Timothy C. Hain, MD • Page last modified: February 13, 2016
|Virtual reality scene used in the laboratory of Dr. Emily Keshner|
Virtual reality is a promising method of treating people with inappropriate visual dependence. It seems a lot more likely to work than smearing Vaseline on ones glasses (see unusual treatments page). Persons with visual dependence are the people who get sick from looking at ceiling fans, or going to the Omnimax.
VR training is usually a variant of habituation. The hypothesis is that repeated exposure to visual stimuli will reduce the intensity and duration of the response. This is a very reasonable hypothesis.
Occasionally, VR is used as an attempt to cause adaptation of the vestibular ocular reflex. For example, There has been some preliminary work done by Viirre, suggesting that virtual reality may help assist in increasing abnormally low vestibular ocular reflex gain (Virre and Sitarz, 2002). We find this idea dubious, as we think that walking around in the real world is a far more capable method of changing VOR gain than wearing some goggles for 30 minutes once/week.
Virtual reality is no longer new, but there are few studies that bear on this intervention, and clinical use of VR for visual vertigo is very unusual. The human literature to date is presently weak, largely consisting of single case reports, and small group studies of questionable interventions or without any control group.
Pavlou et al (2012) suggested that it was very helpful. They studied 16 patients with unilateral peripheral vestibular disorders, randomly allocated to VR or conventional. The duration 4 weeks, twice/week with home exercises. They reported At final assessment, significant that the VR groups showed a 59.2% and 25.8% improvement respectively compared to 1.6% for the "static" control group.
Meldrum et al (2015), reported in a physical therapy journal, that VR were "not superior to conventional balance exercises". They used an "off the shelf" virtual reality gaming system. We find the general implication of this report, that VR is equivalent to "conventional" vestibular rehab, dubious at best. We don't see that "off the shelf gaming systems" are equivalent to VR devices designed for vestibular reality. One would also think that a properly designed device would need to incorporate visual-vestibular conflict as well as anchors (Chang and Hain, 2008). This article seems to us to have the effect of protecting the physical therapy worlds conventional treatment with the cost of reducing interest of more novel treatments.
Suarez et al (2006) reported that 26 elderly unstable patients were treated with for 6 weeks "a virtual-reality system that changes sensory information (visual, vestibular, and somatosensory)", and reported improvement of balance. The lack of a control group limits the significance of this report.
The virtual reality that is easily available in 2015 usually involves wearing a head-mounted system, or a video game system. This implementation is crude, has no link between head movement and visual movement, and one might as well be wearing a lampshade on one's head as far as the utility for habituation. With newer devices that incorporate head movement sensors, it seems feasible to imagine more capable systems that can provide visual-vestibular mismatch.