Trudy A. Pelton

Hemiparetic Stepping to the Beat: Asymmetric Response to Metronome Phase Shift During Treadmill Gait

Background. Walking in time with a metronome is associated with improved spatiotemporal parameters in hemiparetic gait; however, the mechanism linking auditory and motor systems is poorly understood. Objective. Hemiparetic cadence control with metronome synchronization was examined to determine specific influences of metronome timing on treadmill walking. Methods. A within-participant experiment examined correction processes used to maintain heel strike synchrony with the beat by applying perturbations to the timing of a metronome. Eight chronic hemiparetic participants (mean age = 70 years; standard deviation = 12) were required to synchronize heel strikes with metronome pulses set according to each individual’s comfortable speed (mean 0.4 m/s). During five 100-pulse trials, a fixed-phase baseline was followed by 4 unpredictable metronome phase shifts (20% of the interpulse interval), which amounted to 10 phase shifts on each foot. Infrared cameras recorded the motion of bilateral heel markers at 120 Hz. Relative asynchrony between heel strike responses and metronome pulses was used to index compensation for metronome phase shifts. Results. Participants demonstrated compensation for phase shifts with convergence back to pre—phase shift asynchrony. This was significantly slower when the error occurred on the nonparetic side (requiring initial correction with the paretic limb) compared with when the error occurred on the paretic side (requiring initial nonparetic correction). Conclusions . Although phase correction of gait is slowed when the phase shift is delivered to the nonparetic side compared with the paretic side, phase correction is still present. This may underlie the utility of rhythmic auditory cueing in hemiparetic gait rehabilitation.

Interventions for coordination of walking following stroke: Systematic review

Impairments in gait coordination may be a factor in falls and mobility limitations after stroke. Therefore, rehabilitation targeting gait coordination may be an effective way to improve walking post-stroke. This review sought to examine current treatments that target impairments of gait coordination, the theoretical basis on which they are derived and the effects of such interventions. Few high quality RCTs with a low risk of bias specifically targeting and measuring restoration of coordinated gait were found. Consequently, we took a pragmatic approach to describing and quantifying the available evidence and included non-randomised study designs and limited the influence of heterogeneity in experimental design and control comparators by restricting meta-analyses to pre- and post-test comparisons of experimental interventions only. Results show that physiotherapy interventions significantly improved gait function and coordination. Interventions involving repetitive task-specific practice and/or auditory cueing appeared to be the most promising approaches to restore gait coordination. The fact that overall improvements in gait coordination coincided with increased walking speed lends support to the hypothesis that targeting gait coordination gait may be a way of improving overall walking ability post-stroke. However, establishing the mechanism for improved locomotor control requires a better understanding of the nature of both neuroplasticity and coordination deficits in functional tasks after stroke. Future research requires the measurement of impairment, activity and cortical activation in an effort to establish the mechanism by which functional gains are achieved.

Interventions for improving coordination of reach to grasp following stroke: a systematic review.

BACKGROUND Stroke is associated with disruption to efficient and accurate reach to grasp function. Information about treatments for upper limb coordination deficits and their effectiveness may contribute to improved recovery of upper limb function after stroke. AIMS To identify all existing interventions targeted at coordination of arm and hand segments for reach to grasp following stroke. To determine the effectiveness of current treatments for improving coordination of reach to grasp after stroke. SEARCH STRATEGY The search included The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); MEDLINE; EMBASE; CINAHL; AMED; ProQuest Dissertations and Theses (International) and ISI Proceedings (Conference) databases. A grey literature search included Mednar, Dissertation International, Conference Proceedings, National Institute of Health Clinical Trials and the National Institute of Clinical Studies. We also explored Physiotherapy Evidence Database, Chartered Society of Physiotherapy Research and REHABDATA therapy databases. Finally, the reference lists of identified articles were examined for additional studies. The search spanned from 1950 to April 2010 and was limited to English language papers only. METHODS OF THE REVIEW Studies were included with a specific design objective related to coordination of the hand and arm during reach to grasp and involving participants with a clinical diagnosis of stroke. The review was inclusive with regard to study design. To determine effectiveness of interventions we analysed studies with coordination measures that exist within impairment measurement scales or specific kinematic measures of coordination. The methodological quality of the studies was assessed by two independent authors using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Comparable Cohort/Case Control and the JBI Critical Appraisal Checklist for Experimental Studies together with additional questions from Downs and Black. Two review authors independently extracted data from the studies using standardised JBI-MAStARI data extraction forms. Pooling of results was not appropriate so the findings were summarised in tables and in narrative form. RESULTS One randomised controlled trial, two case-control studies and four experimental studies without controls were included in this review. The review has identified three categories of potential intervention for improving hand and arm coordination after stroke; functional therapy, biofeedback or electrical stimulation and robot or computerised training. In view of the limited availability of good quality evidence and lack of empirical data, this review does not draw a definitive conclusion for the second question regarding the effectiveness of interventions aimed at improving hand and arm coordination after stroke. Improvements in hand and arm coordination during reach to grasp were reported in four studies, whereas one study found no benefit. Two studies did not report specific effects of interventions for hand and arm coordination after stroke. CONCLUSIONS IMPLICATIONS FOR PRACTICE There is currently insufficient evidence to provide strong recommendations about the effect of interventions for improving hand and arm coordination during reach to grasp after stroke. IMPLICATIONS FOR RESEARCH Randomised controlled trials of sufficient power with standardised outcome measures are needed to enable meta-analysis comparison in the future. Such studies should include both functional performance and detailed kinematic measures of hand and arm coordination.

Seated bilateral leg exercise effects on hemiparetic lower extremity function in chronic stroke.

Background. Bilateral arm training with rhythmic auditory cueing (BATRAC) improves hemiparetic upper extremity (UE) function in stroke. It is unknown whether a similar exercise for the hemiparetic lower extremity (LE) is effective. Objective. The authors sought to test whether the BATRAC strategy would transfer to the legs by improving LE motor function following ten 30-minute sessions of bilateral leg training with rhythmic auditory cueing (BLETRAC). Methods. Twenty-four chronic stroke participants, recruited from the community, were randomized to either the BLETRAC or the BATRAC intervention. Assessments were performed before (week 0) and after (week 6) training as well as 3 months later (week 18). Change in the Fugl-Meyer LE and UE subscales served as primary outcomes. Timed 10-m walk, movement parameters during treadmill walking, and a repetitive aiming task for both feet and hands were the secondary outcomes. Results . Following an intention-to-treat approach, data from 21 subjects were analyzed. After training, improvements in the Fugl-Meyer LE and UE subscales tended to be better for the corresponding intervention group. The BLETRAC group also showed increases in step length during treadmill walking and performance in the repetitive foot and hand aiming tasks. No differences between the intervention groups were found at follow-up. Conclusions. This exploratory trial demonstrates that transfer of the BATRAC approach to the legs is feasible. Transient improvements of limb motor function in chronic stroke participants were induced by targeted exercise (BATRAC for the UE and BLETRAC for the LE). It may be that further periods of training would increase and maintain effects.

Neuroscience Findings on Coordination of Reaching to Grasp an Object: Implications for Research

Background. Knowledge of how damage to brain regions and pathways affects central nervous system control of coordination of reach-to-grasp (RTG) following stroke may not be sufficiently used in existing treatment interventions or in research that assesses their effectiveness. Objective. To review current knowledge of motor control of coordination of RTG and discuss the extent to which this information is being used in research evaluating treatment interventions. Method. This review (1) summarizes the current knowledge of motor control of RTG coordination in healthy individuals, including speculative models and structures of the brain identified as being involved; (2) summarizes evidence of RTG coordination deficits in people with stroke; (3) evaluates current interventions directed at retraining coordination of RTG, including a review of the extent to which these interventions are based on putative neurobiological mechanisms and reports on their effectiveness; and (4) recommends directions for research on treatment interventions for coordination of RTG. Results. Functional task-specific therapy, electrical stimulation, and robot or computerized training were identified as treatments targeted at improving coordination of RTG. However, none of the studies reporting the effect of these interventions related results to individual brain regions affected, and neurobiological mechanisms underlying improved performance were only minimally discussed. Conclusions. Research on treatment interventions for coordination of RTG needs to combine measures of interruption to brain networks and how remaining intact neural tissue and networks respond to therapy with measures of spatiotemporal motor control and upper-limb function to gain a fuller understanding of treatment effects and their mechanisms.

Feasibility and Preliminary Efficacy of Visual Cue Training to Improve Adaptability of Walking after Stroke: Multi-Centre, Single-Blind Randomised Control Pilot Trial

Objectives Given the importance of vision in the control of walking and evidence indicating varied practice of walking improves mobility outcomes, this study sought to examine the feasibility and preliminary efficacy of varied walking practice in response to visual cues, for the rehabilitation of walking following stroke. Design This 3 arm parallel, multi-centre, assessor blind, randomised control trial was conducted within outpatient neurorehabilitation services Participants Community dwelling stroke survivors with walking speed <0.8m/s, lower limb paresis and no severe visual impairments Intervention Over-ground visual cue training (O-VCT), Treadmill based visual cue training (T-VCT), and Usual care (UC) delivered by physiotherapists twice weekly for 8 weeks. Main outcome measures: Participants were randomised using computer generated random permutated balanced blocks of randomly varying size. Recruitment, retention, adherence, adverse events and mobility and balance were measured before randomisation, post-intervention and at four weeks follow-up. Results Fifty-six participants participated (18 T-VCT, 19 O-VCT, 19 UC). Thirty-four completed treatment and follow-up assessments. Of the participants that completed, adherence was good with 16 treatments provided over (median of) 8.4, 7.5 and 9 weeks for T-VCT, O-VCT and UC respectively. No adverse events were reported. Post-treatment improvements in walking speed, symmetry, balance and functional mobility were seen in all treatment arms. Conclusions Outpatient based treadmill and over-ground walking adaptability practice using visual cues are feasible and may improve mobility and balance. Future studies should continue a carefully phased approach using identified methods to improve retention. Trial Registration Clinicaltrials.gov NCT01600391

Visual cue training to improve walking and turning after stroke: a study protocol for a multi-centre, single blind randomised pilot trial

BackgroundVisual information comprises one of the most salient sources of information used to control walking and the dependence on vision to maintain dynamic stability increases following a stroke. We hypothesize, therefore, that rehabilitation efforts incorporating visual cues may be effective in triggering recovery and adaptability of gait following stroke. This feasibility trial aims to estimate probable recruitment rate, effect size, treatment adherence and response to gait training with visual cues in contrast to conventional overground walking practice following stroke.Methods/designA 3-arm, parallel group, multi-centre, single blind, randomised control feasibility trial will compare overground visual cue training (O-VCT), treadmill visual cue training (T-VCT), and usual care (UC). Participants (n = 60) will be randomly assigned to one of three treatments by a central randomisation centre using computer generated tables to allocate treatment groups. The research assessor will remain blind to allocation. Treatment, delivered by physiotherapists, will be twice weekly for 8 weeks at participating outpatient hospital sites for the O-VCT or UC and in a University setting for T-VCT participants.Individuals with gait impairment due to stroke, with restricted community ambulation (gait speed <0.8m/s), residual lower limb paresis and who are able to take part in repetitive walking practice involving visual cues (i.e., no severe visual impairments, able to walk with minimal assistance and no comorbid medical contraindications for walking practice) will be included.The primary outcomes concerning participant enrolment, recruitment, retention, and health and social care resource use data will be recorded over a recruitment period of 18 months. Secondary outcome measures will be undertaken before randomisation (baseline), after the eight-week intervention (outcome), and at three months (follow-up). Outcome measures will include gait speed and step length symmetry; time and steps taken to complete a 180° turn; assessment of gait adaptability (success rate in target stepping); timed up and go; Fugl-Meyer lower limb motor assessment; Berg balance scale; falls efficacy scale; SF-12; and functional ambulation category.DiscussionParticipation and compliance measured by treatment logs, accrual rate, attrition, and response variation will determine sample sizes for an early phase randomised controlled trial and indicate whether a definitive late phase efficacy trial is justified.Trial registrationClinicaltrials.gov, NCT01600391.

A novel and simple test of gait adaptability predicts gold standard measures of functional mobility in stroke survivors

BACKGROUND Although there is evidence that stroke survivors have reduced gait adaptability, the underlying mechanisms and the relationship to functional recovery are largely unknown. We explored the relationships between walking adaptability and clinical measures of balance, motor recovery and functional ability in stroke survivors. METHODS Stroke survivors (n=42) stepped to targets, on a 6m walkway, placed to elicit step lengthening, shortening and narrowing on paretic and non-paretic sides. The number of targets missed during six walks and target stepping speed was recorded. Fugl-Meyer (FM), Berg Balance Scale (BBS), self-selected walking speed (SWWS) and single support (SS) and step length (SL) symmetry (using GaitRite when not walking to targets) were also assessed. Stepwise multiple-linear regression was used to model the relationships between: total targets missed, number missed with paretic and non-paretic legs, target stepping speed, and each clinical measure. RESULTS Regression revealed a significant model for each outcome variable that included only one independent variable. Targets missed by the paretic limb, was a significant predictor of FM (F(1,40)=6.54, p=0.014,). Speed of target stepping was a significant predictor of each of BBS (F(1,40)=26.36, p<0.0001), SSWS (F(1,40)=37.00, p<0.0001). No variables were significant predictors of SL or SS asymmetry. DISCUSSION Speed of target stepping was significantly predictive of BBS and SSWS and paretic targets missed predicted FM, suggesting that fast target stepping requires good balance and accurate stepping demands good paretic leg function. The relationships between these parameters indicate gait adaptability is a clinically meaningful target for measurement and treatment of functionally adaptive walking ability in stroke survivors.

Differential effects of parietal and cerebellar stroke in response to object location perturbation

Background The differential contributions of the cerebellum and parietal lobe to coordination between hand transport and hand shaping to an object have not been clearly identified. Objective To contrast impairments in reach-to-grasp coordination, in response to object location perturbation, in patients with right parietal and cerebellar lesions, in order to further elucidate the role of each area in reach-to-grasp coordination. Method A two-factor design with one between subject factor (right parietal stroke; cerebellar stroke; controls) and one within subject factor (presence or absence of object location perturbation) examined correction processes used to maintain coordination between transport-to-grasp in the presence of perturbation. Sixteen chronic stroke participants (eight with right parietal lesions and eight with cerebellar lesions) were matched in age (mean = 61 years; standard deviation = 12) and hand dominance with 16 healthy controls. Hand and arm movements were recorded during unperturbed baseline trials (10) and unpredictable trials (60) in which the target was displaced to the left (10) or right (10) or remained fixed (40). Results Cerebellar patients had a slowed response to perturbation with anticipatory hand opening, an increased number of aperture peaks and disruption to temporal coordination, and greater variability. Parietal participants also exhibited slowed movements, with increased number of aperture peaks, but in addition, increased the number of velocity peaks and had a longer wrist path trajectory due to difficulties planning the new transport goal and thus relying more on feedback control. Conclusion Patients with parietal or cerebellar lesions showed some similar and some contrasting deficits. The cerebellum was more dominant in controlling temporal coupling between transport and grasp components, and the parietal area was more concerned with using sensation to relate arm and hand state to target position.