Effects of a 6-week virtual reality treadmill training on frailty in people with multiple sclerosis

Abstract

Background and Purpose Up to two thirds of people with multiple sclerosis (pwMS) are frail. Frailty within MS is associated with adverse clinical outcomes such as falls, independently of age, gender, and disability levels. Consequently, there is a critical need to identify strategies to counteract frailty in pwMS. Since MS affects both motor and cognitive function, cognitive-motor rehabilitation is a potentially viable strategy to reduce frailty in pwMS. Therefore, the purpose of this study was to examine the effects of a cognitive-motor rehabilitation intervention consisting of virtual reality treadmill training (VRTT) compared to treadmill training (TT) alone, on frailty in pwMS. Methods Fifty-three people with relapsing-remitting MS [age=50.8 years (SD=9.2); 77.4% female; expanded disability status scale (EDSS) range=2.0-6.0] were randomized to VRTT (n=25) or to TT alone (n=28). Both groups trained three times per week for six weeks. Frailty was evaluated through the deficit accumulation model before and after the intervention using standard validated procedures. A 40-item frailty index was taken as the main study outcome. Results Forty-five participants, 23 in the experimental group and 22 in the control group, completed the intervention and the pre- and post-training frailty assessments. Per-protocol repeated measures ANOVAs revealed that frailty index scores improved in both groups (time effect: p˂0.001, η2=0.262). The frailty index decreased from 0.29±0.13 to 0.27±0.12 in the TT alone group, and from 0.31±0.15 to 0.26±0.15 in the VRTT group. However, group by time interactions were not significant (p=0.119, η2=0.055). Discussion The current study provided evidence that treadmill training with or without virtual reality may be a viable strategy to reduce frailty in pwMS. Interestingly, VRTT tended to have a greater effect in terms of frailty reduction (Δ∼0.05) compared to TT alone (Δ∼0.02) as indicated by a clinically meaningful change, defined as a reduction greater than 0.03 in frailty index score. Up to two thirds of people with multiple sclerosis (pwMS) are frail. Frailty within MS is associated with adverse clinical outcomes such as falls, independently of age, gender, and disability levels. Consequently, there is a critical need to identify strategies to counteract frailty in pwMS. Since MS affects both motor and cognitive function, cognitive-motor rehabilitation is a potentially viable strategy to reduce frailty in pwMS. Therefore, the purpose of this study was to examine the effects of a cognitive-motor rehabilitation intervention consisting of virtual reality treadmill training (VRTT) compared to treadmill training (TT) alone, on frailty in pwMS. Fifty-three people with relapsing-remitting MS [age=50.8 years (SD=9.2); 77.4% female; expanded disability status scale (EDSS) range=2.0-6.0] were randomized to VRTT (n=25) or to TT alone (n=28). Both groups trained three times per week for six weeks. Frailty was evaluated through the deficit accumulation model before and after the intervention using standard validated procedures. A 40-item frailty index was taken as the main study outcome. Forty-five participants, 23 in the experimental group and 22 in the control group, completed the intervention and the pre- and post-training frailty assessments. Per-protocol repeated measures ANOVAs revealed that frailty index scores improved in both groups (time effect: p˂0.001, η2=0.262). The frailty index decreased from 0.29±0.13 to 0.27±0.12 in the TT alone group, and from 0.31±0.15 to 0.26±0.15 in the VRTT group. However, group by time interactions were not significant (p=0.119, η2=0.055). The current study provided evidence that treadmill training with or without virtual reality may be a viable strategy to reduce frailty in pwMS. Interestingly, VRTT tended to have a greater effect in terms of frailty reduction (Δ∼0.05) compared to TT alone (Δ∼0.02) as indicated by a clinically meaningful change, defined as a reduction greater than 0.03 in frailty index score.