was set to the individual's preferred walking speed. Given the importance of walking speed as a summary indicator of health and physical performance, the closed-loop vibrotactile control can pave the way for new technology-enhanced protocols for gait rehabilitation.

Randomized Trial on the Effects of Attentional Focus on Motor Training of the Upper Extremity Using Robotics With Individuals After Chronic Stroke.

OBJECTIVE: To compare the long-term effects of external focus (EF) and internal focus (IF) of attention after 4 weeks of arm training. DESIGN: Randomized, repeated-measures, mixed analysis of variance. SETTING: Outpatient clinic. PARTICIPANTS: Individuals with stroke and moderate-to-severe arm impairment living in the community (N=33; withdrawals: n=3). INTERVENTIONS: Four-week arm training protocol on a robotic device (12 sessions). MAIN OUTCOME MEASURES: Joint independence, Fugl-Meyer Assessment, and Wolf Motor Function Test measured at baseline, discharge, and 4-week follow-up. RESULTS: There were no between-group effects for attentional focus. Participants in both groups improved significantly on all outcome measures from baseline to discharge and maintained those changes at 4-week follow-up regardless of group assignment (joint independence EF condition: F1.6,45.4=17.74; P<.0005; partial η2=.39; joint independence IF condition: F2,56=18.66; P<.0005; partial η2=.40; Fugl-Meyer Assessment: F2,56=27.83; P<.0005; partial η2=.50; Wolf Motor Function Test: F2,56=14.05; P<.0005; partial η2=.35). CONCLUSIONS: There were no differences in retention of motor skills between EF and IF participants 4 weeks after arm training, suggesting that individuals with moderate-to-severe arm impairment may not experience the advantages of an EF found in healthy individuals. Attentional focus is most likely not an active ingredient for retention of trained motor skills for individuals with moderate-to-severe arm impairment, whereas dosage and intensity of practice appear to be pivotal. Future studies should investigate the long-term effects of attentional focus for individuals with mild arm impairment.

Arm swing as a potential new prodromal marker of Parkinson's disease.

BACKGROUND: Reduced arm swing is a well-known clinical feature of Parkinson's disease (PD), often observed early in the course of the disease. We hypothesized that subtle changes in arm swing and axial rotation may also be detectable in the prodromal phase. OBJECTIVE: The purpose of this study was to evaluate the relationship between the LRRK2-G2019S mutation, arm swing, and axial rotation in healthy nonmanifesting carriers and noncarriers of the G2019S mutation and in patients with PD. METHODS: A total of 380 participants (186 healthy nonmanifesting controls and 194 PD patients) from 6 clinical sites underwent gait analysis while wearing synchronized 3-axis body-fixed sensors on the lower back and bilateral wrists. Participants walked for 1 minute under the following 2 conditions: (1) usual walking and (2) dual-task walking. Arm swing amplitudes, asymmetry, variability, and smoothness were calculated for both arms along with measures of axial rotation. RESULTS: A total of 122 nonmanifesting participants and 67 PD patients were carriers of the G2019S mutation. Nonmanifesting mutation carriers walked with greater arm swing asymmetry and variability and lower axial rotation smoothness under the dual task condition when compared with noncarriers (P < .04). In the nonmanifesting mutation carriers, arm swing asymmetry was associated with gait variability under dual task (P = .003). PD carriers showed greater asymmetry and variability of movement than PD noncarriers, even after controlling for disease severity (P < .009). CONCLUSIONS: The G2019S mutation is associated with increased asymmetry and variability among nonmanifesting participants and patients with PD. Prospective studies should determine if arm swing asymmetry and axial rotation smoothness may be used as motor markers of prodromal PD. © 2016 International Parkinson and Movement Disorder Society.

Aging-related decrements during specific phases of the dual-task Timed Up-and-Go test.

BACKGROUND: It is unclear how young and older adults modulate dual-task mobility under changing postural challenges. AIM: To examine age-related changes in dual-task processing during specific phases of dual-task Timed Up-and-Go (TUGdual-task). METHOD: Healthy young and older adults performed the Timed Up-and-Go (TUG) with the following dual-task conditions: (1) serial-three subtractions, (2) carrying cup of water, (3) combined subtraction and carrying water, and (4) dialing cell phone. The primary outcome was the dual-task cost on performance of TUG (percent change from single- to dual-task) based on duration and peak trunk velocity of each phase: (a) straight-walk, (b) sit-to-stand, (c) turn, (d) turn-to-sit. Mixed-design univariate analysis of variance was performed for each type of task. RESULTS: Older adults had more pronounced mobility decrements than young adults during straight-ahead walking and turns when the secondary task engaged both cognitive and manual modalities. Simple cognitive or manual tasks during TUGdual-task did not differentiate young from older participants. Subtraction performance during simple and complex cognitive conditions differed by phase of the TUG. Manual task performance of carrying water did not vary by phase or age. DISCUSSION: Our findings suggest that dual-task processing is dynamic across phases of TUGdual-task. Aging-related dual-task decrements are demonstrated during straight-ahead walking and turning, particularly when the secondary task is more complex. CONCLUSION: Older adults are susceptible to reduced dual-task mobility during straight-ahead walking and turning particularly when attentional loading was increased.

Variability in interval production is due to timing-dependent deficits in Huntington's disease.

In Huntington's disease (HD), increased variability is seen in performance of motor tasks that require implicit control of timing. We examined whether timing variability was also evident in an explicit interval-timing task. Sixty subjects (21 controls, 19 manifest HD, and 20 pre-manifest HD) performed a single-interval production task with three target intervals (1.1 s, 2.2 s, 3.3 s). We analyzed accuracy (proportional error) and precision (standard deviation) across groups and intervals. No differences were seen in accuracy across groups or intervals. Precision was significantly lower in manifest (P = 0.0001) and pre-manifest HD (P = 0.04) compared with controls. This was particularly true for pre-manifest subjects close to diagnosis (based on probability of diagnosis in 5 years). Precision was correlated with proximity to diagnosis (r2 = 0.3, P < 0.01). To examine the source of reduced precision, we conducted linear regression of standard deviation with interval duration. Slope of the regression was significantly higher in manifest HD (P = 0.02) and in pre-manifest HD close to diagnosis (P = 0.04) compared with controls and pre-manifest participants far from diagnosis. Timing precision is impaired before clinical diagnosis in Huntington's disease. Slope analysis suggests that timing variability (decreased precision) was attributable to deficits in timing-dependent processes. Our results provide additional support for the proposal that the basal ganglia are implicated in central timekeeping functions. Because the single interval production task was sensitive to deficits in pre-manifest HD, temporal precision may be a useful outcome measure in future clinical trials.

Leg muscle function and fatigue during walking in spinal muscular atrophy type 3.

INTRODUCTION: Spinal muscular atrophy (SMA) causes muscle weakness and fatigue. Better understanding of the relationship between weakness and fatigue may help identify potential targets for rehabilitation. METHODS: Gait and surface electromyography (EMG) from 4 muscle groups were measured during the Six-Minute Walk Test (6MWT) in 10 ambulatory participants, aged 9-49 years. Average root mean square amplitude (RMS) of muscle activity was calculated. Strength was assessed using manual and quantitative methods. RESULTS: RMS, stride length, and velocity decreased during the 6MWT. Knee flexor and hip abductor strength was associated with fatigue-related changes; overall strength correlated with disease duration; and leg strength was associated with 6MWT distance. CONCLUSIONS: Clinical measures are valid in assessing fatigue and function in SMA, and these assessments can be enhanced by use of gait analysis and EMG. Disease duration and strength measures may represent further stratification refinements when enrolling patients in clinical trials.

Balance confidence and falls in nondemented essential tremor patients: the role of cognition.

OBJECTIVES: To examine (1) the effect of cognitive ability on balance confidence and falls, (2) the relationship of balance confidence and falls with quantitative measures of gait, and (3) measures that predict falls, in people with essential tremor (ET). DESIGN: Cross-sectional study. SETTING: General community. PARTICIPANTS: People with ET (n=132) and control subjects (n=48). People with ET were divided into 2 groups based on the median score on the Modified Mini-Mental State Examination: those with lower cognitive test scores (ET-LCS) and those with higher cognitive test scores (ET-HCS). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Six-item Activities of Balance Confidence (ABC-6) Scale and falls in the previous year. RESULTS: Participants with ET-LCS had lower ABC-6 scores and a greater number of falls than those with ET-HCS (P<.05 for all measures) or control subjects (P<.01 for all measures). Quantitative gait measures were significantly correlated with ABC-6 score and falls. Gait speed (P<.007) and ABC-6 score (P<.02) were significant predictors of falls. Receiver operating characteristic curve analysis revealed that gait speed <0.9m/s and ABC-6 score <51% were associated with moderate sensitivity and specificity in identifying fallers. CONCLUSIONS: People with ET-LCS have impaired gait and report lower balance confidence and a higher number of falls than their counterparts (ET-HCS) and than control subjects. We have identified assessments that are easily administered (gait speed, ABC-6 Scale) and are associated with falls in ET.

Beyond Contractures in Spinal Muscular Atrophy: Identifying Lower-Limb Joint Hypermobility.

Background: The natural history of spinal muscular atrophy (SMA) is well understood, with progressive muscle weakness resulting in declines in function. The development of contractures is common and negatively impacts function. Clinically, joint hypermobility (JH) is observed but is poorly described, and its relationship with function is unknown. Methods: Lower-limb ROM (range of motion) assessments of extension and flexion at the hip, knee, and ankle were performed. ROMs exceeding the published norms were included in the analysis. The functional assessments performed included the six-minute walk test (6 MWT) and the Hammersmith Functional Motor Scale-Expanded (HFMSE). Results: Of the 143 participants, 86% (n = 123) had at least one ROM measure that was hypermobile, and 22% (n = 32) had three or more. The HFMSE scores were inversely correlated with hip extension JH (r = -0.60, p = 0.21; n = 6) and positively correlated with knee flexion JH (r = 0.24, p = 0.02, n = 89). There was a moderate, inverse relationship between the 6 MWT distance and ankle plantar flexion JH (r = -0.73, p = 0.002; n = 15). Conclusions: JH was identified in nearly all participants in at least one joint in this study. Hip extension, knee flexion and ankle plantar flexion JH was associated with function. A further understanding of the trajectory of lower-limb joint ROM is needed to improve future rehabilitation strategies.

Falls and spinal muscular atrophy: exploring cause and prevention.

INTRODUCTION: Falls can cause injury and may compromise function in spinal muscular atrophy (SMA) patients. Weakness and gait variability are associated with falls in other neurological disorders, and fatigue is well documented in SMA. The relationship of weakness, fatigue, and gait variability to falls has never been investigated. METHODS: Seven ambulatory patients with SMA completed a falls history questionnaire, 6MWT, gait analysis, and strength testing. Pearson correlation coefficients were used to examine associations between these variables. RESULTS: All 7 subjects reported falls in the previous year. Stride-length variability was significantly associated with falls, unlike strength, fatigue, or other gait variables. CONCLUSIONS: Stride-length variability was the key variable associated with falls. Preventive strategies to avoid falls should be incorporated into patient management plans. Gait analysis provides actionable information not revealed by standard assessments and should be included in clinical trials designed to address the prevention of falls in the SMA population.

Coordination of Care Among Physical Therapists and Neurologists in Huntington Disease.

This study presents a framework for physical therapy through the course of Huntington disease (HD) which includes coordinated care plans with neurologists. HD is an inherited neurodegenerative disorder that leads to impaired strength and coordination and ultimately progressive loss of function. Interdisciplinary HD care teams provide patient-centered, comprehensive evaluations and make recommendations for pharmacologic, healthcare, and lifestyle interventions based on best available evidence. Physical therapists work to improve movement and mobility using specific therapeutic interventions and individualized exercise programs. The proposed framework recommends that neurologists refer persons with HD to physical therapy at all disease stages, ideally beginning in premanifest and early stages, and that they regularly communicate with physical therapists to ensure implementation of a coordinated care plan. Resources are provided for neurologists to facilitate appropriate referral for individuals with HD to physical therapy based on clinical practice guidelines, including a referral decision guide.

Clinical Decision Trees to Guide Physical Therapy Management of Persons with Huntington's Disease.

BACKGROUND: In 2020, our group published physical therapy clinical practice guidelines (CPG) for people with Huntington's disease (HD). The guideline recommendations were categorized according to six primary movement impairment classifications. OBJECTIVE: To facilitate implementation of this CPG, we have developed guideline-based algorithms for physical therapy assessments and interventions and recommendations for therapists to overcome barriers to CPG implementation for people with HD. METHODS: We conducted a literature review of papers that evaluated physical therapy interventions in individuals with HD (n = 26) to identify assessments for each of the primary movement impairment classifications, and then searched for papers (n = 28) that reported their clinometric/psychometric properties in HD. Assessments were evaluated using modified Movement Disorder Society Committee on Rating Scales criteria and other relevant criteria. RESULTS: We identified a "core set" of physical therapy assessments for persons with HD, including the Six Minute Walk Test, Timed Up and Go Test, Berg Balance Scale, and the Medical Outcomes Study Short Form 36 (SF-36). We then developed guideline-based decision trees to assist in decision making and implementation of the CPG into practice for persons with HD across the continuum of care. Finally, we developed strategies for overcoming barriers to implementation, such as seeking specialized training in HD, engaging caretakers or family members to help the person with HD to exercise, and establishing clinical pathways that support early physical therapy referrals. CONCLUSION: Knowledge translation documents such as this are essential to promoting implementation of the physical therapy CPGs into clinical practice.

Gait monitoring for older adults during guided walking: An integrated assistive robot and wearable sensor approach.

An active lifestyle can mitigate physical decline and cognitive impairment in older adults. Regular walking exercises for older individuals result in enhanced balance and reduced risk of falling. In this article, we present a study on gait monitoring for older adults during walking using an integrated system encompassing an assistive robot and wearable sensors. The system fuses data from the robot onboard Red Green Blue plus Depth (RGB-D) sensor with inertial and pressure sensors embedded in shoe insoles, and estimates spatiotemporal gait parameters and dynamic margin of stability in real-time. Data collected with 24 participants at a community center reveal associations between gait parameters, physical performance (evaluated with the Short Physical Performance Battery), and cognitive ability (measured with the Montreal Cognitive Assessment). The results validate the feasibility of using such a portable system in out-of-the-lab conditions and will be helpful for designing future technology-enhanced exercise interventions to improve balance, mobility, and strength and potentially reduce falls in older adults.

Erratum: Gait monitoring for older adults during guided walking: An integrated assistive robot and wearable sensor approach - ERRATUM.

[This corrects the article DOI: 10.1017/wtc.2022.23.].

Transductive Learning Models for Accurate Ambulatory Gait Analysis in Elderly Residents of Assisted Living Facilities.

Instrumented footwear represents a promising technology for spatiotemporal gait analysis in out-of-the-lab conditions. However, moderate accuracy impacts this technology's ability to capture subtle, but clinically meaningful, changes in gait patterns that may indicate adverse outcomes or underlying neurological conditions. This limitation hampers the use of instrumented footwear to aid functional assessments and clinical decision making. This paper introduces new transductive-learning inference models that substantially reduce measurement errors relative to conventional data processing techniques, without requiring subject-specific labelled data. The proposed models use subject-optimized input features and hyperparameters to adjust the spatiotemporal gait metrics (i.e., stride time, length, and velocity, swing time, and double support time) obtained with conventional techniques, resulting in computationally simpler models compared to end-to-end machine learning approaches. Model validity and reliability were evaluated against a gold-standard electronic walkway during a clinical gait performance test (6-minute walk test) administered to N = 95 senior residents of assisted living facilities with diverse levels of gait and balance impairments. Average reductions in absolute errors relative to conventional techniques were -42.0% and -33.5% for spatial and gait-phase parameters, respectively, indicating the potential of transductive learning models for improving the accuracy of instrumented footwear for ambulatory gait analysis.