"Ipod-like" device to help correct balance disorders

Jul 13 2005

Researchers at Oregon Health & Science University's Neurological Sciences Institute and the University of Bologna have developed a portable "Ipod-like" device that can be used to help correct balance disorders. Scientists believe this new device, based on auditory feedback of balance, can be worn on the belt like a pager to provide regular therapy for patients with balance disorders, improving their day-to-day activities. The research is published in the current edition of the Archives of Physical Medicine and Rehabilitation.

"We believe this type of device can become an important tool in combating balance disorders associated with problems like vestibular loss diabetic neuropathy, or Parkinson's disease, where a person's ability to maintain balance is impaired," explained Fay Horak, Ph.D., a senior scientist at the NSI and senior author of the paper. "In fact, in early testing, research subjects with balance disorders who have used the device have shown significant improvement. We believe the nervous system can substitute auditory cues for missing or inaccurate sensory information from other senses important for balance, such as from sensors in the inner ear and from muscles and skin."

The balance feedback device acts much lot like a carpenter's level in alerting the subject to how much they are leaning outside of a predetermined central "safe-zone." The device is connected to a pair of headphones and hooked to the subject's belt. When activated, subjects receive audio cues to let them know how their body is balancing.

"Different tones and intensities tell subjects when they are leaning outside of their central safe zone," explains Marco Dozza, M.E., a graduate student in bioengineering at the University of Bologna who spent part of last year conducting human tests of the device in Horak's speciallydesigned balance disorders lab. "In addition, the sounds tell the subjects which way they are leaning so they can immediately correct the problem before they fall. For example, when subjects lean forward, they hear a high-pitched tone that becomes higher and louder the farther they lean forward. If subjects lean backward, they hear a low-pitched tone that drops and gets louder as they lean back. In addition, the tone becomes louder in the left ear when a subject leans too far to the left. The tone becomes louder in the right ear when the subject leans too far to the right."

To conduct this study, the researchers tested nine subject suffering from balance problems associated with bilateral vestibular loss caused by ototoxic medications, drugs that have a negative effect on the balance structures in the inner ear. When using the device, these subjects witnessed a marked decrease in sway area, meaning that they were less likely to lean far out of their safe zone. They also spent an increased amount of time within their safe area. Some subjects who were not able to stand on a soft cushion with eyes closed without the device were able to stand safely while using the balance feedback device.

One subject who has taken part in testing for the device is Fred Kawabata. The 65-year-old retired electronics engineer has balance problems associated with a reoccurring viral infection that affected his inner ear.

"It's as if my body isn't as fast as it used to be in providing feedback about my balance," explained Kawabata. "While maintaining balance is an automatic function for others, for me, some tasks require active thought about balance. During the testing, I found the device to be very intuitive in helping me correct balance issues more quickly."

Horak says follow-up studies are now required to determine how long the impact of balance training with the device lasts and how frequently balance training may be required.

"We are now testing how much the device works to help balance while walking," said Horak. OHSU's Neurological Science Institute is located on the university's West Campus in Beaverton. The NSI's mission is to advance our understanding of the brain and neurological disorders. NSI scientists use integrated and interdisciplinary approaches to expand knowledge about how the brain and nervous system function. Their goal is to translate new knowledge into innovative ways to diagnose, treat, cure and prevent neurological diseases and disorders.