Biomedical subjects

Francine Malouin

Publications and source records attributed to Francine Malouin.

18 recordsLinked to original sources

PubMed2006

The effect of foot position and chair height on the asymmetry of vertical forces during sit-to-stand and stand-to-sit tasks in individuals with hemiparesis.

BACKGROUND: The asymmetrical motor pattern of persons with hemiparesis influences the performance of activities that require interactions between the two sides of the body. METHODS: Twelve subjects with a chronic hemiparesis were asked to stand up and sit down at their natural speed in the following foot positions: (1) spontaneous; (2) symmetrical; (3) asymmetrical with the affected foot placed backward; and (4) asymmetrical with the unaffected foot placed backward. Forces were recorded under each foot using two force plates and under each thigh with an instrumented chair. Each foot position was tested at two chair heights corresponding to 100% and 120% of leg length. For each condition, the duration and the asymmetry of loading expressed by the vertical forces were calculated for four different events: onset, transition (forces under feet and thighs), seat-off or seat-on and at the end of the task. FINDINGS: The time to execute the tasks ranged from 2.31 s to 3.69 s with higher values observed for the stand-to-sit task than for the sit-to-stand task. Overall, the asymmetry of vertical forces was greatest in the middle part of the tasks and was not influenced by the chair height. When the subjects were still in contact with the seat, the loading asymmetry originated from a difference between sides at both the thigh and the foot. The asymmetrical foot position with the affected foot backward promoted loading on the affected side during both tasks. Interpretation. This study shows that loading asymmetry was present before seat-off and after seat-on in sit-to-stand and stand-to-sit tasks, respectively. It shows that positioning the affected foot behind reduces the asymmetry whereas positioning the unaffected foot behind increases the asymmetry. Foot position should be taken into consideration when clinicians assess or train for these mobility tasks.

Acceleration↗

PubMed2006

A treadmill and motion coupled virtual reality system for gait training post-stroke.

A virtual reality (VR)-based locomotor training system has been developed for gait rehabilitation post-stroke. The system consists of a self-paced treadmill mounted onto a 6-degrees-of-freedom motion platform. Virtual environments (VEs) that are synchronized with the speed of the treadmill and the motions of the platform are rear-projected onto a screen in front of the walking subject. A feasibility study was conducted to test the capability of two stroke patients and one healthy control to be trained with the system. Three VE scenarios (corridor walking, street crossing, and park stroll) were woven into a gait-training program that provided three levels of complexity (walking speed, slopes, collision avoidances), progression criteria (number of successful trials) and knowledge of results. Results show that, with practice, patients can effectively increase their gait speed as demanded by the task and adapt their gait with respect to the change in physical terrain. However, successful completion of tasks requiring adaptation to increasing demands related to speed and physical terrains does not necessarily predict the patient's ability to anticipate and avoid collision with obstacles during walking. This feasibility study demonstrates that persons with stroke are able to adapt to this novel VR system and be immersed in the VEs for gait training.

Computer Simulation↗

PubMed2004

Bilateral slowing of mentally simulated actions after stroke.

The ability to mentally simulate motor actions was studied in 25 patients with stroke. The duration of imagined and executed movements of the arm and leg was compared. Both executed and imagined movements took longer with the affected limbs than with the unaffected limbs. For both tasks, the duration of movements with the unaffected limbs was longer in the imagined than in the executed conditions, indicating a lack of temporal congruence on that side. Because the temporal uncoupling was found in the limbs contralateral to the intact hemisphere, we propose that this reflects a general slowing in motor imagery that is an indirect consequence of the lesion, rather than a deficit in movement representation within the unaffected hemisphere per se.

Aged↗

PubMed2004

Working memory and mental practice outcomes after stroke.

OBJECTIVE: To examine the relationship between working memory and motor improvement obtained after a single training session combining mental and physical practice. DESIGN: Before-after trial. SETTING: Laboratory of a university-affiliated research rehabilitation center. PARTICIPANTS: A sample of 12 patients with stroke and 14 age- and gender-matched healthy subjects. INTERVENTION: In a single session, patients were trained with combined mental and physical practice to increase the loading on the affected leg while standing up and sitting down. MAIN OUTCOME MEASURES: Motor improvement as measured by the percentage change in limb loading on the affected limb after training and 24 hours later (follow-up), and the relationship between working memory and percentage motor improvement. RESULTS: The loading on the affected leg was improved after training (P< .01) and at follow-up (P< .05), and working memory scores at follow-up correlated significantly (P< .004 to P< .007) with the level of improvement. The visuospatial domain yielded the strongest correlation (r= .83), followed by the verbal (r= .62) and kinesthetic (r= .59) domains. CONCLUSIONS: These results suggest that the outcome (improved limb loading) of mental rehearsal with motor imagery depends on the ability to maintain and manipulate information in working memory.

Adult↗

PubMed2004

The efficacy of combined physical and mental practice in the learning of a foot-sequence task after stroke: a case report.

OBJECTIVE: To investigate the effect of mental practice on the learning of a sequential task for the lower limb in a patient with a hemiparesis resulting from a stroke. DESIGN: A single-case study. SETTING: Research laboratory of a university-affiliated rehabilitation center. PATIENT: A right-handed 38-year-old man who had suffered a left hemorrhagic subcortical stroke 4 months prior. INTERVENTION: The patient practiced a serial response time task with the lower limb in 3 distinct training phases over a period of 5 weeks: 2 weeks of physical practice, 1 week of combined physical and mental practice, and then 2 weeks of mental practice alone. MAIN OUTCOME MEASURES: Performance on the task measured through errors and response times. Imagery abilities measured through questionnaires. RESULTS: The patient's average response time improved significantly during the 1st 5 days of physical practice (26%) but then failed to show further improvement during the following week of physical practice. The combination of mental and physical practice during the 3rd week yielded additional improvement (10.3%), whereas the following 2 weeks of mental practice resulted in a marginal increase in performance (2.2%). CONCLUSION: The findings show that mental practice, when combined with physical practice, can improve the performance of a sequential motor skill in people who had a stroke, and suggest that mental practice could play a role in the retention of newly acquired abilities.

Adult↗

PubMed2004

Training mobility tasks after stroke with combined mental and physical practice: a feasibility study.

This study examines the potential of using mental practice (MP) to promote the learning of 2 mobility tasks in persons with stroke. Twelve patients were trained with MP to increase the loading of the affected limb while standing up from a chair and sitting down. Vertical forces were recorded using force plates under each foot and the chair. Changes in the loading of the affected limb and in task duration, immediately after 1 training session and 24 h later, served as outcomes. After training, the loading of the affected limb had increased (P < 0.001) during standing up (16.2%) and sitting down (17.9%), and the improvement remained significant 24 h later, indicating a learning effect. In contrast, the duration of the performance did not change with training. The results indicate that, in the early stage of learning with MP, changes in limb-loading strategies are a more sensitive measure of performance than is speed.

Adult↗

PubMed2004

The role of technology in task-oriented training in persons with subacute stroke: a randomized controlled trial.

This trial compares the effects of task-oriented physical therapy (PT) provided with and without the use of rehabilitation technology on locomotor recovery in 63 persons with subacute stroke. Participants in the experimental (EXP) group used a treadmill, a Kinetron isokinetic exerciser, and a limb-load monitor, whereas those in the control (CTL) group did not while engaging in PT 1 h per day, 5 days per week for 2 months. Locomotor recovery was assessed by clinical (gait speed, Fugl Meyer motor leg and arm subscores, the Balance Scale, the Timed Up and Go, and the Barthel ambulation subscore) and laboratory outcomes (gait kinematics and kinetics) pre- and posttherapy and 3 months later. Within groups, gait speed (P < 0.01) and all secondary measures improved posttherapy (P < 0.01-0.05), and improvements in clinical measures were maintained at follow-up, but there was no difference between groups (P > 0.05). When the groups were pooled, the increase in gait speed was associated (r = 0.52, P = 0.003) with an increase in ankle power generation of the affected leg. The results demonstrate that the efficacy of the task-oriented approach is not dependent on rehabilitation technology.

Aged↗

PubMed2003

Brain activations during motor imagery of locomotor-related tasks: a PET study.

Positron emission tomography (PET) was used to study the involvement of supraspinal structures in human locomotion. Six right-handed adults were scanned in four conditions while imagining locomotor-related tasks in the first person perspective: Standing (S), Initiating gait (IG), Walking (W) and Walking with obstacles (WO). When these conditions were compared to a rest (control) condition to identify the neural structures involved in the imagination of locomotor-related tasks, the results revealed a common pattern of activations, which included the dorsal premotor cortex and precuneus bilaterally, the left dorsolateral prefrontal cortex, the left inferior parietal lobule, and the right posterior cingulate cortex. Additional areas involving the pre-supplementary motor area (pre-SMA), the precentral gyrus, were activated during conditions that required the imagery of locomotor movements. Further subtractions between the different locomotor conditions were then carried out to determine the cerebral regions associated with the simulation of increasingly complex locomotor functions. These analyses revealed increases in rCBF activity in the left cuneus and left caudate when the W condition was compared to the IG condition, suggesting that the basal ganglia plays a role in locomotor movements that are automatic in nature. Finally, subtraction of the W from the WO condition yielded increases in activity in the precuneus bilaterally, the left SMA, the right parietal inferior cortex and the left parahippocampal gyrus. Altogether, the present findings suggest that higher brain centers become progressively engaged when demands of locomotor tasks require increasing cognitive and sensory information processing.

Adult↗

PubMed2003

Functional cerebral reorganization following motor sequence learning through mental practice with motor imagery.

The goal of the present study was to examine, via positron emission tomography, the functional changes associated with the learning of a sequence of foot movements through mental practice with motor imagery (MI). Following intensive MI training over several days, which led to a modest but significant improvement in performance, healthy subjects showed an increase in activity restricted to the medial aspect of the orbitofrontal cortex (OFC), and a decrease in the cerebellum. These main results are largely consistent with those found in a previous study of sequence learning performed in our laboratory after physical practice of the same task [NeuroImage 16 (2002) 142]. Further analyses showed a positive correlation between the blood flow increase in the OFC and the percentage of improvement on the foot sequence task. Moreover, the increased involvement of the medial OFC revealed a modality specific anatomo-functional organization, as imagination of the sequential task after MI practice activated a more posterior region than its execution. These results demonstrate that learning a sequential motor task through motor imagery practice produces cerebral functional changes similar to those observed after physical practice of the same task. Moreover, the findings are in accord with the hypothesis that mental practice with MI, at least initially, improves performance by acting on the preparation and anticipation of movements rather than on execution per se.

Adult↗

PubMed2003

[New perspectives of locomotor rehabilitation after stroke].

The task-oriented approach incorporating treadmill walking for retraining gait early after stroke has contributed to promote locomotor recovery. To augment practice, training strategies such as mental practice and training in virtual environments are proposed. While the former offers more practice with less physical exertion, the latter allows safe practice in a variety of challenging environments. Work is under way to assess whether these new strategies can further enhance locomotor recovery.

Gait↗

PubMed2003

Comparison of changes in upper and lower extremity impairments and disabilities after stroke.

The aims of this study were to determine if the changes in impairment and disability measures for the upper and lower extremities were equivalent during the post-stroke rehabilitation period and whether the rates of change were maintained 6 months after discharge from rehabilitation. A prospective cohort study design was used. One-hundred-and-thirty-two people who had sustained a stroke and who were enrolled in an intensive functional rehabilitation programme were recruited. Upper and lower extremity impairments and disabilities were evaluated at admission, at discharge from rehabilitation and 6 months later. During active rehabilitation, the changes in both extremities were smaller for the impairment measures (standardized response mean (SRM), 0.37-0.63) than the disability measures (SRM, 0.76-1.05). While the changes in upper and lower extremities were equivalent for impairment measures, they were larger in the lower extremity for disability measures, indicating that the rate of functional improvement was faster in the lower extremity during active rehabilitation. After discharge, however, while the rate of motor recovery in the lower extremity dropped (SRM, 0.54-0.18), it was maintained in the upper extremity (SRM, 0.45 and 0.42). Present findings indicate that functional (disability) measures improve faster than impairment measures in both extremities during the active rehabilitation period and suggest that motor recovery occurs at a different rate in the upper and lower extremities, with that of the upper extremity occurring later and extending into the period after discharge from active rehabilitation.

Aged↗

PubMed2003

Assessing mobility and locomotor coordination after stroke with the rise-to-walk task.

INTRODUCTION: To assess mobility and locomotor coordination after stroke with the rise-to-walk task (RTW) and to examine the construct and concurrent validity of this task. METHODS: Nineteen subjects who had sustained a stroke and 19 healthy subjects performed the RTW task. The performance was recorded simultaneously with 2 clinical methods and 1 instrumented method. The RTW duration and fluidity of the motor strategy (fluid or nonfluid) were compared between groups and between methods. The relationship between RTW duration and 3 locomotor-related disability tests, as well as 1 motor impairment test, was studied. RESULTS: The subjects with stroke took 65% more time to complete the RTW task, and 16/19 separated the tasks of rising and walking (nonfluid strategy). Measures of the RTW duration with clinical methods were strongly correlated (r = 0.84 to 0.98) to those from the instrumented method, and the motor strategy was successfully assessed from video records. The duration was moderately correlated to scores from other locomotor-related tests, but not to the motor impairment test. DISCUSSION: The assessment of mobility and locomotor coordination with the RTW task indicate that both outcomes are impaired after stroke and that clinical methods provide a valid measurement of the task.

Adult↗

PubMed2003

Arm and leg impairments and disabilities after stroke rehabilitation: relation to handicap.

OBJECTIVES: (1) To examine the relationships between measures of impairment and disability for the arm and leg with a measure of handicap and (2) to identify the impairment or disability most strongly related to handicap situations. DESIGN: Prospective cohort study. SETTING: Intensive functional rehabilitation unit and community. PATIENTS: One hundred and two persons who had a stroke. MAIN OUTCOME MEASURES: Arm and leg impairments and disabilities were evaluated with reliable and valid tests at discharge from rehabilitation. Six months later, handicap situations were evaluated with the Assessments of Life Habits (LIFE-H). RESULTS: Arm and leg impairments and disabilities are correlated with handicap situations. Disability of the leg is more strongly associated with handicap than arm disability. Arm and leg disabilities are not statistically more strongly related to handicap than arm and leg impairments. CONCLUSIONS: The high correlations found between handicap situations and the impairment and disability measures of the leg provide new information that support the importance of mobility to promote integration after stroke.

Aged↗

PubMed2003

A fluidity scale for evaluating the motor strategy of the rise-to-walk task after stroke.

OBJECTIVE: (1) To develop an ordinal scale (content validity) for assessing fluidity of the rise-to-walk task (RTW); (2) to examine the concurrent validity of the fluidity scale; (3) to study the inter-rater reliability of the scale. DESIGN: A group of physical therapists participated in the scale development (content validity); a cross-sectional design was used to study the agreement between the fluidity scale and the fluidity index (criterion measure) obtained with the instrumented method (concurrent validity) and to examine the inter-rater reliability of the scale. SETTING: Rehabilitation centre. SUBJECTS: Nineteen persons with a chronic stroke and 19 age- and gender-matched healthy subjects. MAIN OUTCOME MEASURES: For the validation study: the fluidity index (FI) and the scores from the fluidity scale; for the inter-rater reliability study: duration of the RTW task and fluidity scores. RESULTS: The FI values did not overlap across categories of the scale and the relationship between FI values and the fluidity scores was 0.99. The weighted kappa (kappa(w)) indicated a substantial level of agreement between the new raters (kappa(w) = 0.78) and between the new raters and the expert rater (kappa(w) = 0.71). Corresponding mean intraclass correlation coefficients for the RTW duration were 0.95. CONCLUSION: These results indicate that the descriptors of the scale provided a gradation of fluidity comparable to the gold standard measure (FI) and that trained clinicians can use the fluidity scale with a substantial level of reliability. The RTW task is a simple clinical tool for assessing mobility and motor strategies (locomotor co-ordination) in patients presenting varying degrees of motor recovery after stroke.

Case-Control Studies↗

PubMed2003

Assessing advanced locomotor recovery after total hip arthroplasty with the timed stair test.

OBJECTIVE: To assess advanced locomotor performance with the timed stair test (TST) and to determine if the level of performance of a group of women one year after hip replacement changed with the functional demands of the tasks. DESIGN: Comparison of the performance of two groups of women. SETTING: General community. PARTICIPANTS: A convenient sample including 18 women who had had a total hip replacement 11 months earlier (patients) and 15 healthy age-matched women (comparison group). MAIN OUTCOME MEASURES: Three tests were administered: the 10-m walk test, the unloaded TST and the loaded TST (10 kg). The duration of each test was recorded and transformed into speed and the level of performance was assessed by calculating percentage deficit using corresponding values from the comparison group. The TST is made of four subtasks: (1) standing up and walking, (2) ascending stairs, (3) turning and descending stairs, (4) walking back, turning and sitting down. RESULTS: Significant differences in performance were found for all three tests with the patients showing a slower performance. The percentage deficits increased significantly from the less difficult (walking: 18%) to the more difficult conditions (unloaded TST: 23% and loaded TST: 28%), with the greatest deficits found during stair descent. Strong correlations were also found between walking deficits and TST deficits (loaded: r = 0.82; unloaded: r = 0.88). CONCLUSIONS: By combining mobility, walking and stair activities, the TST can be used to assess various components of advanced locomotor performance. The progressive level of difficulty of the TST subtasks as well as the addition of a load make it useful to detect subtle locomotor disabilities.

Aged↗

PubMed2002

Motor learning produces parallel dynamic functional changes during the execution and imagination of sequential foot movements.

The aim of the present positron emission tomography study was to measure the dynamic changes in cerebral activity before and after practice of an explicitly known sequence of foot movements when executed physically and to compare them to those elicited during motor imagery of the same movements. Nine healthy volunteers were scanned while performing both types of movement at an early phase of learning and after a 1-h training period of a sequence of dorsiflexions and plantarflexions with the left foot. These experimental conditions were compared directly, as well as to a perceptual control condition. Changes in regional cerebral blood flow associated with physical execution of the sequence early in the learning process were observed bilaterally in the dorsal premotor cortex and cerebellum, as well as in the left inferior parietal lobule. After training, however, most of these brain regions were no longer significantly activated, suggesting that they are critical for establishing the cognitive strategies and motor routines involved in executing sequential foot movements. By contrast, after practice, an increased level of activity was seen bilaterally in the medial orbitofrontal cortex and striatum, as well as in the left rostral portion of the anterior cingulate and a different region of the inferior parietal lobule, suggesting that these structures play an important role in the development of a long lasting representation of the sequence. Finally, as predicted, a similar pattern of dynamic changes was observed in both phases of learning during the motor imagery conditions. This last finding suggests that the cerebral plasticity occurring during the incremental acquisition of a motor sequence executed physically is reflected by the covert production of this skilled behavior using motor imagery.

Adult↗

PubMed2002

Intermittent intensive physiotherapy in children with cerebral palsy: a pilot study.

The aims of the study were: (1) to determine the feasibility of a rehabilitation program combining intensive therapy periods (4 times/week for 4 weeks) with periods without therapy (8 weeks) over a 6-month period in severely impaired children with cerebral palsy (CP); and (2) to measure changes in gross motor function after intensive therapy periods (immediate effects) and rest periods (retention). A convenient sample included five children (two females, three males; mean age 22.6 months [SD 9.9]) with severe forms of CP with impairment of four limbs and trunk (GMFCS levels IV and V). A multiple-baseline design was used. Changes in motor performance were assessed by a blind evaluator using the Gross Motor Function Measure. Visual and statistical analyses followed. Level of compliance during intensive therapy was 93.1%. Children received a mean of 30 treatments over the 24 weeks of the experimental phase compared with the 48 treatments they would have received routinely. Increases in GMFM scores (mean 9.2%; range 3 to 15%) were significant in three children (p<0.05) and all participants maintained their motor performance during the two 8-week rest periods. Results showed that four treatments per week over a 4-week period were well tolerated when separated by rest periods. The intermittent program led to improvements in motor function that were maintained over the rest periods. Results underline the need to reconsider the organization of physical rehabilitation programs. A regime that is intensive enough without being tiring and one that provides practice conditions for consolidating motor skills learned during the intensive therapy period may best optimize motor training.

Cerebral Palsy↗

PubMed1997

Impaired viscoelastic behaviour of spastic plantarflexors during passive stretch at different velocities.

OBJECTIVE: The aim of this study was to evaluate the effect of velocity on non-reflexly induced resistive torque (RT) responses of the spastic plantarflexors (PFs) of subjects with spinal cord injuries. DESIGN: Descriptive study, transversal. BACKGROUND: In spastic muscles, non-reflex changes such as increased muscle stiffness, contractures and atrophy have been reported. These changes probably alter muscle tensile properties and viscoelastic behaviour. METHODS: Six subjects with chronic (1-3 yr) spinal cord injuries (SCI) and 12 normal controls (CTLs) participated in this study. Passive ankle dorsiflexions (DFs), ranging from -35 degrees to 5 degrees of DF, were randomly imposed at 5 degrees /s, 10 degrees /s, 20 degrees /s, 40 degrees /s, 60 degrees /s, 120 degrees /s and 180 degrees /s using an isokinetic dynamometer (Kin-Com(TM)). Unwanted muscle activity was detected using surface electrodes on the soleus and tibialis anterior muscles. RESULTS: The results show first that RT rose with increasing velocity; the RT increment reached statistical (analysis of variance (ANOVA); Scheffé post-hoc procedure) significance (P < 0.01) at a lower velocity for the CTLs (40 degrees /s) group than for the SCI group (60 degrees /s). Second, significantly (t-test; P < 0.001) larger net increments of RT (RT at each velocity minus RT at 5 degrees /s) were found for the CTLs at 180 degrees /s than for the SCI group whose RT plateaued at 60 degrees /s. Finally, whereas the RT-velocity relationship was linear (r = 0.94) in the CTLs, that of the SCI group followed a power regression model (r = 0.85). CONCLUSIONS: These results show that the spastic PFs of the subjects with SCIs have an impaired velocity-sensitive behaviour, especially at high velocities of stretch where greater resistance is expected.

Journal Article↗