Quantifying Quality of Reaching Movements Longitudinally Post-Stroke: A Systematic Review

I got nothing out of this other than more research required. And the research required is recovering reaching,  not whatever the hell this research was for. 

Quantifying Quality of Reaching Movements Longitudinally Post-Stroke: A Systematic Review

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M. Saes, MSc*, M. I. Mohamed Refai, PhD*, B. J. F. van Beijnum, PhD, ...

First Published January 31, 2022 Review Article 

https://doi.org/10.1177/15459683211062890

Article information

Background

Disambiguation of behavioral restitution from compensation is important to better understand recovery of upper limb motor control post-stroke and subsequently design better interventions. Measuring quality of movement (QoM) during standardized performance assays and functional tasks using kinematic and kinetic metrics potentially allows for this disambiguation.

Objectives

To identify longitudinal studies that used kinematic and/or kinetic metrics to investigate post-stroke recovery of reaching and assess whether these studies distinguish behavioral restitution from compensation.

Methods

A systematic literature search was conducted using the databases PubMed, Embase, Scopus, and Wiley/Cochrane Library up to July 1st, 2020. Studies were identified if they performed longitudinal kinematic and/or kinetic measurements during reaching, starting within the first 6 months post-stroke.

Results

Thirty-two longitudinal studies were identified, which reported a total of forty-six different kinematic metrics. Although the majority investigated improvements in kinetics or kinematics to quantify recovery of QoM, none of these studies explicitly addressed the distinction between behavioral restitution and compensation. One study obtained kinematic metrics for both performance assays and a functional task.

Conclusions

Despite the growing number of kinematic and kinetic studies on post-stroke recovery, longitudinal studies that explicitly seek to delineate between behavioral restitution and compensation are still lacking in the literature. To rectify this situation, future studies should measure kinematics and/or kinetics during performance assays to isolate restitution and during a standardized functional task to determine the contributions of restitution and compensation.

Keywords

systematic review, stroke, upper extremity, recovery, biomechanics, reaching, kinematics, behavioral restitution, compensation, longitudinal studies

Introduction

About 80% of stroke survivors suffer from upper extremity motor impairment¹ which affects activities of daily living.² Therefore, being able to use the arm to complete functional tasks is among the top ten priorities for stroke survivors, caregivers and health care professionals.³ Upper extremity motor impairment after stroke is comprised of weakness, diminished dexterity and abnormal muscle synergies.⁴

Most patients exhibit some degree of spontaneous recovery of upper extremity motor impairment, with 80-90% of clinical improvements occurring within the first 8-10 weeks post-stroke.^5-7 Studies suggest that reaching movements tend to converge toward healthy patterns, without necessarily returning fully to pre-stroke patterns (ie, partial behavioral restitution).^8-10 The ability to use the upper limb during functional tasks may further improve through the use of compensatory strategies, in which patients accomplish a functional goal in a different way than pre-stroke (ie, behavioral compensation).¹¹ The ability to distinguish between behavioral restitution and compensation would help to better identify interventions that can influence true neurological recovery.

Quality of movement (QoM) reflects the degree of motor control.¹² Despite consensus on a standardized set of clinical measures in stroke studies,¹³ these clinical measures lack the ability to capture small changes in QoM^12,14 and cannot distinguish behavioral restitution from compensation. Longitudinal kinematic studies early after stroke are needed to investigate the time course of QoM of the upper limb. Recommendations on suitable study designs were provided by the Stroke Recovery and Rehabilitation Roundtable (SRRR) task force.¹² The arguments in the body of the paper of the SRRR, which are implicit in the recommendations, suggest kinematic and/or kinetic measurements during 4 standardized performance assays for quantifying behavioral restitution in addition to a functional task to distinguish true recovery from compensation strategies.¹² Performance assays are needed to quantify the different components of motor impairment: weakness, diminished finger individuation and abnormal muscle synergies. Thereby, performance assays were suggested to serve as a proxy for behavioral restitution.¹² To capture these components of impairment, the SRRR defined the following performance assays: grip strength,^15,16 precision grip,¹⁶ finger individuation,^17,18 and 2D planar reaching.^19,20 It was recommended to perform these measurements repeatedly in the first 6 months post-stroke. Moreover, given the nonlinear time course of recovery, these measurements should be repeated more frequently in the first months post-stroke, preferably at fixed times.¹³ Investigating these performance assays is not only important to quantify behavioral restitution the in absence of compensation, the association between performance assays and clinical assessments may also elucidate which motor impairment component is most strongly represented by a clinical assessment score. This may make clear whether, for example, the Fugl-Meyer motor assessment of the upper extremity (FM-UE), a clinical assessment commonly used in stroke rehabilitation, truly captures synergy-driven intra-limb coupling or to which degree it is contaminated by other motor impairment components such as strength.^21,22 Furthermore, to determine the degree to which recovery has converged on normal movement, the SRRR recommended that a healthy control group should be included.¹³ A recent review showed that the number of studies that use kinematics and kinetics to investigate reaching performance is growing exponentially.²³ However, the focus of that particular review was not on longitudinal studies, nor on the metrics that distinguish between behavioral restitution and compensation.

Our objective was to review the literature on the use of kinematic and/or kinetic metrics to measure recovery of QoM after stroke. We focused on upper limb reaching and pointing tasks, as they require coordination of the elbow and shoulder, which is an important component of many daily activities and is often limited post-stroke as a result of weakness, loss of motor control and the intrusion of abnormal muscle synergies.^19,24 We aimed to:

• (1) identify longitudinal studies that used kinematic and/or kinetic metrics reflecting QoM to investigate post-stroke recovery of reaching, to show the reported responsiveness of these metrics over time, and their longitudinal association with clinical measures and

• (2) assess whether these studies have addressed or provided suggestions on how to best capture behavioral restitution and distinguish it from compensation during a reaching task.

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