Virtual reality-based training has found increasing use in neurorehabilitation to improve upper limb training and facilitate motor recovery.
The aim of this study was to directly compare virtual reality-based training with conventional therapy.
In a multi-center, parallel-group randomized controlled trial, patients at least 6 months after stroke onset were allocated either to an experimental group (virtual reality-based training) or a control group receiving conventional therapy (16×45 minutes within 4 weeks). The virtual reality-based training system replicated patients´ upper limb movements in real-time to manipulate virtual objects.
Blinded assessors tested patients twice before, once during, and twice after the intervention up to 2-month follow-up for dexterity (primary outcome: Box and Block Test), bimanual upper limb function (Chedoke-McMaster Arm and Hand Activity Inventory), and subjective perceived changes (Stroke Impact Scale).
54 eligible patients (70 screened) participated (15 females, mean age 61.3 years, range 20–81 years, time since stroke 3.0±SD 3 years). 22 patients were allocated to the experimental group and 32 to the control group (3 drop-outs). Patients in the experimental and control group improved: Box and Block Test mean 21.5±SD 16 baseline to mean 24.1±SD 17 follow-up; Chedoke-McMaster Arm and Hand Activity Inventory mean 66.0±SD 21 baseline to mean 70.2±SD 19 follow-up. An intention-to-treat analysis found no between-group differences.
Patients in the experimental and control group showed similar effects, with most improvements occurring in the first two weeks and persisting until the end of the two-month follow-up period. The study population had moderate to severely impaired motor function at entry (Box and Block Test mean 21.5±SD 16). Patients, who were less impaired (Box and Block Test range 18 to 72) showed higher improvements in favor of the experimental group. This result could suggest that virtual reality-based training might be more applicable for such patients than for more severely impaired patients.
Virtual reality-based rehabilitation systems are gaining popularity because of their ease of use, applicability to wide range of patients, and ability to provide patient-personalized training [1–3]. Additional reported benefits of virtual reality systems for both patients and health providers include increased therapy efficiency and a high level of attention in patients during training .
One of the main struggles therapists encounter is keeping patients motivated throughout conventional training sessions. The Yerkes-Dodson Law describes the relationship between arousal or motivation and performance . At first, an increase in arousal and motivation leads to an increase in performance. But once a certain point is reached, this point can vary based on many factors including the task, the participant, and the context, the relationship becomes inverse and increases in arousal caused decreases in performance. In line with these ideas, previous research has shown that increased performance leads to greater improvement in patients after stroke up to a certain point. Virtual reality-based systems allow manipulation of arousal through training settings to ensure that peak performance is maintained for as large a portion of the therapy time as possible .
Laver et al. systematically evaluated the literature regarding the efficacy of virtual reality-based training in stroke rehabilitation in 2011 and in its updates in 2015 and 2017 [3, 7, 8]. Their current meta-analysis of 22 trials including 1038 patients after stroke that focused on upper limb function did not reveal a statistically significant difference between VR-based training and conventional therapy (0.07 standard deviation higher in virtual reality-based compared to conventional therapy. Furthermore, the authors rated the quality of evidence as low, based on the GRADE system. However, for ADL function the experimental groups showed a 0.25 higher standard deviation than the conventional therapy groups based on ten studies, including 466 patients after a stroke with moderate quality of evidence.
Only 10% of the included studies included more than 50 participants, with mean ages between 46 to 76 years. However, due to the different systems used no conclusion could be drawn regarding grip strength, dosage, type or program of the virtual reality-based training. Furthermore, the authors pointed out the low sample sizes and the low methodological quality of the reported trials. In their recommendations for further research, the authors encouraged researchers and clinicians again to conduct larger trials and to increase the detail in reporting to enable more firm conclusions.
YouGrabber (now renamed Bi-Manu Trainer), a game-based virtual reality system designed for upper-limb rehabilitation, has been shown to be effective in children with cerebral palsy. A 2-subject feasibility study indicated that the findings might extend to chronic stroke patients [9, 10]. Both male subjects, who were trained three years after insult onset, showed increases in scores for the bimanual activities of daily living focused Chedoke McMaster Arm and Hand Activity Inventory (CAHAI) that persisted at the final follow-up, and corresponding cortical changes measured with fMRI.
Based on these findings the present multicenter parallel group randomized single-blinded trial aimed to investigate the efficacy of a virtual reality-based training with the YouGrabber training device (now renamed Bi-Manu Trainer) compared to conventional therapy. The study was designed to test the hypothesis that patients in the chronic stage after stroke in the virtual reality-based training group will show no higher post-intervention performance in the Box and Block Test (BBT) compared to patients receiving an equal training time of physiotherapy or occupational therapy.
For comparison with published and ongoing international studies we selected the Box and Block Test as the primary outcome measure and the CAHAI as the secondary outcome measure.
Methods and materials
This prospective, multicenter, single-blinded, parallel-group randomized trial was conducted in the outpatient departments of three rehabilitation hospitals in the German and French speaking parts of Switzerland: University hospital Inselspital Bern, Buergerspital Solothurn, and Reha Rheinfelden. In the study plan, each hospital was responsible for the recruitment, assessment, and therapy of 20 patients: 10 patients for the experimental group (EG) and 10 for the control group (CG), respectively.
More details regarding the study methodology can be found in the study flow chart in Fig 1 and the previously published study protocol strictly followed by each center (http://trialsjournal.biomedcentral.com/articles/10.1186/1745-6215-15-350) . Ethics approval was warranted by the ethics committee of the Canton Aargau (2012/065) and the Canton Berne (220/12). The study was registered with ClinicalTrials.gov: NCT01774669 before the start of patient recruitment.