Kinematic motion abnormalities and bimanual performance in children with unilateral cerebral palsy.

AIM: To evaluate the relationship between the movement abnormalities of the impaired upper limb in children with unilateral cerebral palsy (CP) and bimanual performance. METHOD: Twenty-three children with unilateral CP (mean age 11y 10mo [SD 2y 8mo]) underwent evaluation of bimanual performance (Assisting Hand Assessment [AHA]) and a three-dimensional movement analysis to measure deviations in the movement of their affected upper limb, and compared with 23 typically developing children (TDC) (mean age 11y 11mo [SD 2y 5mo]). Kinematic indices, such as the Global Arm Profile Score (APS), which summarizes the global movement deviation of the upper limb from the norm, and the Global Arm Variable Score (AVS), which represent movement deviations for a given joint, were calculated and correlated to AHA. RESULTS: Values of kinematic indices were significantly higher in children with unilateral CP than in TDC. A strong correlation between Global-APS and AHA score (r=-0.75) was found. Other significant correlations were found with Global-AVS, especially in distal joints. INTERPRETATION: Children with unilateral CP had more movement deviations than TDC. The global movement deviation of the impaired upper limb was strongly correlated with bimanual performance. The influence of distal abnormalities confirms the importance of considering these limitations in therapeutics. WHAT THIS PAPER ADDS: Children with unilateral cerebral palsy had more movement deviations than typically developing children in unimanual tasks. A strong relationship was found between movement deviations of the impaired upper limb and bimanual performance.

Diagnosis and treatment of anteroinferior capsular redundancy associated with anterior shoulder instability using an open Latarjet procedure and capsulorrhaphy.

PURPOSE: There is a paucity of data detailing management of anterior capsular redundancy (ACR) when using the Latarjet procedure for unidirectional instability. This study aimed to describe the surgical management and to assess the clinical profile of patients presenting with anterior capsular redundancy [ACR(+)] with anterior shoulder instability. METHODS: Seventy-seven patients who had a Latarjet procedure were followed for a 55-month period. Per-operative ACR was assessed during surgery. ACR was considered present if the inferior capsular flap of a Neer T-shaft capsulorrhaphy was able to cover the superior capsular flap with the arm in the neutral position. Patients with ACR(+) received an additional Neer capsulorrhaphy, while patients with ACR(-) did not. This per-operative finding was correlated with demographics, clinical, radiological pre-operative data and surgical outcome. RESULTS: Patients presenting with a per-operative ACR(+) were significantly associated with a sulcus sign (P < 0.001), a Beighton score >4 (P < 0.01), a low-energy instability history (P < 0.05), a predominant history of subluxations (P < 0.05), fewer Hill-Sachs lesion (P < 0.05) and a female gender (P < 0.05), but not significantly with external rotation >85°. Open standard Latarjet procedures with Neer capsulorrhaphy in ACR(+) patients showed excellent or good results and stability rate of 95 %. All patients except four who presented with a new dislocation after surgery were satisfied with their outcome. Thirteen patients (16 %) had a persistent apprehension sign at the last follow-up. ACR(+) and ACR(-) groups did not show significant difference in the mean values of Rowe, Walch-Duplay and Constant-Murley scores. CONCLUSION: ACR correlated with a sulcus sign, Beighton score and instability history. In anterior shoulder instability associated with ACR, the Latarjet procedure with a Neer capsulorrhaphy appears a satisfactory treatment alternative to arthroscopic or open capsular shift. It decreased apprehension in comparison with Latarjet procedures without capsular repair. LEVEL OF EVIDENCE: Cases series, treatment study, Level IV.

Volumetric definition of shoulder range of motion and its correlation with clinical signs of shoulder hyperlaxity. A motion capture study.

BACKGROUND: Shoulder hyperlaxity (SHL) is assessed with clinical signs. Quantification of SHL remains difficult, however, because no quantitative definition has yet been described. With use of a motion capture system (MCS), the aim of this study was to categorize SHL through a volumetric MCS-based definition and to compare this volume with clinical signs used for SHL diagnosis. METHOD: Twenty-three subjects were examined with passive and active measurement of their shoulder range of motion (SROM) and then with an MCS protocol, allowing computation of the shoulder configuration space volume (SCSV). Clinical data of SHL were assessed by the sulcus sign, external rotation with the arm at the side (ER1) >85° in a standing position, external rotation >90° in a lying position, and Beighton score for general joint laxity. Active and passive ER1, EIR2 (sum of external and internal rotation at 90° of abduction), flexion-extension, and abduction were also measured and correlated to SCSV. RESULTS: Except for the sulcus sign, SCSV was significantly correlated with all clinical signs used for SHL. Passive examination of the different SROMs was better correlated to SCSV than active examination. In passive examination, the worst SROM was ER1 (R = 0.36; P = .09), whereas EIR2, flexion, and abduction were highly correlated to SCSV (P < .01). CONCLUSION: SCSV appears to be an appealing tool for evaluation of SHL regarding its correlation with clinical signs used for SHL diagnosis. The sulcus sign and ER1 >85° in a standing position appear less discriminating and should be replaced by EIR2 measurement for SHL diagnosis.

Impairment and characteristics of postural control sub-components in people with COPD: a scoping review.

PURPOSE: Impairment of postural control is common in people with COPD. However, the precise characteristics of this alteration are not clearly known. The "Systems Framework for Postural Control" which define postural control sub-components, represents an interesting tool to explore this field. The main aim of this review was to identify which postural control sub-components are impaired in people with COPD and to summarise characteristics for each sub-component. A secondary aim was to precise the relation between postural control and activities of daily living (ADL). MATERIALS AND METHODS: A scoping review was conducted, according to the JBI methodology. Medline, Cochrane Library, Scielo, Google Scholar, OpenGrey, and HAL were searched from inception to May 2022. The search was performed in English and French. RESULTS: Eighty-nine articles were included. There was evidence of a potential impairment for most of the postural control sub-components. Characteristics of every sub-component alteration were heterogeneous. Reduced postural control could be associated with difficulties in ADL. CONCLUSIONS: People with COPD may have impairment in a wide range of postural control sub-components. Further research is needed to clarify if a common pattern of modification exits for this alteration and to precise the link with ADL.Implications for rehabilitationImpairment of postural control is a common extra-respiratory manifestation in people with COPD and so clinicians must include it in their clinical reasoning.Numerous postural control sub-components could be altered in people with COPD, suggesting that postural control assessment must be holistic.This scoping review shows that characteristics of postural control impairment are varied and that there may be no common pattern at the COPD population level.The relationship between impaired postural control and activities of daily living remains unclear, but clinicians should be alert to potential negative interactions between these two areas.

Characteristics and Predictors of Postural Control Impairment in Patients With COPD Participating in a Pulmonary Rehabilitation Program.

PURPOSE: Postural control impairment has been identified as a potential extrarespiratory manifestation in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to identify clinical factors that characterize patients with reduced postural control, to examine the correlation between clinical factors and postural control and to determine predictors of an impaired postural control among COPD participants enrolled in a pulmonary rehabilitation (PR) program. METHODS: This study is a secondary analysis of an observational study (PARACHUTE). The baseline assessment of the PR program was used for the analysis. Postural control impairment was defined using the Brief BESTest score (BBT). RESULTS: Participants (n = 73) were included in the analysis, 43 of them were classified in the reduced postural control group. The between-group comparison (non-reduced vs reduced postural control) identified differences for partial pressure in oxygen (Pa O2 ), Saint George Respiratory Questionnaire (SGRQ) total score and subscores (SGRQ-Symptoms, SGRQ-Activities, and SGRQ-Impact), COPD assessment test (CAT), and anxiety score of the Hospital Anxiety and Depression Scale. The BBT score was significantly correlated with maximal inspiratory pressure (MIP), SGRQ, SGRQ-Symptoms, SGRQ-Impact, Falls Efficacy Scale, modified Medical Research Council Scale, 6-min walk test, and Pa O2 . Logistic regression identified SGRQ-Symptoms, Pa O2 , MIP, and body mass index (BMI) as predictors of the presence of reduced postural control. CONCLUSION: Low quality of life (QoL) and Pa O2 and high anxiety seem to be discriminative characteristics of patients with COPD with reduced postural control. Furthermore, QoL, Pa O2 , inspiratory muscle strength, and BMI seem to be acceptable predictors of the presence of postural control impairment.

Locomotion behavior of chronic Non-Specific Low Back Pain (cNSLBP) participants while walking through apertures.

BACKGROUND: Chronic Non-Specific Low Back Pain (cNSLBP) has been identified as one of the leading global causes of disability and is characterized by symptoms without clear patho-anatomical origin. The majority of clinical trials assess cNSLBP using scales or questionnaires, reporting an influence of cognitive, emotional and behavioral factors. However, few studies have explored the effect of chronic pain in daily life tasks such as walking and avoiding obstacles, which involves perceptual-motor processes to interact with the environment. RESEARCH QUESTION: Are action strategies in a horizontal aperture crossing paradigm affected by cNSLBP and which factors influence these decisions ? METHODS: 15 asymptomatic adults (AA) and 15 cNSLBP participants walked along a 14 m long path, crossing through apertures ranging from 0.9 to 1.8 times their shoulder width. Their movement was measured using the Qualisys system, and pain perception was evaluated by self-administered questionnaires. RESULTS: The cNSLBP participants stopped rotating their shoulders for a smaller aperture relative to their shoulder width (1.18) than the AA participants (1.33). In addition, these participants walked slower, which gave them more time to make the movement adaptations necessary to cross the aperture. No correlation was found between the variables related to pain perception and the critical point but the levels of pain were low with a small variability. SIGNIFICANCE: This study shows that during a horizontal aperture crossing task requiring shoulder rotation to pass through small apertures, cNSLBP participants appear to exhibit a riskier adaptive strategy than AA participants by minimizing rotations that could induce pain. This task thus makes it possible to discriminate between cNSLBP participants and pain-free participants without measuring the level of pain. The identification number registered in the clinical trials is NCT05337995.

Collision avoidance strategies between two athlete walkers: Understanding impaired avoidance behaviours in athletes with a previous concussion.

BACKGROUND: Individuals who have sustained a concussion often display associated balance control deficits and visuomotor impairments despite being cleared by a physician to return to sport. Such visuomotor impairments can be highlighted in collision avoidance tasks that involves a mutual adaptation between two walkers. However, studies have yet to challenged athletes with a previous concussion during an everyday collision avoidance task, following return to sport. RESEARCH QUESTION: Do athletes with a previous concussion display associated behavioural changes during a 90°-collision avoidance task with an approaching pedestrian? METHODS: Thirteen athletes (ATH; 9 females, 23 ±â€¯4years) and 13 athletes with a previous concussion (CONC; 9 females, 22 ±â€¯3 years, concussion <6 months) walked at a comfortable walking speed along a 12.6 m pathway while avoiding another athlete on a 90º-collision course. Each participant randomly interacted with individuals from the same group 20 times and interacted with individuals from the opposite group 21 times. Minimum predicted distance (mpd) was used to examine collision avoidance behaviours between ATH and CONC groups. RESULTS: The overall progression of mpd(t) did not differ between groups (p > .05). During the collision avoidance task, previously concussed athletes contributed less when passing second compared to their peers(p < .001). When two previously concussed athletes were on a collision course, there was a greater amount of variability resulting in inappropriate adaptive behaviours. SIGNIFICANCE: Although successful at avoiding a collision with an approaching athlete, previously concussed athletes exhibit behavioural changes manifesting in riskier behaviours. The current findings suggest that previously concussed athletes possess behavioural changes even after being cleared to returned to sport, which may increase their risk of a subsequent injury when playing.

Motor patterns of the impaired upper limb in children with unilateral cerebral palsy performing bimanual tasks.

BACKGROUND: Upper limb movement patterns have not yet been identified in bimanual conditions despite the difficulties children with unilateral cerebral palsy have performing bimanual activities. The aim was to identify specific motor patterns from kinematic deviations during bimanual tasks in this population. METHODS: Twenty children with unilateral cerebral palsy and 20 age-matched, typically developing children performed the five tasks of a 3D bimanual protocol. To evaluate upper limb kinematic deviations, 10 Arm Variable Scores were calculated for the affected /non-dominant upper limb of each participant for each task. Sparse K-means cluster analysis was applied to the 50 Arm Variable Scores of all the children to identify motor patterns and determining variables. Clinical tests of impairment (muscle strength, selectivity, spasticity) and function (Assisting hand assessment, Abilhand-Kids) were compared between the clusters obtained. FINDINGS: Three different motor patterns were identified using the data from all the children: mild, proximal-distal and proximal-distal with trunk. The most important cluster determinants were the Arm Variable Scores for pronation-supination and wrist extension. In the cerebral palsy group, scores of impairments (p < .01) and function (Assisting Hand Assessment [p < .001] and Abilhand-Kids [p = .004]) differed for each motor pattern. Supination and wrist extension deviations differed significantly between the groups (p < .001). INTERPRETATION: During performance of bimanual tasks, children with unilateral cerebral palsy used distinct motor patterns that each corresponded to a specific clinical profile. Elbow-wrist deviations were the largest and most decisive and were specific to the cerebral palsy group: they should be the target of interventions to enhance bimanual function. CLINICALTRIALS: gov identifier: NCT03888443.

Inverse relationship between percentage body weight change and finishing time in 643 forty-two-kilometre marathon runners.

OBJECTIVE: The purpose of this study was to determine the relationship between athletic performance and the change in body weight (BW) during a 42 km marathon in a large cohort of runners. METHODS: The study took place during the 2009 Mont Saint-Michel Marathon (France). 643 marathon finishers (560 males and 83 females) were studied. The change in BW during the race was calculated from measurements of each runner's BW immediately before and after the race. RESULTS: BW loss was 2.3 ± 2.2% (mean±SEM) (p<0.01). BW loss was -3.1 ± 1.9% for runners finishing the marathon in less than 3 h; -2.5 ± 2.1% for runners finishing between 3 and 4 h; and -1.8 ± 2.4% for runners who required more than 4 h to complete the marathon. The degree of BW loss was linearly related to 42 km race finishing time (p<0.0000001). Neither age nor gender influenced BW loss during the race. CONCLUSIONS: BW loss during the marathon was inversely related to race finishing time in 643 marathon runners and was >3% in runners completing the race in less than 3 h. These data are not compatible with laboratory-derived data suggesting that BW loss greater than 2% during exercise impairs athletic performance. They match an extensive body of evidence showing that the most successful athletes in marathon and ultra-marathon running and triathlon events are frequently those who lose substantially more than 3-4% BW during competition.

Collision avoidance behaviours between older adult and young adult walkers.

BACKGROUND: Collision avoidance between two walkers requires a mutual adaptation based on visual information in order to be successful. Age-related changes to visuomotor processing, kinesthetic input, and intersegmental dynamics increases the risk of collision and falls in older adults. However, few studies examine behavioural strategies in older adults during collision avoidance tasks with another pedestrian. RESEARCH QUESTION: Is there a difference between older adults' and young adults' collision avoidance behaviours with another pedestrian? METHODS: Seventeen older adults (x¯ = 68 ± 3 years) and seventeen young adults (x¯ = 23 ± 2 years) walked at a comfortable walking speed along a 12.6 m pathway while avoiding another walker. Trials were randomized equally to include 20 interactions with the same age group and 21 interactions with the opposite age group. Minimum predicted distance (mpd) was used to characterize collision avoidance behaviours between older adults and young adults. RESULTS: Older adults had riskier avoidance behaviours, passing closer to the other pedestrian (0.79 m ± 0.18 m) compared to when two young adults were on a collision course (0.93 m ± 0.17 m) (χ²(3) = 35.94, p < .0001). Whenever an older adult was on a collision course with a young adult, the young adult contributed more to the avoidance regardless of passing order. SIGNIFICANCE: The results from the current study highlight age-related effects during a collision avoidance task in older adults resulting in risky behaviour and a potential collision. Future studies should further investigate age-related visuomotor deficits during collision avoidance tasks in cluttered environments using virtual reality in order to tease out factors that contribute most to avoidance behaviours in older adults.

Young and older adult pedestrians' behavior when crossing a street in front of conventional and self-driving cars.

Self-driving vehicles are gradually becoming a reality. But the consequences of introducing such automated vehicles (AVs) into current road traffic cannot be clearly foreseen yet, especially for pedestrian safety. The present study used virtual reality to examine the pedestrians' crossing behavior in front of AVs as compared to conventional cars (CVs). Thirty young (ages 21-39) and 30 older (ages 68-81) adults participated in a simulated street-crossing experiment allowing for a real walk across an experimental two-way street. Participants had to cross (or not cross) in mixed traffic conditions where highly perceptible AVs always stopped to let them cross, while CVs did not brake to give them the right of way. Available time gap (from 1 to 5 s), approach speed (30 or 50 km/h), and the lane in which the cars were approaching (near and/or far lane of the two-way street) were varied. The results revealed a significantly higher propensity to cross the street, at shorter gaps, when AVs gave way to participants in the near lane while CVs were approaching in the far lane, leading to more collisions in this condition than in the others. These risky decisions were observed for both young and older participants, but much more so for the older ones. The results also indicated hesitation to cross in front of an AV in both lanes of the two-way street, with later initiations and longer crossing times, especially for the young participants and when the AVs were approaching at a short distance and braked suddenly. This study highlights the potential risks for pedestrians of introducing AVs into current road traffic, complicating the street-crossing task for young and older people alike. Future studies should look further into the role of repeated practice and trust in AVs. The design of these vehicles must also be addressed. Some practical recommendations are provided.

A new child-friendly 3D bimanual protocol to assess upper limb movement in children with unilateral cerebral palsy: Development and validation.

Unilateral cerebral palsy (uCP) causes upper limb movement disorders that impact on daily activities, especially in bimanual condition. However, a few studies have proposed bimanual tasks for 3D motion analysis. The aim of this study was to validate the new version of a child-friendly, 3D, bimanual protocol for the measurement of joint angles and movement quality variables. Twenty children with uCP and 20 typically developing children (TDC) performed the five-task protocol integrated into a game scenario. Each task specifically targeted one or two upper limb degrees of freedom. Joint angles, smoothness and trajectory straightness were calculated. Elbow extension, supination, wrist extension and adduction amplitudes were reduced; hand trajectories were less smooth and straight in children with uCP compared to TDC. Correlations between the performance-based score and kinematic variables were strong. High within and between-session reliability was found for most joint angle variables and lower reliability was found for smoothness and straightness in most tasks. The results therefore demonstrated the validity and reliability of the new protocol for the objective assessment of bimanual function in children with uCP. The evaluation of both joint angles and movement quality variables should increase understanding of pathological movement patterns and help clinicians to optimize treatment. ClinicalTrials.gov identifier: NCT03888443.

The effects of repetitive neck-muscle vibration on postural disturbances after a chronic stroke.

OBJECTIVE: We aimed to test a repeated program of vibration sessions of the neck muscles (rNMV) on postural disturbances and spatial perception in patients with right (RBD) versus left (LBD) vascular brain damage. METHODS: Thirty-two chronic stroke patients (mean age 60.9±10 yrs and mean time since stroke 4.9±4 yrs), 16 RBD and 16 LBD, underwent a program of 10 sessions of NMV over two weeks. Posturography parameters (weight-bearing asymmetry (WBA), Xm, Ym, and surface), balance rating (Berg Balance Scale (BBS), Timed Up and Go (TUG)), space representation (subjective straight ahead (SSA), longitudinal body axis (LBA), subjective visual vertical (SVV)), and post-stroke deficiencies (motricity index, sensitivity, and spasticity) were tested and the data analyzed by ANOVA or a linear rank-based model, depending on whether the data were normally distributed, with lesion side and time factor (D-15, D0, D15, D21, D45). RESULTS: The ANOVA revealed a significant interaction between lesion side and time for WBA (P<0.0001) with a significant shift towards the paretic lower limb in the RBD patients only (P=0.0001), whereas there was no effect in the LBD patients (P=0.98). Neither group showed a significant modification of spatial representation. Nonetheless, there was a significant improvement in motricity (P=0.02), TUG (P=0.0005), and BBS (P<0.0001) in both groups at the end of treatment and afterwards. CONCLUSIONS: rNMV appeared to correct WBA in RBD patients only. This suggests that rNMV could be effective in treating sustainable imbalance due to spatial cognition disorders.

Assessment of bimanual performance in 3-D movement analysis: Validation of a new clinical protocol in children with unilateral cerebral palsy.

BACKGROUND: The "Be an Airplane Pilot" (BE-API) protocol is a novel 3-D movement analysis (3DMA) protocol assessing the bimanual performance of children during a game. OBJECTIVE: This study aimed to investigate the reliability and validity of this protocol in children with unilateral cerebral palsy (uCP). METHODS: Angular waveforms (WAVE), maximum angles (MAX) and range of motion (ROM) of the trunk, shoulder, elbow and wrist joints were collected in children with uCP and in typically developing children (TDC) during 4 tasks of the BE-API protocol designed to explore specific degrees of freedom (DoF). The inter-trial reliability for children with uCP was assessed with the coefficient of multiple correlation (CMC) for WAVE and the intraclass correlation coefficient (ICC) and standard error of measurement (SEM) for MAX and ROM. Clinical performance-based measures, including the Assisting Hand Assessment (AHA) and ABILHAND-Kids scores, were used to explore correlations between clinical measures and kinematic parameters in children with uCP. RESULTS: 20 children with uCP (13 boys; mean age 12.0 [SD 3.2] years) and 20 TDC (11 boys; mean age 11.9 [SD 3.4] years) were included. In children with uCP, most kinematic parameters showed high reliability (WAVE: CMC≥0.82; MAX and ROM: ICC≥0.85, SEM≤4.7°). Elbow extension, forearm supination, and wrist adduction were reduced and wrist flexion was increased for children with uCP versus TDC (P<0.01). In children with uCP, MAX and ROM values were moderately correlated with clinical assessments (AHA score: r=0.48-0.65; ABILHAND-Kids score: r=0.48-0.49). CONCLUSIONS: The BE-API protocol is a 3DMA-bimanual performance-based assessment that is highly reliable in children with uCP. Children with uCP and TDC significantly differed in some clinically relevant kinematic parameters. The BE-API is a promising playful tool, helpful for better understanding upper-limb motor movement abnormalities in bimanual conditions and for tailoring treatments to individual deficits.

Minimum predicted distance: Applying a common metric to collision avoidance strategies between children and adult walkers.

BACKGROUND: Collision avoidance between two walkers involves a mutual adaptation to speed and orientation in order to successfully avoid a collision. Minimum Predicted Distance (MPD) is the distance at which two walkers would collide if their speed and path trajectory were maintained at first sight of one another. MPD has been used to describe the risk of collision and its evolution over time between two adult walkers when on a collision course. Middle-aged children have been shown to have poor perception-action coupling during static and dynamic collision avoidance tasks. Research has yet to examine whether perception-action coupling deficits persist in a dynamic collision avoidance task involving a child and another walker. RESEARCH QUESTION: Can the metric MPD(t) be used to examine collision avoidance strategies between children and adults? METHODS: Eighteen children (age: 10 ±â€¯1.5 years) and eighteen adults (34 ±â€¯9.6 years) walked along a 12.6 m pathway while avoiding another participant (child or adult). Groups of three children and three adults were recruited per session. Trials were randomized equally such that each adult interacted with another adult 20 times, each child interacted with another child 20 times, and each adult interacted with a child 21 times, for a total of 141 trials. 3D kinematic data of each participant's head was recorded using the Vicon system. RESULTS: The results demonstrated: (1) MPD(t) can be used to predict future collisions in children, (2) MPD(t) is an absolute measure that is consistently lower when a child is involved compared to two adult walkers, (3) the individual passing second, even when it is a child, contributes more to MPD(t) than the walker passing first. SIGNIFICANCE: It appears children have developed adult-like strategies during a collision avoidance task involving two walkers. Body anthropometrics should be considered when determining collision avoidance strategies between children and adults.

Proposal of a new 3D bimanual protocol for children with unilateral cerebral palsy: Reliability in typically developing children.

INTRODUCTION: Quantitative evaluation of upper limb (UL) kinematics in children with unilateral cerebral palsy (uCP) remains challenging for researchers and clinicians, especially during bimanual situations. This study proposed a new 3D bimanual protocol dedicated to children with uCP, called "Be an Airplane Pilot" (BE-API protocol) and assessed its reliability for typically developing children (TDC). METHODS: this protocol is composed of four bimanual tasks that allow the exploration of all degrees of freedom of the hemiplegic/non-dominant UL. Twenty TDC (mean age 11.9 ±â€¯3.4) carried out three protocol sessions. Reliability was investigated through three kinematic parameters: angular waveforms (WAVE) using the coefficient of multiple correlation (CMC), range of motion (RoM) and maximum angles (MAX) both using the intra-class correlation coefficient (ICC) and the standard error of measurement (SEM). RESULTS: A very good reliability was observed for the three kinematic parameters in most cases (WAVE: CMC ≥0.90, RoM & MAX: ICC ≥0.81, SEM ≤5.0°). DISCUSSION: the very good reliability can be partly explained by the high level of rigor of the protocol. Such promising results open the door to validation tests on children with uCP. The BE-API protocol could pretend to support clinical decisions by objectively assessing the efficiency of therapeutics, e.g. injection of botulinic toxin.

Peripheral vascular changes after home-based passive leg cycle exercise training in people with paraplegia: a pilot study.

OBJECTIVE: To determine the hemodynamic adaptations after home-based passive leg cycle exercise training in person with paraplegia. DESIGN: A randomized controlled trial (small cohort). SETTING: University department of physical medicine and rehabilitation. PARTICIPANTS: A volunteer sample of people with paraplegia (N=17). INTERVENTION: Subjects within the experimental group performed 36 passive cycling sessions at home. MAIN OUTCOME MEASURES: Before and after training, we measured heart rate and maximal and minimal femoral artery blood flow velocity at rest and immediately after a 10-minute session of passive cycling by using a quantitative duplex Doppler ultrasound. For each condition, we calculated the mean blood flow velocity and velocity index (VI), used as an indicator of peripheral resistance. RESULTS: At rest, after training, mean blood flow velocity (P=.08) and VI did not differ significantly in the experimental group compared with the pretraining values (nonparametric analysis). However, in this group, the postexercise mean blood flow velocity and VI are respectively increased and decreased after training (P<.05) compared with the pretraining values. No changes were noted in the control group. CONCLUSIONS: Six weeks of home-based passive cycling training have no significant effect on the rest hemodynamic values but increase the hemodynamic response to acute passive cycling exercise.

How do walkers behave when crossing the way of a mobile robot that replicates human interaction rules?

Previous studies showed the existence of implicit interaction rules shared by human walkers when crossing each other. Especially, each walker contributes to the collision avoidance task and the crossing order, as set at the beginning, is preserved along the interaction. This order determines the adaptation strategy: the first arrived increases his/her advance by slightly accelerating and changing his/her heading, whereas the second one slows down and moves in the opposite direction. In this study, we analyzed the behavior of human walkers crossing the trajectory of a mobile robot that was programmed to reproduce this human avoidance strategy. In contrast with a previous study, which showed that humans mostly prefer to give the way to a non-reactive robot, we observed similar behaviors between human-human avoidance and human-robot avoidance when the robot replicates the human interaction rules. We discuss this result in relation with the importance of controlling robots in a human-like way in order to ease their cohabitation with humans.

Collision Avoidance With Multiple Walkers: Sequential or Simultaneous Interactions?

Collision avoidance between multiple walkers, such as pedestrians in a crowd, is based on a reciprocal coupling between the walkers with a continuous loop between perception and action. Such interpersonal coordination has previously been studied in the case of dyadic locomotor interactions. However, when walking through a crowd of people, collision avoidance is not restricted to dyadic interactions. We examined how dyadic avoidance (1 vs. 1) compared to triadic avoidance (1 vs. 2). Additionally, we examined how the dynamics of a passable gap between two walkers affected locomotor interactions. To this end, we manipulated the starting formation of two walkers that formed a potentially pass-able gap for the other walker. We analyzed the interactions in terms of the evolution over time of the Minimal Predicted Distance and the Dynamics of the Gap, which both provide information about what action is afforded (i.e., passing in front/behind and the pass-ability of the gap). Results showed that some triadic interactions invited for sequential interactions, resulting in avoidance strategies comparable with dyadic interactions. However, some formations resulted in simultaneous interactions where the dynamics of the pass-ability of the gap revealed that the coordination strategy emerged over time through the bi-directional interactions between all walkers. Future work should address which circumstances invite for simultaneous and which for sequential interactions between multiple walkers. This study contributed toward understanding how collision is avoided between multiple walkers at the level of the local interactions.

Collision Avoidance Behavior between Walkers: Global and Local Motion Cues.

Daily activities require agents to interact with each other, such as during collision avoidance. The nature of visual information that is used for a collision free interaction requires further understanding. We aim to manipulate the nature of visual information in two forms, global and local information appearances. Sixteen healthy participants navigated towards a target in an immersive computer-assisted virtual environment (CAVE) using a joystick. A moving passive obstacle crossed the participant's trajectory perpendicularly at various pre-defined risks of collision distances. The obstacle was presented with one of five virtual appearances, associated to global motion cues (i.e., a cylinder or a sphere), or local motion cues (i.e., only the legs or the trunk). A full body virtual walker, showing both local and global motion cues, used as a reference condition. The final crossing distance was affected by the global motion appearances, however, appearance had no qualitative effect on motion adaptations. These findings contribute towards further understanding what information people use when interacting with others.