Device Performs Balancing Act

Medical Device & Diagnostic Industry Magazine
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Originally Published MDDI October 2005

R&D Digest

By Maria Fontanazza

Researchers have created an auditory feedback device that can help fix balance disorders. It can be used for balance rehabilitation and athletic training. Oregon Health and Science University's Neurological Sciences Institute (Beaverton, OR) collaborated with the University of Bologna (Italy) on the work.

The device is customized for each user. The subject wears a set of headphones, which are connected to a linear accelerometer that hooks onto the person's belt. Different tones and volumes tell the subject how far he or she is moving away, in all directions, from the initial position. This allows a person to correct balance before falling.

“The earphones balance for left and right sway,” says Fay Horak, senior scientist at the Neurological Sciences Institute. “We use frequency for detecting forward and backward sway.” Horak is also a professor of neurology, physiology, and biomedical engineering at Oregon Health and Science University.

Specifically, a high-pitch tone gets higher and then louder the farther the person sways forward. Likewise, a low-pitch tone drops and becomes louder as the person leans farther back. Sound is increased in the left ear when the person is leaning to the left and increased in the right ear when the lean is to the right.

Right now the subject must be attached to a laptop. The team hopes to make the system smaller and completely wireless. “We'd like to be able to portably record the person's body sway so we can download the information on the computer independently,” says Horak.

Upon miniaturizing the device, they will need a digital card or chip that collects data for the subject to wear. The software also must be made user-friendly, and it needs to be sealed.

“[The information] must be downloadable so the therapist or physician can get information about the person's performance,” says Horak. “Then we need some software to analyze the data and interpret them for the clinician.”

Horak says the first application would be for physical therapists. The device would help them assess and improve patient balance in clinical practice. Later, it's possible that patients could take a system home for use as a prosthetic device.

Other uses include athletic training for sports like gymnastics and snowboarding. In fact, it might be used in any exercise where the person's trunk needs to remain vertical. Pilots could also use it in flight simulation to help orient them to gravity changes.

The researchers tested nine subjects who suffered from balance problems. The results showed that those using the device were less likely to sway out of a predetermined “safe zone.” More testing needs to be conducted to see which patient populations benefit from the device.

The research was published in the July issue of the Archives of Physical Medicine and Rehabilitation.

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