Systemic Literature Review of the Use of Virtual Reality for Rehabilitation in Parkinson Disease
Background: Functional rehabilitation is important when managing Parkinson disease (PD). Virtual reality (VR) therapy is a noninvasive, potential alternative or adjunct to conventional therapies used during rehabilitation.
Observations: The authors searched for articles in Google Scholar, PubMed, Physiotherapy Evidence Database Score (PEDro), and Cochrane after setting specific requirements starting in July 2019. Methodologic quality was assessed by PEDro for randomized controlled trials. Among 89 studies identified, 28 included in this review evaluated VR therapy for use during rehabilitation for PD: 7 used immersive VR and 21 used nonimmersive VR. Among the immersive VR studies, 6 showed improvement in primary outcomes after adding VR therapy. Among the nonimmersive VR studies, 5 showed improvement with VR therapy when compared with conventional therapy, 9 showed improvement with VR and conventional therapy with no between group difference, and the remaining 7 showed improvement in primary outcomes after adding VR intervention. The quality and diversity of studies was a major limitation.
Conclusion: VR therapy is a promising rehabilitation modality for PD but more studies are needed. Additional investigations of VR therapy and PD should include direct comparisons between immersive and nonimmersive VR therapies.
Methods
Starting in July 2019, the authors searched several databases (PubMed, Google Scholar, Cochrane, and the Physiotherapy Evidence Database [PEDro]) for articles by using the keyword “Parkinson’s disease” combined with either “virtual reality” or “video games.” To find studies specific to rehabilitation, searches included the additional keyword: “rehabilitation.” After compiling an initial set of 89 articles, titles were reviewed to eliminate duplicates. The authors then read the abstracts to exclude study protocols, systematic reviews, and studies that used VR but did not focus on PD or any therapeutic outcome.
Articles were sorted into immersive or nonimmersive virtual reality categories. To be included as immersive VR, studies had to use any type of VR headset or full-scale VR room. Anything less immersive or similar to a traditional video game was included in the nonimmersive VR category. Articles that met inclusion criteria were selected for the systematic review. Criteria for inclusion in this review were: (1) English language; (2) included a study population focused on PD; (3) used some form of VR therapy; and (4) assessed potential rehabilitation by quantitative outcome measures. Only articles published in peer-reviewed journals were included.
Data were extracted into 2 tables specifically modified for this review: immersive and nonimmersive VR. Extracted data included study author name and publication date, study design, methodologic quality, sample size and group allocation, symptom progression via the Hoehn and Yahr Scale (1 to 5), VR modality, presence of control groups, primary outcomes, and primary findings.
Two of the authors (AS, BC) assessed the quality of each study by using the 11-point PEDro scale for randomized controlled trials (RCTs) (Table 1). Most criterion relate to the design and conduct of the study, but 3 focus on eligibility criteria (item 1), between-group statistical comparisons (item 10), and measures of variability (item 11). The total possible score was 10 because only 2 out of the 3 items on reporting quality contributed points to the total score (eligibility criteria specified did not).9
Results
This review is reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA).10 After screening and assessment, 28 articles met inclusion criteria for this review: 7 using immersive VR and 21 using nonimmersive VR (Figure). The immersive studies included 2 RCTs (both with PEDro scores of 5), 1 controlled study with a PEDro score of 5, 1 pre-post pilot study, and 3 cohort studies (Table 2). The nonimmersive studies included 13 RCTs with an average PEDro score of 5.8; 2 pre-post pilot studies, 1 repeated measures study with a historic control, 1 non-RCT, 2 pre-post prospective studies, and 2 cohort studies (1 retrospective and 1 prospective) (Table 3).
Several outcome and assessment tools were used; the most common measures were related to gait, balance, kinematics, and VR feasibility. Studies varied in VR modalities and protocol, ranging from 21 sessions of Nintendo Wii Fit gaming for 7 weeks to 1 session of VR headset use.
Immersive VR
There were fewer immersive VR studies and these studies had lower mean PEDro scores when compared with nonimmersive VR studies. The VR modalities in the immersive studies used a VR headset or a multisensory immersive system that included polarized glasses. All the studies showed positive improvement in primary outcomes with the exception of Ma and colleagues,which showed no difference in success rates or kinematics with moving balls, and only showed improvement in reaching for stationary balls.11 The mean number of participants in the studies was 18.4.
