Efficacy of a Mechanical Chair for Treatment of Benign Paroxysmal Positional Vertigo (BPPV)

Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo (Bhattacharyya et al., 2017). BPPV is estimated to affect 900 out of 10,000 people annually (Kerrigan et al., 2013) with healthcare costs approaching $2 Billion (Bhattacharyya et al., 2017). We have shown that patients with BPPV rate the impact on their quality of life similar to patients with macular degeneration, hepatitis B, and HIV/AIDS (Roberts et al., 2009). BPPV occurs when calcium carbonate crystals from one part of the inner ear balance system (utricle) become displaced into other parts of the inner ear balance system (semicircular canal). Normal head and body movements cause movement of the crystal debris within the semicircular canals. This movement causes changes in stimulation of the sensory structures of the semicircular canals that result in vertigo, nausea, imbalance, and even falls. It is well established that BPPV affects the posterior semicircular canal 80% of the time, the horizontal canal 15% of the time and the anterior canal 5% of the time.

There are established methods that have been proven to be effective in treatment of BPPV with randomized controlled trials (Hilton \& Pinder, 2014). Each of these methods involves moving a patient's head and body through specific positions to remove the debris from the involved canal. However, many of these patients require multiple treatments and there is a group of patients with BPPV that do not respond to these treatments and for whom surgical options are ultimately considered. Further, patients with hip or neck problems, spinal issues, and even obesity are often unable to be placed in or move through the required positions.

A motorized chair was developed to improve treatment consistency and efficacy and broaden the group of patients who could receive appropriate treatment (Nakayama \& Epley, 2005). Although the motorized chair was effective and there are no known reports of adverse events, it was also very expensive. Few facilities were able to purchase the motorized chair so the anticipated impact on helping patients with BPPV was never realized. The motorized chair is no longer being manufactured. A mechanical chair for assessment and treatment of BPPV was also described around the same time as the motorized chair (Richard-Vitton et al., 2005). This is referred to as the TRV chair which are the initials of the inventor.

This mechanical chair has been used in several countries including across Europe and in China. Wang et al. (2014) reported they were able to clear various types of BPPV in 202 of 208 (97.1%) cases. The remaining six cases reported significant improvement. There was no control group in this study and the inventor is listed as an author. No adverse events were reported. West et al. (2016) completed a retrospective chart review of patients treated for BPPV in their clinic.Interestingly, they had both the TRV chair and the motorized chair. Some of their patients also underwent treatment with traditional methods which do not incorporate a specialized chair to help position patients. The authors concluded that specialized chairs (motorized or mechanical) are useful for treatment of BPPV, especially for more difficult cases. There are also some limitations with this report in that no control group was used and participants were not randomly assigned to a treatment type. Patients with a typical history of BPPV, and identified with the most common type affecting the posterior canal, were treated with the traditional methods first and then perhaps with a specialized chair. Other patients were treated with both types of chair. No adverse events were reported.

Specialized chairs do appear to offer some advantages over traditional methods of BPPV treatment. Reports in the literature suggest the specialized chairs are able to treat more difficult cases of BPPV. This should allow improved cure rates for the approximately 20% of patients that require multiple treatments using the traditional methods. Use of specialized chairs would also increase the number of patients who can be treated because there are no contraindications related to hip, spine, and mobility issues as there are for traditional methods of BPPV treatment. The mechanical chair (TRV chair) appears to offer all of the advantages of the motorized chair but at a lessor cost anticipated to be $65,000 compared to $100,000 for the motorized chair. One may speculate there is less maintenance required for a mechanical versus a motorized system and there is the fact that the currently described motorized version is no longer available for purchase.

The primary purpose of this project is to determine treatment efficacy of the motorized TRV chair for patients with BPPV. This information has not been published using a randomized controlled design. A secondary purpose of the project is to determine if the TRV chair is helpful in patients experiencing chronic symptoms of dizziness and unsteadiness who may have complaints suggesting positional vertigo but who fail to generate nystagmus (i.e. covert BPPV). If the TRV chair is more efficacious than traditional methods, our hope is that nearly all patients with BPPV will be able to be managed in a more efficient manner. This will decrease the impact of BPPV on health-related quality of life, could decrease falls related to BPPV, and should also decrease the burden of healthcare costs.