Virtual reality and the prevention of falls in the real world.

www.thelancet.com Published online August 11, 2016 http://dx.doi.org/10.1016/S0140-6736(16)31347-2 1 Falls are a leading cause of morbidity and mortality in older adults. Studies conducted in Europe, the USA, and Australia show that roughly a third of communityliving people aged 65 years or older fall at least once per year, with half of this number having multiple falls in this period. Falls impose major social and economic burdens for individuals, their families, health services, and the economy. With the number of older people increasing across the world, the costs associated with falls will increase substantially in the coming decades, making the prevention of falls an urgent public health challenge. The Article by Anat Mirelman and colleagues reported in The Lancet presents positive fi ndings of an innovative fall prevention strategy. Their study was a multicentre, randomised controlled trial that compared a combined treadmill training and virtual reality (VR) intervention with treadmill training alone in 302 participants aged 60–90 years at high risk of falls. The VR component consisted of motion capture of the participants’ feet, which was then projected onto a screen, with challenges in the form of obstacles, pathways, and distractors that required continual adjustment of steps. The groups were well matched at baseline, and the incident rate of falls was similar in both groups before training, with 10·7 (SD 35·6) falls per 6 months in the treadmill training group and 11·9 (39·5) falls per 6 months for the treadmill training plus VR group. The main fi nding, assessed in a modifi ed intention-to-treat sample of 282 (93%) participants, was that falls were reduced by 42% in the treadmill training plus VR group compared with the treadmill training group in the 6 month period following the end of training (incident rate ratio 0·58, 95% CI 0·36−0·96; p=0·033). Furthermore, important secondary outcome measures, including gait variability during obstacle negotiation, functional balance and gait, and quality of life were signifi cantly improved in the treadmill training plus VR group after training compared with the treadmill training group, with some gains retained at the 6 month follow-up. The fi nding of a 42% reduction in falls is in line with the most eff ective fall preventions that have assessed more traditional group-based and homed-based exercise interventions in older people and well above the average reduction of 17% for exercise interventions reported in systematic reviews. It is also notable that the reduction in falls reported in the current trial is made in comparison to a treadmill walking intervention of similar intensity, as opposed to no intervention or usual care. Unlike traditional exercise where the principle of “use it or lose it” is assumed, the intervention was of short duration (ie, 6 weeks). The 6 month retention of improved functional balance and gait and improved obstacle negotiation suggests that task-specifi c learning relevant for negotiating hazards and avoiding trips in the real world might have contributed to the reduction of falls seen in the treadmill training plus VR group. This mechanism is consistent with complementary research that has shown short-term trip and slip training can have lasting benefi ts for fall prevention in older people. A major diff erence in the two interventions compared in this trial was the cognitive component included in the treadmill training plus VR group, yet no diff erential improvement in executive function was detected in participants assigned to this group (p=0·40 for executive function index, p=0·61 for attention index score). It could be that pen-and-paper cognitive tests are not sensitive enough to detect diff erences, but might also suggest that the intervention eff ects were quite specifi c and restricted to improved gait adaptability in situations requiring focused attention and planning. Participants with Parkinson’s disease (who represented more than 40% of the study population) benefi ted the most from the combined intervention (incident rate ratio 0·45, 95% CI 0·24−0·86; p=0·015). This fi nding is encouraging because, despite evidence for remediation of physical fall risk factors, there is little evidence of translation of these improvements into the prevention of falls in this group. Notably, secondary analyses of a recent trial examining the eff ects of the cholinesterase inhibitor rivastigmine on falls in people with Parkinson’s disease suggest the benefi cial eff ect may also have been related more to reducing gait variability than to improving cognition. Mirelman and colleagues’ fi ndings have important implications for clinical practice. No serious adverse events occurred and adherence was good. A health economic analysis was not presented, and although it is the case that VR training is not substantially more resource-intensive than treadmill training, one-on-one supervision was used in this study. It is conceivable, Virtual reality and the prevention of falls in the real world