Monday, April 09, 2007
By David Brinn April 08, 2007
A Technion Institute computer science researcher has devised an auditory feedback system which enables patients with multiple sclerosis (MS) to improve their gait.
Professor Yoram Baram said that the apparatus, which is an updated version of a virtual reality visual feedback apparatus he developed a decade ago, can also help Parkinson's disease patients walk better.
"Our earlier system was based on a visual feedback device - this one is an auditory feedback device that has a visual element to it," he explained to ISRAEL21c. "The apparatus we built is the size of a Walkman and is worn on a belt. It measures body movement, processes it using a computer and then sends a signal to the ears through earphones."
According to Baram, auditory feedback helps patients walk at a fixed pace because gait quality is expressed through a series of sounds that a person hears while walking.
"The user hears a ticking sound which is synchronized to his steps, rather than hearing a rhythm track and having to respond to it. Now he hears his own steps. If the patient doesn't have a balanced, steady walk, all he needs to do is produce his own rhythm as an auditory cue," he said.
The 400,000 Americans suffering from MS, lack a simple, but integral element that healthy people have to control their walking - sensory feedback from muscle nerves, which report on muscle control, telling them if they are using their muscles correctly or not.
"This feedback is damaged in Parkinson and MS patients and the elderly. Parkinson's results from the production of dopamine in the brain which affects muscle function, and MS develops when the patient's immune system attacks the white matter nerves in the brain," said Baram.
The most common neurological disorder diagnosed in young adults, MS affects eyesight, mobility, bladder and bowel control, and causes chronic pain and dizziness.
Together with Prof. Ariel Miller of the Technion's Rappaport Faculty of Medicine and the Multiple Sclerosis and Brain Research Center at the Carmel Medical Center in Haifa, Baram examined the influence of the auditory/visual apparatus on the gait quality of MS patients. Their work was recently published in the important scientific publication, Journal of the Neurological Sciences.
In the study, on-line (device on) and residual short-term therapeutic effects on walking speed and stride length were measured in 14 randomly selected MS patients with gait disturbances. The results showed an average improvement of 12.84% on-line and 18.75% residually in walking speed. Average improvement in stride length was 8.30% on-line and 9.93% residually. According to Baram, the improvement results are particularly noteworthy when compared with the lack of change in healthy control subjects.
Baram says that the virtual reality visual feedback apparatus developed 10 years ago influences more stride length while the auditory apparatus influences walking speed. Now that both devices have been integrated, the patient wears the visual feedback apparatus on his eyes and the earphones are connected to it.
"Our findings also raise the possibility of understanding the processes that go on in the brain when processing the sensory information reaching it," he adds.
Baram recently returned to the Technion after spending a year in the US conducting research on the device with MS and Parkinson's patients at the Neuroscience Institute at the University of Cincinnati, as well as at the Parkinson's Institute at Stanford University in California.
"The device has been tested at all those places and the preliminary results are very good. We received very positive response from our colleagues at those institutions," he said.
Baram, who holds a PhD in electrical engineering and computer science from MIT, once designed a mechanism for the U.S. National Aeronautics and Space Administration that helped helicopters navigate at low altitudes around obstacles such as electrical poles and trees. Several years after his work for NASA he was watching television and heard a man with Parkinson's describe how he found it easier to walk on a tiled floor since the grid pattern made the image more stable.
Baram made a connection between his work for NASA and the Parkinson's patient's description. The design Baram later used for the visual device was based on the idea that optical images of fixed objects help people stabilize themselves, whether they are walking or flying a helicopter.
One patient who tested the audio/visual system was Jack Rose, a 77-year-old Parkinson's patient from outside Cincinnati. He told The Cincinnati Enquirer that the grid "makes you feel like you have something to step over," which makes it easier to take that first step.
At the neurology clinic, Rose and other study subjects walked on a special mat equipped with sensors that measure how fast they walk and the length of their steps.
The information was fed into a computer so researchers could track people's progress. Rose's data showed his steps were short and close together at the start of the study session, and longer and faster at the end of it, indicating his progress from a slow shuffle to an easy, natural stride.
According to Baram, the main reason for developing the auditory element of the device is because many of the patients are also handicapped by poor eyesight, for which the audio device compensates.
"Some people don't see very well, and this provides an auditory channel option. In addition, the rhythmic sound device is less expensive than the relatively costly visual display," he said, adding that the combined device would probably cost in the area of $1,000.
Now ensconced back at the Technion, Baram is concentrating on conducting further testing of the auditory/visual device and looking forward to the day when MS and Parkinson's patients will be walking steadier.