Conventional Versus Virtual Reality Based Vestibular Rehabilitation

Unilateral vestibular disease results in vertigo, dizziness, dysequilibrium and gait problems. Recovery results from a process known as vestibular compensation where visual and proprioceptive inputs are upregulated, or remaining vestibular function is recalibrated and utilised more effectively (Curthoys, 2000). Patients who do not compensate remain significantly impaired. They benefit from specialised assessment and treatment techniques collectively referred to as vestibular rehabilitation (Hillier and McDonnell, 2011). This form of rehabilitation has its roots in the empirical work of Cawthorne and Cooksey, who in the 1940's first documented the important role of exercise in recovery after a vestibular injury (Cooksey, 1945) and more recently in studies investigating vestibular adaptation (Schubert et al., 2008). Vestibular rehabilitation programs can be considered as motor learning programs and thus require practice and feedback. In conventional rehabilitation it is difficult for patients to gain feedback of performance performing balance exercise which can be repetitive and boring. Force plate technology has been used in the clinical setting to provide visual and auditory feedback and has shown some promising results (Teggi et al., 2009). Virtual reality, defined as 'a high-end-computer interface that involves real time simulation and interactions through multiple sensorial channels' (Burdea and Coiffet, 2003) is also being investigated in laboratory settings. There is some support for the use of virtual reality in vestibular rehabilitation (Viirre and Sitarz, 2002) but these technologies are presently prohibitively expensive and are not universally available. They require considerable therapist time and are unlikely to be used with the frequency that is required for motor learning (particularly in vestibular rehabilitation where most programs entail daily exercise). Recent developments in the gaming industry have resulted in the Nintendo Wii ® Fit Plus, which combines a force platform with an accelerometer to provide visual and auditory feedback of subjects' centre of gravity during virtual reality exercises and games. It stimulates movement and perturbs balance in order to retrain it. Use of this low cost gaming system could easily be adapted to meet the requirements of a vestibular rehabilitation program. The system allows for accurate monitoring of use in terms of time and frequency which is an area that has proven difficult to monitor in both research and clinical applications due to inaccurate patient recall. It is fun to use and therefore may be motivating patients. The rehabilitation community is beginning to investigate this technology in the area of balance retraining (Nitz et al. 2009). Anecdotal reports indicate the Wii is being used in vestibular rehabilitation (Hain, 2011) but as yet no randomised controlled trials exist.

It is important to measure the effect of this technology which can easily be incorporated into the home environment and compare it to conventional treatment before it can be recommended for use. In tandem with this is also important to gain some insights into patient satisfaction with both treatments.

Aim To compare the outcome from conventional vestibular rehabilitation to virtual reality based vestibular rehabilitation in the treatment of unilateral vestibular disease.

Objectives To compare the effect of conventional vestibular rehabilitation and virtual reality based rehabilitation on gait.

To compare the effect of conventional vestibular rehabilitation and virtual reality based rehabilitation on subjective complaints of dizziness/vertigo.

To compare the effect of conventional vestibular rehabilitation and virtual reality based rehabilitation on balance.

To compare the effect of conventional vestibular rehabilitation and virtual reality based vestibular rehabilitation on dynamic visual acuity.

To quantify patient satisfaction with conventional and virtual reality based vestibular rehabilitation.

Trial design

The study design will be an assessor blinded randomised controlled trial. There is moderate to strong evidence in the literature for the efficacy of vestibular rehabilitation, therefore a "no" treatment group is not deemed ethical.

Participants

Patients attending the otolaryngology and neurology outpatient clinics in Beaumont Hospital or the Royal Victoria Eye and Ear Hospital will be invited to participate in the trial.

Sample Size Calculation.

Allowing for a 10% drop out, a maximum of 48 participants will need to be recruited for each group (at 80% power to detect p<0.05 on all outcomes). A two year recruitment period is required.

The inclusion criteria will be;

• Clinical diagnosis of peripheral vestibular dysfunction and no other neurological deficit (confirmed where possible with vestibular function testing; canal paresis >20%).
• One of the following subjective complaints indicating a failure of vestibular compensation; disequilibrium, gait instability, vertigo/dizziness, motion sensitivity.
• Not taking medication for vertigo or willing to discontinue with permission from consultant physician.

The exclusion criteria will be;

• Bilateral peripheral vestibular pathology.
• CNS involvement.
• Fluctuating Symptoms (Meniere's disease, migrainous vertigo) or active BPPV.
• Other medical conditions in the acute phase (orthopaedic injury).
• Previous vestibular rehabilitation.
• Pacemaker, Epilepsy (as per Nintendo Wii Guidelines).
• Unwilling or unable to use a Nintendo Wii.

Randomisation

Following baseline assessments participants will be randomised to one of two groups;

1. Conventional vestibular rehabilitation
2. Virtual reality vestibular rehabilitation A third party (not involved in the day to day running of the trial) will use an online randomisation program to assign participants to either conventional treatment or virtual reality treatment in advance of recruitment. The treating physiotherapist will be informed of group allocation after consent has been obtained and after baseline assessments are completed.

Intervention

Based on current evidence in the literature a time frame of up to 6 treatments over 8 weeks will be provided. The interventions for both groups are based on six identified core elements of vestibular rehabilitation used in current clinical practice- education, relaxation, adaptation exercises, habituation exercises, balance and gait retraining and re-conditioning (Meldrum and McConn Walsh, 2011). Programs will be customised to each participant depending on their presenting symptoms and impairments, and will be progressive. All participants will be asked to perform a home exercise program daily for 30 minutes. Where participants are deemed at risk of falling, they will be provided with the necessary preventative instructions. Participants in the virtual reality group will be instructed in the use of the Nintendo Wii ® and will be given one on loan. They will be provided with a customised program which is the virtual reality equivalent of conventional exercises. Those in the conventional group will be provided with a foam balance mat. Participants will be seen weekly for re-assessment, progression of exercises and advice.

Measurement of compliance with home treatment

All participants will be provided with a diary to record compliance with the home exercise program. The Nintendo Wii ® fit plus records type, duration and frequency of exercises and this will also be used as the record for the virtual reality group.

Data will be entered and coded in Microsoft Excel and statistical analysis will be performed using PASW and Stata 11. Intention to treat analysis will be performed. Data will be examined for normality and if a normal distribution is observed t-tests, and an ANOVA model will be used for analysis of interval data with an adjustment for baseline values. The non-parametric equivalent will be used where data are not normally distributed or are non-parametric. Differences from baseline will be calculated for primary and secondary outcomes within groups and between groups at each time point. A significance level of p<0.05 will be set. Effect sizes for within and between groups comparison will be calculated.