Aaron E. Embry

Physical Therapy Adjuvants to Promote Optimization of Walking Recovery after Stroke

Stroke commonly results in substantial and persistent deficits in locomotor function. The majority of scientific inquiries have focused on singular intervention approaches, with recent attention given to task specific therapies. We propose that measurement should indicate the most critical limiting factor(s) to be addressed and that a combination of adjuvant treatments individualized to target accompanying impairment(s) will result in the greatest improvements in locomotor function. We explore training to improve walking performance by addressing a combination of: (1) walking specific motor control; (2) dynamic balance; (3) cardiorespiratory fitness and (4) muscle strength and put forward a theoretical framework to maximize the functional benefits of these strategies as physical adjuvants. The extent to which any of these impairments contribute to locomotor dysfunction is dependent on the individual and will undoubtedly change throughout the rehabilitation intervention. Thus, the ability to identify and measure the relative contributions of these elements will allow for identification of a primary intervention as well as prescription of additional adjuvant approaches. Importantly, we highlight the need for future studies as appropriate dosing of each of these elements is contingent on improving the capacity to measure each element and to titrate the contribution of each to optimal walking performance.

Effects of aerobic exercise training on fitness and walking-related outcomes in ambulatory individuals with chronic incomplete spinal cord injury

Study design:Single group, pretest–post-test study.Objectives:To determine the effects of a non-task-specific, voluntary, progressive aerobic exercise training (AET) intervention on fitness and walking-related outcomes in ambulatory adults with chronic motor-incomplete SCI.Setting:Rehabilitation research center.Methods:Ten ambulatory individuals (50% female; 57.94±9.33 years old; 11.11±9.66 years postinjury) completed voluntary, progressive moderate-to-vigorous intensity AET on a recumbent stepper 3 days per week for 6 weeks. The primary outcome measures were aerobic capacity (VO2peak (volume of oxygen that the body can use during physical exertion)) and self-selected overground walking speed (OGWS). Secondary outcome measures included walking economy, 6-minute walk test (6MWT), daily step counts, Walking Index for Spinal Cord Injury (WISCI-II), Dynamic Gait Index (DGI) and Berg Balance Scale (BBS).Results:Nine participants completed all testing and training. Significant improvements in aerobic capacity (P=0.011), OGWS (P=0.023), the percentage of VO2peak used while walking at self-selected speed (P=0.03) and daily step counts (P=0.025) resulted following training.Conclusions:The results indicate that total-body, voluntary, progressive AET is safe, feasible, and effective for improving aerobic capacity, walking speed, and select walking-related outcomes in an exclusively ambulatory SCI sample. This study suggests the potential for non-task-specific aerobic exercise to improve walking following incomplete SCI and builds a foundation for further investigation aimed at the development of exercise based rehabilitation strategies to target functionally limiting impairments in ambulatory individuals with chronic SCI.

Quantifying human movement across the continuum of care: From lab to clinic to community.

UNLABELLED The ability to precisely quantify human movement within the laboratory setting provides researchers with data that comprehensively describe movement dysfunction in clinical cohorts. Furthermore, these data can be effectively utilized to identify potential underlying mechanisms as targets for therapeutic intervention. Although the utility of these methodologies is evidenced by the number of laboratories incorporating these techniques to understand clinical pathologies, the direct translation to clinical practice remains elusive and there exists an information gap between researchers studying these populations and the clinicians developing treatment for the individuals. METHOD Recent technological advancements allow researchers and their clinician counterparts to measure certain elements of human movement outside of the laboratory. Specifically, the use of portable accelerometers allows for calculation of acceleration of the center of mass (COMa) during walking. COMa can be then be used to infer information about force generation by the individual during walking. This information may then be used by researchers to integrate with laboratory based results as well as by clinicians to partner with clinical findings, thus guiding clinical decision making as well as treatment design. The extent to which these types of measurement devices can be used to generate specific data describing human movement away from the lab is in the early stages of investigation, however, the potential for their use is something that could help advance research and patient care in the future.

Rehabilitation of Walking After Stroke

Opinion statementRehabilitation of walking after stroke has been investigated with a variety of interventions, which will be outlined in this review. To date, the majority of interventions have demonstrated a positive, but similar effect in the primary clinical outcome of self-selected walking speed. Consistent among the most successful interventions is a focus on the intensity of the intervention and the ability to progress rehabilitation in a structured fashion. Successful progression of rehabilitation of walking likely lies in the ability to combine interventions based on an understanding of contributing underlying deficits (eg, motor control, strength, cardiovascular endurance, and dynamic balance). Rehabilitation programs must account for the need to train dynamic balance for falls prevention. Lastly, clinicians and researchers need to measure the effects of rehabilitation on participation and health related quality of life.

Feasibility of lower-limb muscle power training to enhance locomotor function poststroke

Poststroke motor control is characterized by greatly reduced muscle power generation. To date, the extent to which muscle power limits walking performance or whether its remediation should be a primary component of locomotor rehabilitation has yet to be established. The purpose of this study was to examine the feasibility and the effects of Poststroke Optimization of Walking using Explosive Resistance training, an intervention aimed at improving poststroke muscular and locomotor function. Twelve subjects (6-60 mo poststroke) participated in 24 training sessions (3 sessions/wk for 8 wk). Exercises included leg press, calf raises, and jump training, all performed at high concentric velocity, as well as trials of fast walking. We measured self-selected and fastest comfortable walking speeds as well as knee extensor and plantar flexor strength and power at pretraining, posttraining, and 8 wk follow-up time points. In addition, we also performed a number of clinical assessments commonly used in poststroke rehabilitation trials. Following training, significant improvements in lower-limb muscle strength and power were realized and accompanied by improvements in self-selected as well as fastest comfortable walking speeds. No changes in clinical assessments resulted from training.

Forced Exercise for Freezing of Gait in Post STN DBS ParkinsonâÂÂs DiseasePatients

Freezing of gait (FoG) is a debilitating condition experienced by Parkinson’s disease (PD) patients whereby they are episodically unable to walk despite their intention to do so. Early, it may occur in the OFF state, and responds to dopaminergic therapy and deep brain stimulation (DBS). FoG can also occur in the ON state, termed non-levodopa responsive FoG (NLR-FoG). The objective of this study was to determine the effects of a forced exercise treadmill protocol on NLR-FoG in patients with PD that had undergone DBS. We recruited five patients to complete a progressive treadmill-training program for six weeks. The freezing of gait questionnaire (FoG-Q) was the primary outcome measure. Patients also completed diaries documenting the number of freezing episodes and falls, the gait and falls questionnaire (GFQ), as well as PD motor and balance assessments pre and post treatment. Objective assessment of spatiotemporal gait parameters were also collected pre and post treatment. We did not see a significant difference in the FoG-Q pre and post treatment. We did see improvements in the MDS-UPDRS in 4/5 patients, and improvements in falls and freezing as measured by diaries in 3/5 patients. Improvement in spatiotemporal gait parameters beyond the minimal detectible change was seen in 2/5 patients. In conclusion, we found that a progressive forced exercise protocol is feasible in patients with PD post DBS, but response to treatment was not uniform. Further larger studies to elucidate factors predictive of response in this patient population are warranted.

The Effects of POWER Training in Young and Older Adults after Stroke.

Background. Approximately 35,000 strokes occur annually in adults below the age of 40, and there is disappointingly little data describing their responses to rehabilitation. The purpose of this analysis was to determine the effects of Poststroke Optimization of Walking using Explosive Resistance (POWER) training in young (<40 years) and older (>60 years) adults and to describe relationships between training-induced improvements in muscular and locomotor function. Methods. Data was analyzed from 16 individuals with chronic stroke who participated in 24 sessions of POWER training. Outcomes included muscle power generation, self-selected walking speed (SSWS), 6-minute walk test, Fugl-Meyer motor assessment, Berg Balance Scale, and Dynamic Gait Index. Results. There were no significant differences between groups at baseline. Within-group comparisons revealed significant improvements in paretic and nonparetic knee extensor muscle power generation in both groups. Additionally, young participants significantly improved SSWS. Improvements in SSWS were more strongly associated with improvements in power generation on both sides in young versus older participants. Conclusions. Younger adults after stroke seem to preferentially benefit from POWER training, particularly when increasing gait speed is a rehabilitation goal. Future research should aim to further understand age-related differences in response to training to provide optimal treatments for all individuals following stroke.

Lower Extremity Strength Is Correlated with Walking Function After Incomplete SCI

BACKGROUND Lower extremity strength has been reported to relate to walking ability, however, the relationship between voluntary lower extremity muscle function as measured by isokinetic dynamometry and walking have not been thoroughly examined in individuals with incomplete spinal cord injury (iSCI). OBJECTIVE To determine the extent to which measures of maximal voluntary isometric contraction (MVIC) and rate of torque development (RTD) in the knee extensor (KE) and plantar flexor (PF) muscle groups correlate with self-selected overground walking speed and spatiotemporal characteristics of walking. METHODS Twenty-two subjects with chronic (>6 months) iSCI participated in a cross-sectional study. Values for MVIC and RTD in the KE and PF muscle groups were determined by isokinetic dynamometry. Walking speed and spatiotemporal characteristics of walking were measured during overground walking. RESULTS MVIC in the KE and PF muscle groups correlated significantly with walking speed. RTD was significantly correlated with walking speed in both muscle groups, the more-involved PF muscle group showing the strongest correlation with walking speed (r = 0.728). RTD in the KE and PF muscle groups of the more-involved limb was significantly correlated with single support time of the more-involved limb. CONCLUSIONS These data demonstrate that lower extremity strength is associated with walking ability after iSCI. Correlations for the muscle groups of the move-involved side were stronger compared to the less-involved limb. In addition, PF function is highlighted as a potential limiting factor to walking speed along with the importance of RTD.

Effects of hip abduction and adduction accuracy on post-stroke gait

Background Gait instability often limits post‐stroke function, although the mechanisms underlying this instability are not entirely clear. Our recent work has suggested that one possible factor contributing to post‐stroke gait instability is a reduced ability to accurately control foot placement. The purpose of the present experiments was to investigate whether post‐stroke gait function is related to the ability to accurately abduct and adduct the hip, as required for accurate foot placement. Methods 35 chronic stroke survivors and 12 age‐matched controls participated in this experiment. Participants performed hip oscillation trials designed to quantify hip abduction/adduction accuracy, in which they lay supine and moved their leg through a prescribed range of motion in time with a metronome. Stroke survivors also performed overground walking trials at their self‐selected speed. Findings 28 of the 35 stroke survivors had sufficient active range of motion to perform the prescribed hip oscillation task. In comparison to controls, these 28 stroke survivors were significantly less accurate at matching the abduction target, matching the adduction target, and moving in time with the metronome. Across these stroke survivors, a multiple regression revealed that only paretic hip abduction accuracy made a unique contribution to predicting paretic step width and paretic step period, metrics of gait performance. Interpretation The present results demonstrate that the ability to accurately abduct the hip is related to post‐stroke gait performance, as predicted from a model‐based gait stabilization strategy. Therefore, interventions designed to improve lower limb movement accuracy may hold promise for restoring post‐stroke gait stability. HighlightsFunctional mobility of individuals with stroke is often limited by gait instability.Accurate mediolateral foot placement typically helps stabilize gait.Individuals with stroke were less accurate at abducting and adducting their paretic hip.Hip abduction accuracy was predictive of post‐stroke gait performance.

Combining therapeutic approaches: rTMS and aerobic exercise in post-stroke depression: a case series

Abstract Objective and importance Residual effects of stroke include well-documented functional limitations and high prevalence of depression. Repetitive transcranial magnetic stimulation (rTMS) and aerobic exercise (AEx) are established techniques that improve depressive symptoms, but a combination of the two has yet to be reported. The purpose of this case series is to examine the safety, feasibility, and impact of combined rTMS and AEx on post-stroke depression and functional mobility. Clinical presentation Three participants with a history of stroke and at least mild depressive symptoms (Patient Health Questionare-9 ≥5). Intervention Both rTMS and AEx were completed 3 times/week for 8-weeks. rTMS was applied to the left dorsolateral prefrontal cortex, 5000 pulses/session at 10 Hz, at an intensity of 120% of resting motor threshold. AEx consisted of 40 min of treadmill walking at 50–70% of heart rate reserve. Results Depressive symptoms improved in all three participants, with all demonstrating response (≥50% improvement in symptoms) and likely remission. All participants improved their Six Minute Walk Test distance and Participants 1 and 2 also improved Berg Balance Scale scores. Participants 1 and 3 improved overground walking speeds. No serious adverse events occurred with the application of rTMS or AEx and the participants’ subjective reports indicated positive responses. Adherence rate for both rTMS and AEx was 98%. Conclusion Combined treatment of rTMS and AEx appears safe, feasible, and tolerable in individuals with a history of stroke and at least mild depressive symptoms. All participants had good compliance and demonstrated improvements in both depressive symptoms and walking capacity.