Referent control of side-to-side body-weight transfer during standing and stepping in adults.

Research suggests that locomotion may be primarily caused by shifting stable body balance from one location in the environment to another with subsequent rhythmical muscle activation by the central pattern generator (CPG), constituting a multi-level control system. All levels interact with environmental forces affected by proprioceptive and vestibular reflexes as well as vision. A similar multi-level control schema is likely used to shift body balance laterally when the body weight is rhythmically transferred from side-to-side. In order to do so, the system shifts a specific body posture in space. This body posture is referred to as the threshold or referent body posture, R, at which all muscles involved can be at rest but are activated depending on the deflection of the actual body posture, Q, from R. This concept has previously been investigated for forward and backward locomotion. The purpose of the present study was to verify if it was also applicable to locomotor tasks in other directions such as sidestepping. We predicted that during sidestepping, the actual and referent posture can transiently match each other bringing the activity of multiple muscles to a minimum. The existence of such minima was demonstrated in healthy adults performing three locomotor tasks involving shifts of the body weight from side-to-side thus further supporting the validity of the multi-level control scheme of locomotion.

Altered Anticipatory Postural Adjustments During Whole-Body Reaching in Subjects With Stroke.

BACKGROUND: Coordination between arm movements and postural adjustments is crucial for reaching-while-stepping tasks involving both anticipatory postural adjustments (APAs) and compensatory movements to effectively propel the whole-body forward so that the hand can reach the target. Stroke impairs the ability to coordinate the action of multiple body segments but the underlying mechanisms are unclear. Objective. To determine the effects of stroke on reaching performance and APAs during whole-body reaching. METHODS: We tested arm reaching in standing (stand-reach) and reaching-while-stepping (step-reach; 15 trials/condition) in individuals with chronic stroke (n = 18) and age-matched healthy subjects (n = 13). Whole-body kinematics and kinetic data were collected during the tasks. The primary outcome measure for step-reach was "gain" (g), defined as the extent to which the hip displacement contributing to hand motion was neutralized by appropriate changes in upper limb movements (g = 1 indicates complete compensation) and APAs measured as spatio-temporal profiles of the center-of-pressure shifts preceding stepping. RESULTS: Individuals with stroke had lower gains and altered APAs compared to healthy controls. In addition, step onset was delayed, and the timing of endpoint, trunk, and foot movement offset was prolonged during step-reach compared to healthy controls. Those with milder sensorimotor impairment and better balance function had higher gains. Altered APAs were also related to reduced balance function. CONCLUSIONS: Altered APAs and prolonged movement offset in stroke may lead to a greater reliance on compensatory arm movements. Altered APAs in individuals with stroke may be associated with a reduced shift of referent body configuration during the movement.

Uptake of Technology for Neurorehabilitation in Clinical Practice: A Scoping Review.

OBJECTIVE: Technology-based interventions offer many opportunities to enhance neurorehabilitation, with associated research activity gathering pace. Despite this fact, translation for use in clinical practice has lagged research innovation. An overview of the current "state of play" regarding the extent of clinical uptake and factors that might influence use of technologies is required. This scoping review explored the uptake of technologies as neurorehabilitation interventions in clinical practice and factors that are reported to influence their uptake. METHODS: This systematic scoping review was conducted with narrative synthesis and evidence mapping. Studies of any design reporting uptake or implementation of technology (wearable devices, virtual reality, robotics, and exergaming) for movement neurorehabilitation after stroke and other neurological conditions were sought via a formal search strategy in MEDLINE (Ovid), CINAHL, AMED, and Embase. Full-text screening and data extraction were completed independently by 2 reviewers. RESULTS: Of 609 studies returned, 25 studies were included after title, abstract, and full-text screening. Studies investigated a range of technologies at various stages of development. Only 4 of the included studies explored the sustained use of technology in practice. The following 5 themes representing experiences of technology use emerged: perceived usefulness, technology design, social interaction, integration with services, and suggested improvements to enhance uptake. CONCLUSION: Reporting of uptake and use of neurorehabilitation technologies in clinical practice is limited. The synthesis provided comprehensive knowledge of barriers to and facilitators of uptake to be considered in future protocols, including a steep learning curve required to engage with technology, a need for a supportive organizational culture, and a need for user involvement in both design and development. IMPACT: This scoping review has provided indicators from current evidence of important factors to consider in the planning of research into and clinical implementation of technologies for neurorehabilitation. It serves to support an evidence-based, user-centered platform for improved research on and translation of technologies in neurorehabilitation clinical practice.

Environment-based approaches to improve participation of young people with physical disabilities during COVID-19.

AIM: To examine the effects of the Pathways and Resources for Engagement and Participation (PREP) intervention during the COVID-19 pandemic on (1) activity performance and satisfaction, and (2) motor, cognitive, and affective body functions. METHOD: An interrupted time-series design with multiple baselines across 21 young people (13 females, eight males) aged 16 to 25 years (median = 21 years 5 months) with physical disabilities was employed. The young people engaged in an 8-week self-chosen leisure activity (e.g. football, piano, photography) at their home or community. The Canadian Occupational Performance Measure (COPM) assessed activity performance and satisfaction weekly. Mental health problems, including affective and cognitive outcomes, were assessed weekly using the Behavior Assessment System for Children, Third Edition. Motor functions (e.g. trunk control, reaching, strength) were assessed biweekly. Linear mixed-effects models were used. RESULTS: The intervention had large effects on activity performance (0.78) and satisfaction (0.88) with clinically significant change in COPM scores (2.6 [95% confidence interval {CI}: 2.0-3.2] and 3.2 points [95% CI: 2.4-3.9] respectively). Young people without mental health problems at baseline benefited more from the intervention (p = 0.028). Improvements in at least one domain of body function occurred in 10 young people especially for motor outcomes. INTERPRETATION: Results demonstrate the effectiveness of PREP during adverse times and suggest benefits going beyond participation, involving outcomes at the body-function level.

ENHANCE proof-of-concept three-arm randomized trial: effects of reaching training of the hemiparetic upper limb restricted to the spasticity-free elbow range.

Post-stroke motor recovery processes remain unknown. Timescales and patterns of upper-limb (UL) recovery suggest a major impact of biological factors, with modest contributions from rehabilitation. We assessed a novel impairment-based training motivated by motor control theory where reaching occurs within the spasticity-free elbow range. Patients with subacute stroke (≤ 6 month; n = 46) and elbow flexor spasticity were randomly allocated to a 10-day UL training protocol, either personalized by restricting reaching to the spasticity-free elbow range defined by the tonic stretch reflex threshold (TSRT) or non-personalized (non-restricted) and with/without anodal transcranial direct current stimulation. Outcomes assessed before, after, and 1 month post-intervention were elbow flexor TSRT angle and reach-to-grasp arm kinematics (primary) and stretch reflex velocity sensitivity, clinical impairment, and activity (secondary). Results were analyzed for 3 groups as well as those of the effects of impairment-based training. Clinical measures improved in both groups. Spasticity-free range training resulted in faster and smoother reaches, smaller (i.e., better) arm-plane path length, and closer-to-normal shoulder/elbow movement patterns. Non-personalized training improved clinical scores without improving arm kinematics, suggesting that clinical measures do not account for movement quality. Impairment-based training within a spasticity-free elbow range is promising since it may improve clinical scores together with arm movement quality.Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique Identifier: NCT02725853; Initial registration date: 01/04/2016.

Responsiveness of the Reaching Performance Scale for Stroke.

OBJECTIVE: The objective of the study was to estimate the internal and external responsiveness of the Reaching Performance Scale for Stroke (RPSS) in individuals with stroke. DESIGN: Retrospective analysis of data from 4 randomized controlled trials. SETTING: Recruitment locations spanning rehabilitation centers and hospitals in Canada, Italy, Argentina, Peru, and Thailand. PARTICIPANTS: Data from 567 participants (acute to chronic stroke; N=567) were available. INTERVENTIONS: All 4 studies involved training using virtual reality for upper limb rehabilitation. MAIN OUTCOME MEASURES: RPSS and upper extremity Fugl-Meyer Assessment (FMA-UE) scores. Responsiveness was quantified for all data and across different stages of stroke. Internal responsiveness of the RPSS was quantified as effect-sizes calculated using post and preintervention change data. External responsiveness was quantified using orthogonal regressions between FMA-UE and RPSS scores. The area under the Receiver Operating Characteristic curve (AUC) was quantified based on the ability of RPSS scores to detect change above FMA-UE minimal clinically important different values across different stages of stroke. RESULTS: The RPSS had high internal responsiveness overall and across the acute or subacute and chronic stages of stroke. For external responsiveness, orthogonal regression analyses indicated that change in FMA-UE scores had positive moderate correlations with both RPSS Close and Far Target scores for all data and across the acute or subacute and chronic stages of stroke (0.6

Identifying Referent Control Variables Underlying Goal-Directed Arm Movements.

The referent control theory (RCT) for action and perception is an advanced formulation of the equilibrium-point hypothesis. The RCT suggests that rather than directly specifying the desired motor outcome, the nervous system controls action and perception indirectly by setting the values of parameters of physical and physiological laws. This is done independently of values of kinematic and kinetic variables including electromyographic patterns describing the motor outcome. One such parameter-the threshold muscle length, λ, at which motoneurons of a given muscle begin to be recruited, has been identified experimentally. In RCT, a similar parameter, the referent arm position, R, has been defined for multiple arm muscles as the threshold arm position at which arm muscles can be quiescent but activated depending on the deflection of the actual arm position, Q, from R. Changes in R result in reciprocal changes in the activity of opposing muscle groups. We advanced the explanatory power of RCT by combining the usual biomechanical descriptions of motor actions with the identification of the timing of R underlying arm movements made with reversals in three directions and to three different extents. We found that in all movements, periods of minimization of the activity of multiple muscles could be identified at ∼61%-86% of the reaching extent in each direction. These electromyographic minimization periods reflect the spatial coordinates at which the R and Q overlap during the production of movements with reversals. The findings support the concept of the production of arm movement by shifting R.

Reaction of human walking to transient block of vision: analysis in the context of indirect, referent control of motor actions.

Human locomotion may result from monotonic shifts in the referent position, R, of the body in the environment. R is also the spatial threshold at which muscles can be quiescent but are activated depending on the deflection of the current body configuration Q from R. Shifts in R are presumably accomplished with the participation of proprioceptive and visual feedback and responsible for transferring stable body balance (equilibrium) from one place in the environment to another, resulting in rhythmic activity of multiple muscles by a central pattern generator (CPG). We tested predictions of this two-level control scheme. In particular, in response to a transient block of vision during locomotion, the system can temporarily slow shifts in R. As a result, the phase of rhythmical movements of all four limbs will be changed for some time, even though the rhythm and other characteristics of locomotion will be fully restored after perturbation, a phenomenon called long-lasting phase resetting. Another prediction of the control scheme is that the activity of multiple muscles of each leg can be minimized reciprocally at specific phases of the gait cycle both in the presence and absence of vision. Speed of locomotion is related to the rate of shifts in the referent body position in the environment. Results confirmed that human locomotion is likely guided by feedforward shifts in the referent body location, with subsequent changes in the activity of multiple muscles by the CPG. Neural structures responsible for shifts in the referent body configuration causing locomotion are suggested.

Psychometric Properties of a New Measure of Upper Limb Performance in Post-Stroke Individuals: Trunk-Based Index of Performance.

BACKGROUND: Several measures of upper limb (UL) motor tasks have been developed to characterize recovery. However, UL performance and movement quality measures in isolation may not provide a true profile of functional recovery. OBJECTIVE: To investigate the measurement properties of a new trunk-based Index of Performance (IPt) of the UL combining endpoint performance (accuracy and speed) and movement quality (trunk displacement) in stroke. METHODS: Participants with stroke (n = 25, mean time since stroke: 18.7 ± 17.2 months) performed a reaching task over 3 evaluation sessions. The IPt was computed based on Fitts' Law that incorporated endpoint accuracy and speed corrected by the amount of trunk displacement. Test-retest reliability was analyzed using intraclass correlation coefficient (ICC) and Bland-Altman plots. Standard error of measurement (SEM) and Minimal Detectable Change (MDC) were determined. Validity was investigated through the relationship between IPt, Fugl-Meyer Assessment (FMA-UE), and Action Research Arm Test (ARAT), as well as the ability of IPt to distinguish between levels of UL motor impairment severity. RESULTS: Test-retest reliability was excellent (ICC = .908, 95% CI: 0.807-0.96). Bland-Altman did not show systematic differences. SEM and MDC95 were 14% and 39%, respectively. Construct validity was satisfactory. The IPt showed low-to-moderate relationships with FMA-UE (R2 ranged from .236 to .428) and ARAT (R2 ranged from .277 to .306). IPt scores distinguished between different levels of UL severity. CONCLUSIONS: The IPt showed evidence of good reliability, and initial validity. The IPt may be a promising tool for research and clinical settings. Further research is warranted to investigate its validity with additional comparator instruments.

Virtual Reality-Based Rehabilitation as a Feasible and Engaging Tool for the Management of Chronic Poststroke Upper-Extremity Function Recovery: Randomized Controlled Trial.

BACKGROUND: A growing number of stroke survivors are left with little to no rehabilitation services upon discharge from stroke rehabilitation, although arm deficits may persist or develop from disuse once rehabilitation services have ceased. Virtual reality (VR)-based rehabilitation, combined with new technologies such as telerehabilitation, including serious games using VR environments that encourage users to practice functional movements from home with minimal supervision, may have an important role to play in optimizing and maintaining upper extremity (UE) function. OBJECTIVE: The primary objective of this study is to determine the extent to which a 1-month intervention using a VR-based serious game is effective in improving UE function compared with an evidence-based home exercise program. A secondary objective is to assess the feasibility of implementing the intervention for chronic stroke rehabilitation in participants' homes. METHODS: A total of 51 chronic stroke participants were randomized to treatment (n=26, 51%; Jintronix system) or standard care (n=25, 49%; standardized Graded Repetitive Arm Supplementary Program kit home program) groups. The participants were evaluated at baseline (before), immediately after the intervention (after), and at follow-up (4 weeks). The primary outcome measure was the Fugl-Meyer Assessment for UE (FMA-UE). Secondary outcome measures included the Stroke Impact Scale and an abridged version of the Motor Activity Log-14. Self-reported number of sessions was logged for the standard care group. RESULTS: No statistically significant differences between groups were found across measures. Overall time effects were found for the FMA-UE (P=.045), specifically between preintervention and postintervention time points for both groups (P=.03). A total of 9 participants in the treatment group reached or surpassed the minimal clinically important difference in scores for the FMA-UE, with 7 (78%) of them having baseline low or moderate arm function, compared with 3 (33%) participants in the standard care group. Furthermore, 56% (9/16) of the participants in the treatment group who actively engaged with the system reached the minimal clinically important difference for the FMA-UE, compared with none for the 0% (0/10) less-active participants. CONCLUSIONS: These findings suggest that UE training for chronic stroke survivors using virtual rehabilitation in their home may be as effective as a gold standard home exercise program and that those who used the system the most achieved the greatest improvement in UE function, indicating its relevance to being included as part of ongoing rehabilitation services. TRIAL REGISTRATION: ClinicalTrials.gov NCT02491203; https://clinicaltrials.gov/ct2/show/NCT02491203. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1016/j.cct.2015.12.006.

Motor Control: A Conceptual Framework for Rehabilitation.

There is a lack of conceptual and theoretical clarity among clinicians and researchers regarding the control of motor actions based on the use of the term "motor control." It is important to differentiate control processes from observations of motor output to improve communication and to make progress in understanding motor disorders and their remediation. This article clarifies terminology related to theoretical concepts underlying the control of motor actions, emphasizing how the term "motor control" is applied in neurorehabilitation. Two major opposing theoretical frameworks are described (i.e., direct and indirect), and their strengths and pitfalls are discussed. Then, based on the proposition that sensorimotor rehabilitation should be predicated on one comprehensive theory instead of an eclectic mix of theories and models, several solutions are offered about how to address controversies in motor learning, optimality, and adaptability of movement.

Shared and distinct voxel-based lesion-symptom mappings for spasticity and impaired movement in the hemiparetic upper limb.

Hemiparesis and spasticity are common co-occurring manifestations of hemispheric stroke. The relationship between impaired precision and force in voluntary movement (hemiparesis) and the increment in muscle tone that stems from dysregulated activity of the stretch reflex (spasticity) is far from clear. Here we aimed to elucidate whether variation in lesion topography affects hemiparesis and spasticity in a similar or dis-similar manner. Voxel-based lesion-symptom mapping (VLSM) was used to assess the impact of lesion topography on (a) upper limb paresis, as reflected by the Fugl-Meyer Assessment scale for the upper limb and (b) elbow flexor spasticity, as reflected by the Tonic Stretch Reflex Threshold, in 41 patients with first-ever stroke. Hemiparesis and spasticity were affected by damage to peri-Sylvian cortical and subcortical regions and the putamen. Hemiparesis (but not spasticity) was affected by damage to the corticospinal tract at corona-radiata and capsular levels, and by damage to white-matter association tracts and additional regions in the temporal cortex and pallidum. VLSM conjunction analysis showed only a minor overlap of brain voxels where the existence of damage affected both hemiparesis and spasticity, suggesting that control of voluntary movement and regulation of muscle tone at rest involve largely separate parts of the motor network.

Exercise intensity of the upper limb can be enhanced using a virtual rehabilitation system.

PURPOSE: Motor recovery of the upper limb (UL) is related to exercise intensity, defined as movement repetitions divided by minutes in active therapy, and task difficulty. However, the degree to which UL training in virtual reality (VR) applications deliver intense and challenging exercise and whether these factors are considered in different centres for people with different sensorimotor impairment levels is not evidenced. We determined if (1) a VR programme can deliver high UL exercise intensity in people with sub-acute stroke across different environments and (2) exercise intensity and difficulty differed among patients with different levels of UL sensorimotor impairment. METHODS: Participants with sub-acute stroke (<6 months) with Fugl-Meyer scores ranging from 14 to 57, completed 10 ∼ 50-min UL training sessions using three unilateral and one bilateral VR activity over 2 weeks in centres located in three countries. Training time, number of movement repetitions, and success rates were extracted from game activity logs. Exercise intensity was calculated for each participant, related to UL impairment, and compared between centres. RESULTS: Exercise intensity was high and was progressed similarly in all centres. Participants had most difficulty with bilateral and lateral reaching activities. Exercise intensity was not, while success rate of only one unilateral activity was related to UL severity. CONCLUSION: The level of intensity attained with this VR exercise programme was higher than that reported in current stroke therapy practice. Although progression through different activity levels was similar between centres, clearer guidelines for exercise progression should be provided by the VR application.Implications for rehabilitationVR rehabilitation systems can be used to deliver intensive exercise programmes.VR rehabilitation systems need to be designed with measurable progressions through difficulty levels.

Construct Validity of the Upper-Limb Interlimb Coordination Test in Stroke.

BACKGROUND: Coordination impairments are under-evaluated in patients with stroke due to the lack of validated assessments resulting in an unclear relationship between coordination deficits and functional limitations. OBJECTIVE: Determine the construct validity of the new clinical upper-limb (UL) Interlimb Coordination test (ILC2) in individuals with chronic stroke. METHODS: Thirteen individuals with stroke, ≥40 years, with ≥30° isolated supination of the more-affected (MAff) arm, who could understand instructions and 13 healthy controls of similar age participated in a cross-sectional study. Participants performed synchronous bilateral anti-phase forearm rotations for 10 seconds in 4 conditions: self-paced internally-paced (IP1), fast internally-paced (IP2), slow externally-paced (EP1), and fast externally-paced (EP2). Primary (continuous relative phase-CRP, cross-correlation, lag) and secondary outcome measures (UL and trunk kinematics) were compared between groups. RESULTS: Participants with stroke made slower UL movements than controls in all conditions, except EP1. Cross-correlation coefficients were lower (i.e., closer to 0) in stroke in IP1, but CRP and lag were similar between groups. In IP1 and matched-speed conditions (IP1 for healthy and IP2 for stroke), stroke participants used compensatory trunk and shoulder movements. The synchronicity sub-scale and total scores of ILC2 were related to temporal coordination in IP2. Interlimb Coordination test total score was related to greater shoulder rotation of the MAff arm. Interlimb Coordination test scores were not related to clinical scores. CONCLUSION: Interlimb Coordination test is a valid clinical measure that may be used to objectively assess UL interlimb coordination in individuals with chronic stroke. Further reliability testing is needed to determine the clinical utility of the scale.

Reaching performance scale for stroke - Test-retest reliability, measurement error, concurrent and discriminant validity.

INTRODUCTION: Post-stroke upper limb motor improvement can be better quantified by describing movement patterns characterizing movement quality and use of compensations. Movement patterns can be described using both kinematic and clinical outcomes. One clinical outcome that assesses movement quality and compensations used for reaching a Close (18 points) and Far target (18 points) is the Reaching Performance Scale for Stroke (RPSS). OBJECTIVE: To estimate the pilot test-retest reliability and validity (concurrent, discriminant) of the RPSS in individuals with chronic stroke. DESIGN: Retrospective data analysis. SETTING: Research laboratory. PARTICIPANTS: Seventy-two individuals with upper limb hemiparesis ≥6 months prior to participation. INTERVENTION: Not applicable. MAIN OUTCOME MEASURE: RPSS Close and Far Target scores. Intraclass correlation coefficients (ICCs) helped assess pilot test-retest reliability on a subset of 14 participants. Concurrent validity was assessed for individual RPSS items with corresponding kinematic outcomes (trunk displacement, shoulder flexion, shoulder horizontal adduction, elbow extension, trajectory straightness) using Pearson correlations. We also ran multiple regression analyses with the RPSS total scores and used kinematic outcomes as the criterion standard. Logistic regression analyses estimated discriminant validity. We divided participants into two groups based on the Fugl-Meyer Assessment (FMA) scores (mild: ≥50/66; moderate-to-severe: ≤49/66). RESULTS: Test-retest reliability was excellent for Close (ICC = 0.98, 95% confidence interval [CI] 0.94-0.99) and Far targets (ICC = 0.98, 95% CI 0.95-0.99). Individual RPSS items for both targets were mildly to moderately correlated with corresponding kinematic values. A combination of trajectory straightness, elbow extension, and trunk displacement explained the majority of the variance in RPSS scores (47%) for both targets. The RPSS scores discriminated between individuals with mild and moderate-to-severe motor impairment for both Close (ExpB = 3.33, P < .001; 95% CI 1.70-6.52) and Far targets (ExpB = 2.59, P < .001, 95% CI 1.65-4.07). Cutoff points for transition between groups were 15.5 (Close target) and 14 (Far target). CONCLUSION: The RPSS is a valid clinical measure with excellent pilot results of test-retest reliability for assessing movement patterns and compensations used for reaching.

Effect of Object Texture and Weight on Ipsilateral Corticospinal Influences During Bimanual Holding in Humans.

We tested the hypothesis that the ipsilateral corticospinal system, like the contralateral corticospinal system, controls the threshold muscle length at which wrist muscles and the stretch reflex begin to act during holding tasks. Transcranial magnetic stimulation was applied over the right primary motor cortex in 21 healthy subjects holding a smooth or coarse block between the hands. Regardless of the lifting force, motor evoked potentials in right wrist flexors were larger for the smooth block. This result was explained based on experimental evidence that motor actions are controlled by shifting spatial stretch reflex thresholds. Thus, the ipsilateral corticospinal system is involved in threshold position control by modulating facilitatory influences of hand skin afferents on motoneurons of wrist muscles during bimanual object manipulation.

Clinical Motor Coordination Tests in Adult Neurology: A Scoping Review.

Purpose: This scoping review aimed to identify which clinical tests are used to assess upper limb, lower limb, and trunk motor coordination, and their metric and measurement properties for adult neurological populations. Method: MEDLINE (1946-) and EMBASE (1996-) databases were searched using keywords such as movement quality, motor performance, motor coordination, assessment, and psychometrics. Data regarding the body part assessed, neurological condition, psychometric properties, and scored metrics of spatial and/or temporal coordination were independently extracted by two reviewers. Alternate versions of some tests such as the Finger-to-Nose Test were included. Results: Fifty-one included articles yielded 2 tests measuring spatial coordination, 7 tests measuring temporal coordination, and 10 tests measuring both. Scoring metrics and measurement properties differed between tests, with a majority of tests having good-to-excellent measurement properties. Conclusions: The metrics of motor coordination scored by current tests vary. Since tests do not assess functional task performance, the onus falls on clinicians to infer the connection between coordination impairments and functional deficits. Clinical practice would benefit from the development of a battery of tests that assesses the metrics of coordination related to functional performance.

Objectif : la présente revue exploratoire visait à déterminer quels tests cliniques sont utilisés pour évaluer la coordination motrice des membres supérieurs, des membres inférieurs et du tronc, ainsi que pour déterminer leurs propriétés métriques et de mesures dans les populations d'adultes ayant des troubles neurologiques. Méthodologie : les chercheurs ont fouillé les bases de données de MEDLINE (1946­) et d'EMBASE (1996­) au moyen de mots-clés comme movement quality, motor performance, motor coordination, assessment et psychometrics. Deux analystes indépendants ont extrait les données relatives aux parties du corps évaluées, à l'affection neurologique, aux propriétés psychométriques et aux mesures de coordination spatiale ou temporelle calculées. D'autres versions de certains tests, comme l'épreuve doigt-nez, ont été incluses. Résultats : au total, les 51 articles retenus incluaient deux tests qui mesuraient la coordination spatiale, sept tests qui mesuraient la coordination temporelle et dix qui mesuraient ces deux types de coordination. Les mesures calculées et les propriétés de mesure différaient entre les tests, mais les propriétés de la majorité d'entre elles étaient bonnes à excellentes. Conclusions : les mesures de coordination motrice calculées par les tests actuels varient. Puisque les tests n'évaluent pas la performance des tâches fonctionnelles, il revient aux cliniciens d'extrapoler les liens entre les déficits de coordination et les déficits fonctionnels. La création d'une batterie de tests pour évaluer les mesures de coordination liées à la performance fonctionnelle serait bénéfique en pratique clinique.

Central pattern generator and human locomotion in the context of referent control of motor actions.

Unperturbed human locomotion presumably results from feedforward shifts in stable body equilibrium in the environment, thus avoiding falling and subsequent catching considered in alternative theories of locomotion. Such shifts are achieved by relocation of the referent body configuration at which multiple muscle recruitment begins. Rather than being directly specified by a central pattern generator, multiple muscles are activated depending on the extent to which the body is deflected from the referent, threshold body configuration, as confirmed in previous studies. Based on the referent control theory of action and perception, solutions to classical problems in motor control are offered, including the previously unresolved problem of the integration of central and reflex influences on motoneurons and the problem of how posture and movement are related. The speed of locomotion depends on the rate of shifts in the referent body configuration. The transition from walking to running results from increasing the rate of referent shifts. It is emphasised that there is a certain hierarchy between reciprocal and co-activation of agonist and antagonist muscles during locomotion and other motor actions, which is also essential for the understanding of how locomotor speed is regulated. The analysis opens a new avenue in neurophysiological approaches to human locomotion with clinical implications.