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.

Rehabilitation interventions involving virtual reality (VR) technology have been developed for the promotion of functional independence post stroke. A scoping review was performed to examine the efficacy of VR-based interventions on balance and mobility disorders post stroke. Twenty-four articles in the English language examining VR game-based interventions and outcomes directed at balance and mobility disorders were included. Various VR systems (customized and commercially available) were used as rehabilitation tools. Outcome measures included laboratory and clinical measures of balance and gait. Outcome measures of dynamic balance showed significant improvements following VR-based interventions as compared to other interventions. Further, it was observed that VR-based intervention may have favorable effects in improving walking speed and the ability to deal with environmental challenges, which may also facilitate independent community ambulation. VR-based therapy thus has the potential to be a useful tool for balance and gait training for stroke rehabilitation. Utilization of motor learning principles related to task-related training may have been an important factor leading to positive results. Other principles such as repetition, feedback etc. were used in studies but were not explored explicitly and may need to be investigated to further improve the strength of results. Lastly, robust study designs with appropriate attention towards the intensity and dose-response aspects of VR training, clear study objectives and suitable outcomes would further aid in determining evidence-based efficacy for VR game-based interventions in the future.

The maintenance of upright equilibrium is essentially a sensorimotor integration task. The central nervous system (CNS) has to generate appropriate and complex motor responses based on the selective and rapid integration of sensory information from multiple sources. Since each sensory system has its own coordinate framework, specific time delay and reliability, sensory conflicts may arise and represent situations in which the CNS has to recalibrate the weight attributed to each particular sensory input. The resolution of sensory conflicts may represent a particular challenge for older adults given the age-related decline in the integrity of many postural regulating systems, including musculoskeletal and sensory systems, as well as neural processing and conduction of information. The effects of aging and adaptation (by repeated exposures) on the capability of the CNS to select pertinent sensory information and resolve sensory conflicts were thus investigated with virtual reality (VR) in the present study.

Walking speed, which is often reduced after stroke, can be influenced by the perception of optic flow (OF) speed. The present study aims to: 1) compare the modulation of walking speed in response to OF speed changes between persons with stroke and healthy controls and 2) investigate whether virtual environments (VE) manipulating OF speed can be used to promote volitional changes in walking speed post stroke.

BACKGROUND: Limited evidence supports the effects of short-interval high-intensity interval training (HIIT) for improving cardiorespiratory fitness (V̇O ₂ peak) after stroke. We aimed to compare the effects of 12 weeks of short-interval HIIT versus moderate-intensity continuous training (MICT) on V̇O ₂ peak, cardiovascular risk factors, and mobility outcomes among individuals ≥6 months poststroke. METHODS: This study was a multi-site, 12-week randomized controlled trial (NCT03614585) with an 8-week follow-up. Participants were randomized into 3 d/wk of HIIT (10×1 minute 80%–100% heart rate reserve interspersed with 1 minute 30% heart rate reserve [19 minutes]) or MICT (20–30 minutes 40%–60% heart rate reserve). Secondary outcomes of the trial, including V̇O ₂ peak, cardiovascular risk factors (carotid-femoral pulse wave velocity, blood pressure, and waist-hip ratio), and mobility (6-minute walk test, 10 m gait speed), were reported. Linear mixed model analyses with a group×study time point interaction evaluated between-group differences. RESULTS: Of the 305 potential participants, 82 consented (mean [SD] age 64.9 [9.3] years, 32 females [39%], 1.8 [1.2] years poststroke) and were randomized to HIIT (n=42, mean [SD] baseline V̇O ₂ peak 17.3 [5.9] mL/kg·min) or MICT (n=40, mean [SD] baseline V̇O ₂ peak 17.2 [6.0] mL/kg·min). Participants attended 82% of visits (n=2417/2952). No adverse events occurred during the study period. A significant group×study time point interaction was found (χ ² =8.46; P =0.015) for V̇O ₂ peak at 12 weeks (mean difference, 1.81 [95% CI, 0.58–3.04]; P =0.004) whereby the HIIT group had greater gains in V̇O ₂ peak (∆3.52 mL/kg·min [95% CI, 2.47–4.57]; P <0.001) compared with the MICT group (∆1.71 mL/kg·min [95% CI, 0.55–2.86]; P =0.001). There was no between-group difference in V̇O ₂ peak (mean difference, 1.08 [95% CI, −0.26 to 2.42]; P =0.11) at 8-week follow-up. No group×study time point interactions were found for cardiovascular risk factors or mobility outcomes. CONCLUSIONS: Short-interval HIIT may be an effective alternative to MICT for improving V̇O ₂ peak at 12 weeks postintervention. REGISTRATION: URL: https://clinicaltrials.gov ; Unique identifier: NCT03614585.