The effectiveness of virtual reality interventions in improving balance in adults with impaired balance compared to standard or no treatment: A systematic review

Abstract

Review objective/questions Objective The aim of this systematic review is to search, critically appraise and synthesise the best available evidence on whether virtual reality interventions, including interactive gaming systems, are effective at improving balance in adults with impaired balance. Questions Specific review questions to be answered are as follows: Do virtual reality interventions: Improve balance outcome measure? Reduce the incidence of falls experienced? Reduce the number of falls experienced? Have any adverse effects? Background Description of the condition Within the World Health Organisation's International Classification of Functioning, Disability and Health (ICF), there is no definition of balance or balance impairment1. However, the ICF does provide one sentence of clarification regarding the function of the vestibular system in balance; “Sensory functions of the inner ear related to determining the balance of the body”1. Balance is achieved and maintained through the synergistic interaction of three main systems: visual, vestibular and muscular proprioception2. When one of these systems is affected there is a disruption to the individual's ability to maintain their static and/or dynamic balance. Considering the limited ICF definition1, it can be seen why balance disturbance is difficult to measure objectively, and clinicians rely on various validated outcome measures to determine effectiveness of treatment and interventions. The percentage of the population affected by balance impairment is indeterminable. The population is difficult to define due to the multiple pathologies, conditions and causes of balance disturbance. However, it is known that approximately eight million American adults experience chronic problems with their balance3. A disturbance in an individual's balance will also affect carer burden, function and activities of daily living. A survey in the USA reported that more than 33% of individuals with chronic balance problems experience difficulties with completing activities of daily living4 and have an increased risk of falling5. Over half of accidental deaths in the elderly are attributed to balance related falls6. Falls are a significant economic cost to health care providers, increasing number and length of hospital admissions, as well as the long-term treatment and prevention costs of patients with balance impairment. Description of the intervention Virtual reality (VR) has been defined by Weiss et al7 as the “use of interactive simulations created with computer hardware and software to present users with opportunities to engage in environments that appear and feel similar to real world objects and events”. There are many different terms used to describe the bespoke and commercially available systems currently employed within the health care sector to address and treat a variety of clinical problems and conditions. Interactive gaming systems (IGS) is a term more frequently used when describing the non-immersive, commercially available VR systems, i.e. Nintendo Wii, PlayStation i-toy, etc. The definition by Weiss7 is consistent with other terms used, and has key themes which can be used to determine if a system is VR and IGS. Computer hardware or software must be used to produce a scenario or environment which the individual can then interact with. It is currently unclear as to how extensively these systems are being used in the health care sector. How the intervention might work VR and IGS can be used in a variety of ways. Currently, most research is focused on the implications of using this technology on the upper limb, i.e. in stroke patient rehabilitation8. However, the systems are being used clinically to address balance issues in a variety of conditions (stroke, elderly fallers, Parkinson's disease, etc.). The theory underpinning how these systems work is that they retrain postural control9 whilst challenging other aspects of balance mechanisms, i.e. the vestibular system10, muscle strength and exercise tolerance11. VR has the potential to provide high repetition of treatment, conducted in a variety of settings (i.e. at home, community, in-patient and hospital settings), through independent or carer-supervised therapy8. The Nintendo Wii-Fit is an example of a commercially available system currently being used within various health care services as a treatment option12. The system potentially improves the control of postural muscles and co-ordination by getting the gamer to control the on-screen figures using subtle shifts in weight distribution on the Wii-Fit balance-board controller13. Why it is important to do this review It is important to conduct this review as the evidence for the use of VR and IGS to treat balance impairment has not been systematically evaluated before. IGS are being used in health care with limited evidence to support its inclusion in rehabilitation. Due to the relatively recent development of VR as an intervention, investigations into its effectiveness are sparse. A review of this nature will inform clinical practice, ensuring the most effective treatment is provided for patients with impaired balance. Inclusion criteria Types of participants Adult (16 years or older) hospitalised or community-based patients who are independently mobile and have been described as having impaired, altered or poor balance will be included in this review. ‘Impaired balance’ is a generalised term used to describe the balance of individuals that has been identified as reduced using a balance outcome measure (i.e. Berg or Brunel Balance Scores). Individuals with impaired balance may also be identified through experiencing or being at increased risk of falls. An increased risk and number of falls will be identified as participants who have fallen once or more in the past three months. A fall will be defined as “an unexpected event in which the participants come to rest on the ground, floor or lower level”14. “Near-misses” or examples of “near” falls will also be included. Participants who are experiencing or at risk of falling will only be included in the review if the cause of their falls has been identified as, or linked to, reduced, impaired or poor balance. Individuals who experience or are at increased risk of falls through other causes (i.e. cataracts, syncope, environmental reasons) will not be included within the review. Participants will not be excluded based on pathology or diagnosis, and studies will be included where participants have mixed aetiologies. Subgroup analysis of diagnosis/pathology and frequency of falls will be conducted, depending upon data availability in included studies. The frequency of falls subgroup will be divided according to the number of falls experienced on a weekly basis. High frequency of falls will be defined as participants experiencing greater than or equal to one fall per week. Low frequency of falls will be defined as those participants who experience falls at least once per month, but not as often as once per week, or who have experienced a fall within the past 3 months. Types of interventions Description of VR interventions which will be included: Virtual reality (immersive and non-immersive) Interactive gaming systems (immersive and non-immersive) Bespoke and commercially available systems. There are two key components which must be present in the description of the study intervention for inclusion into the systematic review: Use of computer hardware or software The interaction and/or engagement of the participant with the computer hardware or software. Only studies which use the intervention for rehabilitation purposes or goals will be included in the review. Any type of gaming software will be included. Trials will not be excluded based upon the “real world” reproduction within the intervention. Trials will be included which compare the intervention against standard care, standard care plus the intervention, and/or no treatment. Trials where there is no comparator will be sub-divided into the comparator control group. Types of outcomes The primary outcome measures of interest are: An objective measure of standing balance Incidence of falls experienced (yes or no) Number of falls experienced. Balance outcome measures included will be limited to those assessing standing balance only. Despite the potential for sitting balance to be treated, and therefore assessed, using VR interventions, this review will focus on standing balance measures only considering the clinical relevance and implications on practice for the treatment of older falls patients. Balance is clinically measured using a variety of outcome measures. Balance measures validated for use within an adult patient population and accepted for inclusion in this review are: Berg Balance Scale15 Brunel Balance Assessment16 Functional Reach17 Timed Up and Go Test18 Secondary outcome measures of interest include any adverse effects experienced, quality of life (through use of an objective measure i.e. EuroQOL), and number of days in hospital due to falls. Types of studies All randomised controlled trials (RCT) comparing the effectiveness of VR or IGS interventions for the treatment of adults with impaired balance will be included in this review. In the absence of RCT's, comparative studies without randomisation, cohort and case controlled studies will be included. Any study which has compared one type of virtual reality system to an alternative treatment or no treatment will be included. Studies which compare two types of virtual reality systems will not be included. Trials will be included where an objective measure of balance or number and/or incidence of falls are used (see Outcome Measure section). Exclusion Criteria This review will exclude studies where subscales of outcome measures have been used and which involve patients: Under the age of 16 years Who experience falls not caused by impaired, altered or poor balance Who are not mobile. Search Strategy The search strategy aims to find both published and unpublished studies written in the English language only (or that have been translated into English). A three-step search strategy will be utilised in this review. An initial limited search of MEDLINE and CINAHL will be undertaken, followed by analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified key words and index terms will then be undertaken across all included databases: The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, latest issue), MEDLINE (1950 to present), EMBASE (1980 to present), AMED (1985 to present), CINAHL (1982 to present), PsycINFO (1840 to present), PsycBITE (Psychological Database for Brain Impairment Treatment Efficacy, http://www.psycbite.com), OTseeker (http://www.otseeker.com/). Thirdly, the reference list of all identified reports and articles will be searched for additional studies. The search for unpublished studies will also use the following resources: Electronic searches of trials registers will be conducted, including Current Controlled Trials (http://www.controlled-trials.com) and the National Institute of Health Clinical Trials Database (http://www.clinicaltrials.gov) Contact the manufacturers of VR and IGS equipment to ask for details of any commercially funded trials. Studies reported in the period from October 1980 to October 2011 will be considered for inclusion in this review. Initial keywords to be used will be virtual reality, interactive, gaming, computer systems, balance, and falls. Assessment of methodological quality Two review authors (VB and FBH) will independently review the titles identified from the database searches. These review authors will then assess the trials based on the inclusion criteria, identified in the protocol method, and will sort the studies into groups: included, excluded, and unsure. The authors will document reasons for exclusion. Further information about the ‘unsure’ studies will be sought, with the ultimate decision regarding their inclusion determined by a third reviewer (LC). The methodological quality of each included study will be independently assessed by the two reviewers (VB and FBH). A standardised critical appraisal instrument from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) will be used to systematically comment on influence of bias on the results of the included studies (see Appendix I), and will cover the domains: Design Selection bias Confounders Blinding Data collection methods Withdrawn data/participants Each domain will be allocated with either a ‘yes’, ‘no’ or ‘unclear’ depending upon whether criteria are met. The summary of this tool will be used to generate a description of the risk of bias for each included study. A funnel plot may be produced to present reporting bias of included studies. Data extraction Data will be extracted by review authors (VB and FBH) from papers included in the review using the standardised data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details regarding: Citation details of the study Trial settings (i.e. hospital, community, outpatient) Inclusion and exclusion criteria Participant details (descriptive characteristics, i.e. age, sex, condition, sample size and number of trial drop outs) Method Interventions: description of the intervention, duration and dosage, comparison intervention/treatment plan Outcome measures: primary, secondary and adverse affects. If clarification is required then the authors will be contacted and the third reviewer will have final discretion regarding inclusion. Data synthesis Results from studies with similar designs will be collated using RevMan software to achieve a meta-analysis. Authors will be contacted to obtain any missing data that will inform the inclusion or exclusion of the study or that will influence the meta-analysis. Where possible, data will be viewed from an intention-to-treat perspective and missing data assumed to be negative or adverse. Due to potential for variation in conditions causing balance disturbance within the review, the heterogeneity of the results may be significantly influenced. Heterogeneity between studies will be estimated using I2 and sensitivity analysis. Subgroup analysis will be provided to determine whether outcomes vary according to condition and severity of falls experienced, if data is available. Where possible, subgroup analysis of the intervention will be conducted and include: type of intervention (bespoke systems versus commercial gaming consoles), frequency (number of sessions per week), and intensity (total hours of intervention). Conflict of Interest There is no conflict of interest. Acknowledgements The author (VB) has been funded by the Nottingham University Hospitals NHS Trust through a Pump-Priming award to instigate and develop research within the Trust. Acknowledgments must also be made to the University of Nottingham and the NIHR for previous support and funding to develop the author.