Claire Perez

Cognitive Load and Dual-Task Performance During Locomotion Poststroke: A Feasibility Study Using a Functional Virtual Environment

Background Gait and cognitive functions can deteriorate during dual tasking, especially in people with neurological deficits. Most studies examining the simultaneous effects of dual tasking on motor and cognitive aspects were not performed in ecological environments. Using virtual reality technology, functional environments can be simulated to study dual tasking. Objectives The aims of this study were to test the feasibility of using a virtual functional environment for the examination of dual tasking and to determine the effects of dual tasking on gait parameters in people with stroke and age-matched controls who were healthy. Design This was a cross-sectional observational study. Methods Twelve community-dwelling older adults with stroke and 10 age-matched older adults who were healthy participated in the study. Participants walked on a self-paced treadmill while viewing a virtual grocery aisle projected onto a screen placed in front of them. They were asked to walk through the aisle (single task) or to walk and select (“shop for”) items according to instructions delivered before or during walking (dual tasking). Results Overall, the stroke group walked slower than the control group in both conditions, whereas both groups walked faster overground than on the treadmill. The stroke group also showed larger variability in gait speed and shorter stride length than the control group. There was a general tendency to increase gait speed and stride length during dual-task conditions; however, a significant effect of dual tasking was found only in one dual-task condition for gait speed and stride duration variability. All participants were able to complete the task with minimal mistakes. Limitations The small size and heterogeneity of the sample were limitations of the study. Conclusions It is feasible to use a functional virtual environment for investigation of dual tasking. Different gait strategies, including an increase or decrease in gait speed, can be used to cope with the increase in cognitive demands required for dual tasking.

Sensorimotor enhancement with a mixed reality system for balance and mobility rehabilitation

We have developed a mixed reality system incorporating virtual reality (VR), surface perturbations and light touch for gait rehabilitation. Haptic touch has emerged as a novel and efficient technique to improve postural control and dynamic stability. Our system combines visual display with the manipulation of physical environments and addition of haptic feedback to enhance balance and mobility post stroke. A research study involving 9 participants with stroke and 9 age-matched healthy individuals show that the haptic cue provided while walking is an effective means of improving gait stability in people post stroke, especially during challenging environmental conditions such as downslope walking.

An Instrumented Cane Devised for Gait Rehabilitation and Research

Background and Purpose. We have developed a novel cane device to be used in conjunction with a treadmill‐based virtual reality (VR) locomotor system. This proof‐of‐principle paper reports the rationale, instrumentation, feasibility, and clinical implications of the cane device, as well as preliminary results from persons with stroke and healthy older adults using the device. Subjects. Five persons with stroke and 5 healthy older adults participated. Methods. Average walking speeds with and without use of the cane are compared between the overground physical environment (PE) and a self‐paced, treadmill‐based virtual environment (VE). Additional gait parameters examined while walking with and without the cane in the VE are: (1) gait variability quantified as the coefficient of variation (% CV) for stride duration, and (2) step width. We also reported and discussed the vertical loading forces transmitted through the cane during self‐paced treadmill walking in the VE. Results. Results reveal that walking with the instrumented cane on a treadmill is feasible for use in both healthy and stroke populations. It is evident that people who normally rely on a walking cane benefit more from the instrumented cane than people who normally walk unaided. Discussion and Conclusion. This work represents the first instrumented cane for use with a treadmill‐based locomotor system. The use of this assistive device would add to the ecological validity of such gait rehabilitation systems. It is expected that gait training with the instrumented cane can be carried over to overground walking, although further studies are warranted.

Development of a force-sensing cane instrumented within a treadmill-based virtual reality locomotor system

We have developed a novel cane device to be used in conjunction with a treadmill-based virtual reality (VR) locomotor system. The instrumentation of such a cane device is described and results examining its use and feasibility as a proof of principle are provided in this preliminary study involving five persons with stroke and 5 healthy participants. Average walking speeds with and without the cane are compared between the overground physical environment (PE) and the treadmill-based virtual environment (VE). Gait variability quantified as the % coefficient of variation (CV) for stride duration with and without the cane in the VE is also examined. Furthermore, the vertical loading forces exerted on the cane during level walking in the VE are reported and discussed. Results reveal that walking with the treadmill cane is feasible for use in both healthy and stroke populations. It is evident that people who normally rely on a walking cane benefit more from the instrumented cane than those people who normally walk unaided. This work represents the first instrumented cane for use with a treadmill-based locomotor system.

A VR-haptic locomotor system to retrain anticipatory postural adjustments post stroke

The ability to use haptic input through light contact to improve stability while walking post-stroke is investigated in a virtual environment (VE). Persons with stroke and healthy participants walk in a VE where they encounter changes in the slope of the support surface. Kinematic, kinetic, and electromyographic data analyses will be used to show the anticipatory postural adjustments made leading up to and after a transition to a sloped surface. Pilot testing shows that the transition to sloped surface is more challenging for the stroke participant tested, as compared to an age-matched control. Modifications to the current protocol will improve the feasibility of not only task completion by both healthy and neurologically impaired participants, but also the ability to use and evaluate the use of haptic information for stability while walking in a VE with slope changes.

A virtual reality-based paradigm to study functional dual task performance during locomotion post stroke

The purpose of this study is to examine dual task performance during locomotion in a functional virtual setting. A virtual reality-based paradigm was developed in order to achieve this goal. To date, four participants who had a stroke completed the study protocol. Gait parameters and cognitive performance indicators varied between subjects. Further data collection and analysis is currently being performed.

A novel approach to integrate VR exer-games for stroke rehabilitation: Evaluating the implementation of a ‘games room’

This study evaluates the integration of virtual reality (VR) exer-games for people post-stroke through the implementation of a “exer-games room” in an inpatient rehabilitation hospital. Qualitative data (interviews with patients and clinicians) and quantitative data (from the first year of operation of the games room) are synthesized and reviewed to provide an overall interpretative evaluation. The Consolidated Framework for Implementation Research (CFIR) is used to analyze the successful and less successful factors involved in the implementation.

Amount and Content of Sensorimotor Therapy Delivered in Three Stroke Rehabilitation Units in Quebec, Canada

Purpose: This study creates a baseline clinical portrait of sensorimotor rehabilitation in three stroke rehabilitation units (SRUs) as a first step in implementing a multi-centre clinical research platform. Method: Participants in this cross-sectional, descriptive study were the patients and rehabilitation teams in these SRUs. Prospective (recording of therapy time and content and a Web-based questionnaire) and retrospective (chart audit) methods were combined to characterize the practice of the rehabilitation professionals. Results: The 24- to 39-bed SRUs admitted 100-240 inpatients in the year audited. The mean combined duration of individual occupational and physical therapy was 6.3-7.5 hours/week/patient. When evening hours and the contributions of other professionals as well as group therapy and self-practice were included, the total amount of therapy was 13.0 (SD 3) hours/patient/week. Chart audit and questionnaire data revealed the Berg Balance Scale was the most often used outcome measure (98%-100%), and other outcome measure use varied. Clinicians favoured task-oriented therapy (35%-100%), and constraint-induced movement therapy (0%-15%), electrical stimulation of the tibialis anterior (0%-15%), and body weight-supported treadmill training (0%-1%) were less often used. Conclusions: This study is the first to provide objective data on therapy time and content of stroke rehabilitation in Quebec SRUs.

The effects of increased attentional demand on the perception of visual vertical

Balance and locomotion involve multi-sensory integration while meeting environmental demands. In addition, increased task complexity negatively affects postural control in aging and patient populations. The goal of this pilot study was to examine the effects of aging and cognitive load on the visual perception of vertical. Four young and 3 older individuals participated. Subjective visual vertical (SVV) performance deteriorated more in the older individuals as the task complexity increased. However, within group variability was high. The expected increase in sample size should further clarify the role of each sensory system in the perception of SVV.