Anouk Lamontagne

McGill University, Montréal, Quebec, Canada

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Publications (61)99.54 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. Whether the collisions occur as a result of attentional-perceptual deficits caused by VSN or due to post-stroke locomotor deficits, is not understood. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Methods: Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30° contralesionally/ ipsilesionally. Results: Greater detection times were observed for contralesional or head-on obstacle approaches, while collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. Conclusion: The observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentional-perceptual deficits due to VSN, independent of post-stroke locomotor deficits, alters obstacle avoidance abilities.
    IEEE Transactions on Neural Systems and Rehabilitation Engineering 12/2014; · 3.26 Impact Factor
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    ABSTRACT: Dual-tasking that involves the performance of a cognitive task while walking can be challenging for post-stroke individuals. The presence of an attentional disorder such as visuospatial neglect (VSN) may further compromise the performance on the cognitive task, locomotor task or both. We observed the differences between participants with and without VSN on the ability to avoid moving obstacles while walking and performing a cognitive task. Methods: Three post-stroke participants- two with VSN (V1, V2) and one without VSN (S1) were assessed in a virtual environment consisting of a target and three obstacles located head-on (HO) and 30° contralesionally (CL) and ipsilesionally (IL). Participants were instructed to walk towards the target while avoiding the obstacle that randomly approached from one of the three directions. A simple pitch-identification task was used as a cognitive task. 3 tasks were performed a) a seated- cognitive task b) walking task alone and c) walking with cognitive task. We compared rates of cognitive error, the collision rates (CR), walking speeds and minimum distances from the obstacle between the cognitive alone /walking alone- single task (ST), and walking with cognitive task- dual task (DT) conditions. Results: No participant showed errors on the cognitive alone task. During the walking task, participant S1 showed collisions with HO obstacle during both the ST (CR= 40%) and DT condition (CR=40%) with no errors on the cognitive task. During the DT condition, however, participant S1 maintained larger minimum distances from obstacles as well as faster walking speeds for all three obstacle conditions, compared to the ST. Participant V1 showed no collisions during the ST but collided with CL (CR= 50%) and HO (CR= 20%) obstacles during the DT. Participant V2 showed collisions with CL obstacle during the ST and DT condition (CR=50%). Both V1 and V2 showed errors in the cognitive task during the DT condition for all three obstacle approaches (range= 20-100% of trials). V1 and V2 also maintained slower walking speeds and smaller minimum distances for all three obstacle approaches during the DT compared to the ST. Discussion: In the participant without VSN, addition of a simple dual task did not result in worsening of collision rates. Participants with VSN, however, demonstrated deterioration in cognitive or both locomotor & cognitive performance during the DT condition. These preliminary results suggest that the addition of a simple cognitive task may burden the attentional resources in VSN resulting in worsening of task performance. Deterioration in obstacle avoidance performance may compromise safety while walking in the presence of moving objects.
    Society for Neurosciences, 2014, Washington DC; 11/2014
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    ABSTRACT: Nous présentons un projet stratégique multidisciplinaire et multisectoriel mené par le Centre de recherche interdisciplinaire en réadaptation (CRIR), en collaboration avec un centre commercial montréalais, des organismes communautaires et des partenaires de recherche et industriels locaux, nationaux et internationaux. Depuis 2011 ayant le Centre commercial comme laboratoire vivant, plus de 45 projets ont été amorcés pour : (1) identifier les obstacles et facilitateurs environnementaux, physiques et sociaux à la participation ; (2) développer des technologies et interventions pour optimiser la fonction physique et cognitive ; (3) implanter et évaluer l’impact des technologies et interventions in vivo. Deux ans plus tard, avec une approche recherche action participative (RAP) dans le cadre de la Classification International du Fonctionnement, du handicap et de la santé (CIF) de l’OMS, nous discutons des défis et entreprises futures. Les défis incluent la création et le maintien de partenariats, assurant une approche RAP pour engager plusieurs parties prenantes (ex. personnes avec incapacités, chercheurs, professionnels de la santé, membres de la communauté et parties prenantes du centre commercial) et évaluant l’impact global du projet. Les entreprises futures, qui incluent mettre en lien les résultats de recherche avec les recommandations pour les rénovations du centre commercial, sont aussi présentées.
    Alter - European Journal of Disability Research/Revue Européenne de Recherche sur le Handicap 08/2014;
  • Gayatri Aravind, Anouk Lamontagne
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    ABSTRACT: Post-stroke sensorimotor impairments can lead to altered ability to control locomotor heading and avoid obstacles while walking. The presence of visuospatial neglect (VSN) may further hamper the control of walking trajectories due to impairments in the uptake & utilisation of visual information from the contralesional side of space. We examined how participants with post-stroke VSN control their heading to avoid collisions in response to moving obstacles while walking in a virtual environment(VE). Methods: Twelve post-stroke VSN subjects were tested in a VE consisting of a target & 3 obstacles, one of which randomly approached from head-on or 30° to the contralesional/ipsilesional side including control trials with no obstacles. Participants walk towards the target while avoiding a collision with the obstacle..We examined the spatial relationships (heading, heading onsets) maintained by the participants in space and in relation to the obstacle and target. Results: The participants showed a preference to deviate towards the ipsilesional side (positive values) for all four obstacle conditions (from 9.0°±4.2 to 9.9°±5.9; mean±1SD). Subjects also showed preference to rotate their heads ipsilesionally for head-on(11.5°± 9.4), ipsilesional(6.4°±6.1) contralesional obstacle approaches(12.4°±6.6) and control trials(9.2°±6.1). The ipsilesional head rotation and deviation of trajectory continued to be observed even after the obstacle passed the subject. Five participants collided with the contralesional obstacle while eight collided with the head on obstacle. Contralesional colliders showed larger heading reorientations(12.2°±3.8) compared non-colliders(6.6°±4.1), whereas head-on colliders obstacles showed smaller heading reorientations (9.6°±6.9) compared to non-colliders (11.2°±5.7). The colliders also showed delayed onsets of heading reorientation compared to non-colliders for both contralesional (2.6 s±0.5 vs. 2.2 s±0.6) & head-on (4.7s±1.6 vs. 4.0±1.6) obstacles. Discussion: The persistence to veer and reorient the head towards the ipsilesional side is consistent with ipsilesional bias commonly observed in VSN[1] and contrast with the behaviour of healthy individuals reported in a previous study where deviation was observed to occur in the direction opposite to the obstacle approach[2]. The delayed initiation of heading reorientation observed in the colliders may have translated into reduced time and distance available to execute an avoidance strategy. Additionally, the smaller heading reorientation in colliders with head-on obstacles may have kept the participants in the path of collisions, while the larger heading reorientation observed in contralesional colliders may have been an attempt to compensate for the delay in onset of reorientation. Conclusion: Persons with post-stoke VSN collide with obstacles approaching from the contralesional side and from head-on. Control of heading could be a determinant in the risk of collision with moving obstacles.
    International Society of Posture and Gait Research, 2014 (ISPGR), Vancouver, Canada; 06/2014
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    ABSTRACT: Background: Spatial navigation in the presence of dynamic obstacles involves executing locomotor strategies to avoid collisions while navigating towards the goal. The dynamic interaction between a moving person and a moving obstacle can be expressed using the classical differential games approach, whereby subjects’ navigational strategies are shaped largely under the influence of the obstacle until the possibility of a collision is negated. Further, the choice of a circumvention strategy can depend on the degree of influence exerted by the obstacle. The objective of this work is to explore the effect of changing the strength of obstacle influence on navigational strategies used for obstacle avoidance. Methods: The differential games model was based upon an experimental set-up that involved subjects walking in a virtual environment towards a central blue target while avoiding obstacles that randomly approached the subjects from head-on or from 30° left and right. For this work, both subject and the obstacle are assumed to move in a 6mx6m space at a speed of 0.5 m/s. The obstacle influence was modelled by a Gaussian 2D distribution with constant amplitude and flexible elliptical horizontal cross-sections. The elliptical cross-section was oriented such that the longer diameter lay along the direction of obstacle motion. The effect of changing the ratio of longer to shorter diameters from 1.2/0.4 to 1.1/0.4 on obstacle circumvention behavior was simulated. Results: In the simulation, the movement of the subject was similar to the mechanical movement of a heavy ball in a gravitational field on an uneven surface. The subject chose the path with lowest resistance to avoid the obstacle and reach the target. The nature of the avoidance strategy was dependent upon the strength of obstacle influence which was in turn dependent on the size of its horizontal cross-section. With changes in the horizontal cross-section, circumvention behaviours also underwent consequent changes. A longer to shorter diameter ratio of 1.1/0.4 enabled the subject to avoid the obstacle by passing in front of it. A small increase in this ratio to 1.2/0.4 forced a change in the avoidance strategy with the subject now avoiding the obstacle by passing behind it. Thus a small change in the obstacle influence could affect substantial changes in the obstacle avoidance behaviours. Conclusions: In a mathematical simulation of obstacle avoidance based on differential games, a change in the strength of obstacle influence causes consequent changes in avoidance behaviors. The strength of this influence may be related to the characteristics of the obstacle (speed, direction of motion etc.) or the subject’s perception of their capabilities (ability to generate appropriate and sudden changes to gait speed or trajectory). This approach will be further used to formulate obstacle influence parameters using experimental data.
    International Society of Posture and Gait Research, Vancouver, BC, Canada; 06/2014
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    ABSTRACT: Through the lens of a Rehabilitation Living Lab, this paper presents what happens when researchers work with managers and users in the design situation of an urban commercial complex. This multi-sectorial and interdisciplinary research project brings together over 45 researchers to explore issues of social inclusion and social participation of people with disabilities, as they arrive and use the shopping complex. Within the context of a Living Lab, researchers implement various research projects from diverse research paradigms and methodological perspectives. While the research method for the overarching project is within the general framework of participatory action research, all researchers use clinical, basic and experimental forms of research (Friedman, 2003) to move forward the goals and research streams defined at the outset. The research is supported by a parallel design activity with students in a baccalaureate design studio. The overall research project goals and an example of a pilot project are presented in concert with a design studio activity, to consider potential concepts that are research-informed. Discussion of results reveals salient issues that emerge in early findings in pilot studies, and underscores what happens when people from diverse research perspectives work together.
    DRS 2014 International Conference of the Design Research Society, Umea, Sweden; 05/2014
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    Gayatri Aravind, Anouk Lamontagne
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    ABSTRACT: For safe ambulation in the community, detection and avoidance of static and moving obstacles is necessary. Such abilities may be compromised by the presence of visuospatial neglect (VSN), especially when the obstacles are present in the neglected, i.e. contralesional field. Twelve participants with VSN were tested in a virtual environment (VE) for their ability to a) detect moving obstacles (perceptuo-motor task) using a joystick with their non-paretic hand, and b) avoid collision (locomotor task) with moving obstacles while walking in the VE. The responses of the participants to obstacles approaching on the contralesional side and from head-on were compared to those during ipsilesional approaches. Up to 67 percent of participants (8 out of 12) collided with either contralesional or head-on obstacles or both. Delay in detection (perceptuo-motor task) and execution of avoidance strategies, and smaller distances from obstacles (locomotor task) were observed for colliders compared to non-colliders. Participants' performance on the locomotor task was not explained by clinical measures of VSN but slower walkers displayed fewer collisions. Persons with VSN are at the risk of colliding with dynamic obstacles approaching from the contralesional side and from head-on. Locomotor-specific assessments of navigational abilities are needed to appreciate the recovery achieved or challenges faced by persons with VSN.
    Journal of NeuroEngineering and Rehabilitation 03/2014; 11(1):38. · 2.57 Impact Factor
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    Myriam Villeneuve, Virginia Penhune, Anouk Lamontagne
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    ABSTRACT: Music-supported therapy was shown to induce improvements in motor skills in stroke survivors. Whether all stroke individuals respond similarly to the intervention and whether gains can be maintained over time remain unknown. We estimated the immediate and retention effects of a piano training program on upper extremity function in persons with chronic stroke.
    Frontiers in Human Neuroscience 01/2014; 8:662. · 2.91 Impact Factor
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    ABSTRACT: Many falls in older adults occur during walking following trips. Following a trip, older adults take longer than younger adults to recover steady-state walking. Although faster gait speed may improve interlimb coordination, it may also increase fall risk in older adults. We hypothesized that older adults would take longer than younger adults to recover from an unexpected perturbation during gait especially when walking faster. Twelve younger (26.3±4.4 years) and 12 older adults (68.5±3.4 years) walked at comfortable, faster and slower speeds when movement of the dominant leg was unexpectedly arrested for 250ms at 20% swing length. Gait stability was evaluated using the short- and longer-term response to perturbation. In both groups, walking faster diminished the occurrence of elevation and increased that of leg lowering. Older adults took longer than younger adults to recover steady-state walking at all speeds (3.36±0.11 vs. 2.89±0.08 strides) but longer-term recovery of gait stability was not related to gait speed. Arm-leg and inter-arm coordination improved with increasing gait speed in both groups, but older adults had weaker inter-leg coupling following perturbation at all speeds. Although both younger and older adults used speed appropriate responses immediately following perturbation, longer duration of recovery of steady-state walking in older adults may increase fall risk in uncontrolled situations, regardless of gait speed. Recovery from perturbation when walking faster was associated with better interlimb coordination, but not with better gait stability. This indicates that interlimb coordination and gait stability may be distinct features of locomotion.
    Gait & posture 08/2013; · 2.58 Impact Factor
  • IASDR 2013 International Conference Consilience and Innovation in Design, Tokyo, Japan; 08/2013
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    Ala S Aburub, Anouk Lamontagne
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    ABSTRACT: Individuals who have sustained a stroke can manifest altered locomotor steering behaviors when exposed to optic flows expanding from different locations. Whether these alterations persist in the presence of a visible goal and whether they can be explained by the presence of a perceptuo-motor disorder remain unknown. The purpose of this study was to compare stroke participants and healthy participants on their ability to control heading while exposed to changing optic flows and target locations. Ten participants with stroke (55.6 +/- 9.3 yrs) and ten healthy controls (57.0 +/- 11.5 yrs) participated in a mouse-driven steering task (perceptuo-motor task) while seated and in a walking steering task. In the seated steering task, participants were instructed to head or 'walk' toward a target in the virtual environment by using a mouse while wearing a helmet-mounted display (HMD). In the walking task, participants performed a similar steering task in the same virtual environment while walking overground at their comfortable speed. For both experiments, the target and/or the focus of expansion (FOE) of the optic flow shifted to the side (+/-20[degree sign]) or remained centered. The main outcome measure was net heading errors (NHE). Secondary outcomes included mediolateral displacement, horizontal head orientation, and onsets of heading and head reorientation. In the walking steering task, the presence of FOE shifts modulated the extent and timing of mediolateral displacement and head rotation changes, as well as NHE magnitudes. Participants overshot and undershot their net heading, respectively, in response to ipsilateral and contralateral FOE and target shifts. Stroke participants made larger NHEs, especially when the FOE was shifted towards the non-paretic side. In the seated steering task, similar NHEs were observed between stroke and healthy participants. The findings highlight the fine coordination between rotational and translational steering mechanisms in presence of targets and FOE shifts. The altered performance of stroke participants in walking but not in the seated steering task suggests that an altered perceptuo-motor processing of optic flow is not a main contributing factor and that other stroke-related sensorimotor deficits are involved.
    Journal of NeuroEngineering and Rehabilitation 07/2013; 10(1):80. · 2.57 Impact Factor
  • International Conference on Disability and Diversity, Honolulu, Hawaii; 04/2013
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    Myriam Villeneuve, Anouk Lamontagne
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    ABSTRACT: Music-supported therapy (MST) is an innovative approach that was shown to improve manual dexterity in acute stroke survivors. The feasibility of such intervention in chronic stroke survivors and its longer-term benefits, however, remain unknown. The objective of this pilot study was to estimate the short- and long-term effects of a 3-week piano training program on upper extremity function in persons with chronic stroke. A multiple pre-post sequential design was used, with measurements taken at baseline (week0, week3), prior to (week6) and after the intervention (week9), and at 3-week follow-up (week12). Three persons with stroke participated in the 3-week piano training program that combined structured piano lessons to home practice program. The songs, played on an electronic keyboard, involved all 5 digits of the affected hand and were displayed using a user-friendly MIDI program. After intervention, all the three participants showed improvements in their fine (nine hole peg test) and gross (box and block test) manual dexterity, as well as in the functional use of the upper extremity (Jebsen hand function test). Improvements were maintained at follow-up. These preliminary results support the feasibility of using an MST approach that combines structured lessons to home practice to improve upper extremity function in chronic stroke.
    Stroke research and treatment. 01/2013; 2013:159105.
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    ABSTRACT: Individuals with stroke demonstrate deficits in community ambulation, which may be related to deficits in obstacle avoidance. We have devised a VR paradigm to assess locomotor strategies for obstacle circumvention. Four individuals with chronic stroke and four healthy controls walked towards a target while in the presence of a moving obstacle. Dynamic clearance from the obstacle was smaller among people with stroke for a head-on obstacle approach, while it was larger than the control group for diagonal obstacle approaches. This can be attributed to different locomotor adjustments required for each obstacle approach direction and perceptuo-motor impairments in people with stroke.
    Virtual Rehabilitation (ICVR), 2013 International Conference on; 01/2013
  • G. Aravind, A. Lamontagne
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    ABSTRACT: Persons with visuospatial neglect are at risk of colliding with objects while walking due to their inattention to the contralesional space. Twelve participants were assessed on their ability to avoid moving obstacles while walking. Collisions were observed for head-on and contralesionally approaching obstacles, but not for ipsilesional ones. Participants showed delayed responses and maintained smaller distances from contralesional obstacles compared to other approaches. Collisions with head-on vs. contralesional obstacles appeared to depend on walking speed. It is suggested that persons with visuospatial neglect are at risk of colliding with moving obstacles due to contribution of both perceptual and locomotor factors.
    Virtual Rehabilitation (ICVR), 2013 International Conference on; 01/2013
  • A. Liu, J. Fung, A. Lamontagne, R. Hoge, J. Doyon
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    ABSTRACT: Steering using optic flow allows adapting locomotion to the environment. Persons with brain lesions display difficulty steering and thus, gaining insight into the brain regions involved in steering may shed light on the disturbed mechanisms of visuomotor control. A joystick-based navigation task in a virtual environment was used to explore brain regions involved in steering control while exposed to optic flows of changing directions. Functional magnetic resonance imaging revealed that hMT+, bilateral cerebellum, frontal and supplementary eye fields are specifically involved in steering control and may reflect the pathway in which visual motion information is transformed into goal-directed action.
    Virtual Rehabilitation (ICVR), 2013 International Conference on; 01/2013
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    ABSTRACT: BACKGROUND AND PURPOSE:: Decreased walking speed after stroke may be related to changes in temporal and distance gait factors, endurance, and balance. Functional gait deficits may also be related to changes in coordination, specifically between transverse (yaw) plane trunk movements. Our aim was to determine the relationship between intersegmental coordination during gait and functional gait and balance deficits in individuals with stroke. METHODS:: Eleven individuals with chronic stroke and 11 age-matched subjects without disability participated in 2 sessions. In Session 1, clinical evaluations of trunk/limb impairment (Chedoke-McMaster Stroke Assessment), functional gait (Functional Gait Assessment), and balance (BesTest) were performed. In Session 2, gait kinematics during eight 30-second walking trials on a self-paced treadmill at 2 speeds (comfortable and equivalent) were recorded. Equivalence of walking speeds was obtained by asking subjects without disability to walk approximately 20% slower and subjects with stroke to walk approximately 20% faster than their comfortable speed. Thorax and pelvis 3-dimensional angular ranges of motion (ROMs) and intersegmental coordination using the continuous relative phase were analyzed. RESULTS:: Comfortable walking speed was slower in subjects with stroke (0.78 m/s) than in subjects without disability (1.22 m/s), despite matched cadences. At both comfortable and equivalent walking speeds (0.97-0.98 m/s), participants with stroke used more thoracic ROM than pelvic transverse ROM in comparison with subjects without disability. Transverse thorax-pelvis coordination was similar between groups when walking speeds were equivalent, but there was more in-phase coordination in participants with stroke walking at their comfortable, slower speed. In subjects with stroke, thoracic ROM and continuous relative phase were correlated with several clinical functional gait and balance measures. DISCUSSION AND CONCLUSION:: Changes in segmental transverse ROM and coordination were associated with poor gait and with balance abilities in individuals with stroke. Interventions focusing on recovery of these movement characteristics may lead to better clinical outcomes.
    Journal of neurologic physical therapy: JNPT 10/2012; · 1.65 Impact Factor
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    ABSTRACT: Falls during walking are a major cause of injury in post-stroke individuals, and walking faster may further decrease gait stability. We compared gait stability between high-functioning post-stroke individuals and controls at matched speeds. We also evaluated the effect of a speed increase on gait stability in post-stroke individuals. Ten stroke subjects and 10 age-matched controls walked on a self-paced treadmill at matched speeds. Stroke subjects also walked 20% faster than comfortable. Movement of the non-paretic (stroke) or dominant leg (controls) was arrested unexpectedly at 20% of swing. Stroke subjects typically lowered the perturbed leg following perturbation (58% of cases) while controls maintained the leg in the air (49% of cases; p<0.01). In post-stroke subjects, double-support duration was restored later than in controls (4.6±0.8 versus 3.2±0.3 strides; p<0.007). Stroke subjects had larger long-term phase shifts of arm and leg movements, which were less coordinated on the paretic side. A moderate speed increase (~20%) did not influence gait stability or interlimb coupling. However, clinical impairment was related to recovery from perturbation at faster speed. Faster walkers among stroke subjects had better non-paretic arm-leg coupling but were not more stable. Our results suggest that long-term phase resetting of gait involves a high level of motor control that regulates translation of the body in the environment. Impaired descending control following a brain lesion decreases the ability of the motor system to recover from perturbations and to regulate interlimb phase relationships. However, interlimb coordination may not be a major factor in recovery from gait perturbation.
    Journal of Neurophysiology 10/2012; · 3.30 Impact Factor
  • Society for Neuroscience, New Orleans, USA; 08/2012
  • 1st Joint World Congress of the International Society of Posture and Gait Research and Gait and Mental Function, Trondheim, Norway; 06/2012

Publication Stats

652 Citations
99.54 Total Impact Points

Institutions

  • 2001–2014
    • McGill University
      • School of Physical and Occupational Therapy
      Montréal, Quebec, Canada
  • 2011
    • Université de Montréal
      • Department of Physiology
      Montréal, Quebec, Canada
  • 1997–2002
    • Laval University
      • • Faculté de Médecine
      • • Département de Réadaptation
      Québec, Quebec, Canada
    • Institut de réadaptation en déficience physique de Québec
      Québec, Quebec, Canada