Neural degeneration with age and disease is a recognized and critical problem in health. Despite the significant problems associated with neural degenerative diseases and effects of aging, there remains a lack of effective treatments. An important neural system used daily is the vestibular system. The vestibular system provides continual information on our location in space and is integral to balance, locomotion, daily activities and quality of life. Our lab and others have demonstrated that with increasing age there is a loss of vestibular function that is associated with increased incidence of falls. In fact, falls are the leading cause of injury and death in older Americans (CDC). Older Americans experience 36 million falls per year resulting in 3 million emergency room visits, 700,000 hospitalizations and 32,000 deaths resulting in an estimated $50 billion in annual healthcare costs. Since falls in elderly individuals are associated with greatly increased mortality, reducing fall risk is an essential area to target for healthy aging. Since vestibular function is inherently involved in balance and gait, dealing with age related vestibular loss is an essential component of reducing fall risk. Similarly, patients with vestibular loss have reduced quality of life and increased risk of falls.
Our lab was the first to demonstrate that age related reductions in ocular torsion, a vestibular ocular reflex indicative of otolith function, are associated with increased postural sway in a large group of individuals (N=151) from 21-92 years. Our lab is also the first to demonstrate that subperceptual levels of random electrical stimulation, termed stochastic resonance, are able to improve ocular torsion, indicating improved otolith function, to compensate for age-related vestibular loss.6 Our lab as well as others have also demonstrated that the use of this stimulation can improve static balance and gait in a range of populations. Therefore, a neuromodulation device that could improve balance and gait and reduce fall risk would greatly improve quality of life in aging and reduce mortality. Currently, there are limited treatment options available that can compensate for vestibular loss. A novel neuromodulation treatment is clearly needed. However, current data in this lab and others have only examined the response in the lab over relatively short periods. A recent study found that 3 hours of stimulation improved static balance and this improvement lasted post stimulation for up to 4 hours. These data suggest that this stimulus could be used as a novel rehabilitation device. However there still remains several gaps in knowledge:
1. Do the improvements seen in one system translate to other systems? (i.e., if the investigators see improvement in vestibular ocular reflex, will that translate into improvements in static balance and gait)
2. Do these improvements in static balance translate into gait improvements?
The overall purpose of this study is to investigate whether low level (sub-perceptual) electrical stimulation produces improvements in vestibular function (balance system) that translate into improved balance and gait.
A. Objectives The goal of this study is to determine the cross-modality effectiveness of improving vestibular function on static balance and gait in a population of older individuals with verified reduced vestibular function.
B. Hypotheses / Research Question(s) The overall hypothesis is that stimulation of the vestibular system with extremely low level (subperceptual) electrical signals via surface electrodes will produce immediate improvements in vestibular function that will also translate into improve static balance and gait in older individuals.
