Symmetry of corticomotor input to plantarflexors influences the propulsive strategy used to increase walking speed post-stroke

Palmer, Jacqueline A.; Hsiao, Hao-Yuan; Awad, Louis N.; Binder‐Macleod, Stuart A.

doi:10.1016/j.clinph.2015.12.003

Cited by 18 publications

(19 citation statements)

References 38 publications

(80 reference statements)

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“…For these individuals, any training centered on improving paretic propulsion (e.g., FastFES) may not be appropriate. Recent work showing that reduced corticomotor input to the paretic plantarflexors is related to asymmetrical interlimb propulsive strategies during walking [ 41 ] supports this alternative hypothesis. Future investigation into how the ability to activate the paretic plantarflexors influences the effects that targeted locomotor training has on the recovery of more physiological gait mechanics and walking function is warranted.…”

Section: Discussionmentioning

confidence: 99%

Identifying candidates for targeted gait rehabilitation after stroke: better prediction through biomechanics-informed characterization

Awad

Reisman

Pohlig

et al. 2016

J NeuroEngineering Rehabil

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BackgroundWalking speed has been used to predict the efficacy of gait training; however, poststroke motor impairments are heterogeneous and different biomechanical strategies may underlie the same walking speed. Identifying which individuals will respond best to a particular gait rehabilitation program using walking speed alone may thus be limited. The objective of this study was to determine if, beyond walking speed, participants’ baseline ability to generate propulsive force from their paretic limbs (paretic propulsion) influences the improvements in walking speed resulting from a paretic propulsion-targeting gait intervention.MethodsTwenty seven participants >6 months poststroke underwent a 12-week locomotor training program designed to target deficits in paretic propulsion through the combination of fast walking with functional electrical stimulation to the paretic ankle musculature (FastFES). The relationship between participants’ baseline usual walking speed (UWSbaseline), maximum walking speed (MWSbaseline), and paretic propulsion (propbaseline) versus improvements in usual walking speed (∆UWS) and maximum walking speed (∆MWS) were evaluated in moderated regression models.ResultsUWSbaseline and MWSbaseline were, respectively, poor predictors of ΔUWS (R2 = 0.24) and ΔMWS (R2 = 0.01). Paretic propulsion × walking speed interactions (UWSbaseline × propbaseline and MWSbaseline × propbaseline) were observed in each regression model (R2s = 0.61 and 0.49 for ∆UWS and ∆MWS, respectively), revealing that slower individuals with higher utilization of the paretic limb for forward propulsion responded best to FastFES training and were the most likely to achieve clinically important differences.ConclusionsCharacterizing participants based on both their walking speed and ability to generate paretic propulsion is a markedly better approach to predicting walking recovery following targeted gait rehabilitation than using walking speed alone.

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Section: Discussionmentioning

confidence: 99%

Identifying candidates for targeted gait rehabilitation after stroke: better prediction through biomechanics-informed characterization

Awad

Reisman

Pohlig

et al. 2016

J NeuroEngineering Rehabil

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“…However, such a threshold has not been defined and likely depends on the type of locomotor rehabilitation being utilized. In addition, it is unclear if individuals with sub-threshold plantarflexor function at baseline are incapable of improving paretic plantarflexor function due to impaired corticomotor function [68] or if reliance on a compensation strategy that hinders propulsion is interfering with their ability to learn a propulsion-based walking strategy [18]. Future work is needed to determine how to identify the cause of subthreshold plantarflexor function at the onset of therapy as well as to develop interventions specific to the underlying cause that are capable of improving Pp.…”

Section: Current Rehabilitation Efforts and Future Directionsmentioning

confidence: 99%

Paretic propulsion as a measure of walking performance and functional motor recovery post-stroke: A review

et al. 2019

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Background: Although walking speed is the most common measure of gait performance poststroke, improved walking speed following rehabilitation does not always indicate the recovery of paretic limb function. Over the last decade, the measure paretic propulsion (Pp, defined as the propulsive impulse generated by the paretic leg divided by the sum of the propulsive impulses of both legs) has been established as a measure of paretic limb output and recently targeted in poststroke rehabilitation paradigms. However, the literature lacks a detailed synthesis of how paretic propulsion, walking speed, and other biomechanical and neuromuscular measures collectively relate to post-stroke walking performance and motor recovery. Objective: The aim of this review was to assess factors associated with the ability to generate Pp and identify rehabilitation targets aimed at improving Pp and paretic limb function. Methods: Relevant literature was collected in which paretic propulsion was used to quantify and assess propulsion symmetry and function in hemiparetic gait. Results: Paretic leg extension during terminal stance is strongly associated with Pp. Both paretic leg extension and propulsion are related to step length asymmetry, revealing an interaction between spatiotemporal, kinematic and kinetic metrics that underlies hemiparetic walking performance. The importance of plantarflexor function in producing propulsion is highlighted by the association of an independent plantarflexor excitation module with increased Pp. Furthermore, the literature suggests that although current rehabilitation techniques can improve Pp, these improvements depend on the patient's baseline plantarflexor function. Significance: Pp provides a quantitative measure of propulsion symmetry and should be a primary target of post-stroke gait rehabilitation. The current literature suggests rehabilitation

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“…The double-cone coil has been used most frequently (Jayaram & Stinear, 2009; Madhavan, Rogers, & Stinear, 2010; Papegaaij, Baudry, et al, 2016; Papegaaij, Taube, Hogenhout, et al, 2014; Papegaaij, Taube, et al, 2016). Other studies have used the batwing coil (Barthelemy et al, 2011; Needle, Palmer, Kesar, Binder-Macleod, & Swanik, 2013; Palmer, Hsiao, Awad, & Binder-Macleod, 2016; Palmer, Hsiao, Wright, & Binder-Macleod, 2017; Palmer, Needle, Pohlig, & Binder-Macleod, 2016; Palmer, Zarzycki, Morton, Kesar, & Binder-Macleod, 2017) and flat figure of eight coil (Smith et al, 2017). The angulation in the batwing and double cone coils helps to increase the depth of penetration of the induced electric field (Deng et al, 2013; Klooster et al, 2016).…”

Section: The Use Of Tms For Studying Lower Limb Musculature Presents mentioning

confidence: 99%

The use of transcranial magnetic stimulation to evaluate cortical excitability of lower limb musculature: Challenges and opportunities

Kesar

Stinear

Wolf

2018

RNN

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Neuroplasticity is a fundamental yet relatively unexplored process that can impact rehabilitation of lower extremity (LE) movements. Transcranial magnetic stimulation (TMS) has gained widespread application as a non-invasive brain stimulation technique for evaluating neuroplasticity of the corticospinal pathway. However, a majority of TMS studies have been performed on hand muscles, with a paucity of TMS investigations focused on LE muscles. This perspective review paper proposes that there are unique methodological challenges associated with using TMS to evaluate corticospinal excitability of lower limb muscles. The challenges include: (1) the deeper location of the LE motor homunculus; (2) difficulty with targeting individual LE muscles during TMS; and (3) differences in corticospinal circuity controlling upper and lower limb muscles. We encourage future investigations that modify traditional methodological approaches to help address these challenges. Systematic TMS investigations are needed to determine the extent of overlap in corticomotor maps for different LE muscles. A simple, yet informative methodological solution involves simultaneous recordings from multiple LE muscles, which will provide the added benefit of observing how other relevant muscles co-vary in their responses during targeted TMS assessment directed toward a specific muscle. Furthermore, conventionally used TMS methods (e.g., determination of hot spot location and motor threshold) may need to be modified for TMS studies involving LE muscles. Additional investigations are necessary to determine the influence of testing posture as well as activation state of adjacent and distant LE muscles on TMS-elicited responses. An understanding of these challenges and solutions specific to LE TMS will improve the ability of neurorehabilitation clinicians to interpret TMS literature, and forge novel future directions for neuroscience research focused on elucidating neuroplasticity processes underlying locomotion and gait training.

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Symmetry of corticomotor input to plantarflexors influences the propulsive strategy used to increase walking speed post-stroke

Cited by 18 publications

References 38 publications

Identifying candidates for targeted gait rehabilitation after stroke: better prediction through biomechanics-informed characterization

Identifying candidates for targeted gait rehabilitation after stroke: better prediction through biomechanics-informed characterization

Paretic propulsion as a measure of walking performance and functional motor recovery post-stroke: A review

The use of transcranial magnetic stimulation to evaluate cortical excitability of lower limb musculature: Challenges and opportunities

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