A balance disorder can be as minor as a brief dizzy spell when you change positions — called benign positional vertigo — or it can involve recurrent dizzy spells, like Meniere’s or a type of migraine called vestibular migraine. Some patients may have balance disorders because of medications, infection, injury, or another medical condition. Balance problems can also develop with age. One recent study estimated that 35 percent of US adults age 40 and older have vestibular dysfunction. Loss of inner ear function combines with declining strength and sensation to cause falls — which 1 out of 3 adults over 65 suffer each year. Falling — and the fear of falling — can impair overall fitness and mobility.
The main organs of the vestibular system are in the inner ear; they act much like a Wii controller to sense your motion and position in space. the brain integrates this information from the inner ear along with sensations from the rest of the body, hearing, and vision, to provide an overall picture. the vestibular system also sends information out. It stimulates eye movements that keep vision stable even as the head is moving, and controls postural reflexes that keep your body in equilibrium when upright.
The Jenks Vestibular Physiology Laboratory at the MEEI offers patients a comprehensive series of tests designed to isolate different aspects of the vestibular system. Rauch says that while the tests provide important information, “a disturbance of balance is a sensation that patients have, and you can’t measure a sensation.’’ at some level, doctors need to rely on a patient’s descriptions of their subjective experience.
Medications can reduce the symptoms of dizziness and nausea. in rare cases such as severe Meniere’s disease, surgery on the vestibular organs is needed. For many patients, the primary treatment is physical therapy, which may include learning to avoid falls, improving their strength and coordination, or a special program of vestibular rehabilitation, which helps them compensate for their missing or damaged balance system.
“Balance conditions are life-changing for many patients,’’ says Rauch. Learning to live with a compromised vestibular system is like learning a new language; the brain must recalibrate to a more limited range of information.
Scientists are also creating devices that could supplement a damaged vestibular system. One fairly simple device developed by Conrad Wall at MEEI’s Jenks Laboratory is a belt that senses a person’s posture and vibrates when they move too far out of balance. James Collins, a researcher at Boston University, has developed insoles that vibrate randomly at a level below human detection, which help to enhance the foot’s ability to detect sensations. Collins says that the technology, now being developed by the Wyss Institute for Biologically Inspired Engineering at Harvard, can give elderly people the balance and coordination of much younger adults.
Daniel Merfeld, a balance researcher at MEEI, is collaborating with Richard Lewis, an otoneurologist and researcher there, on a long-term project to develop a vestibular prosthesis, which would help replace the vestibular system in the inner ear in the same way that a cochlear implant replaces hearing in people with deafness. the principle is the same, but rather than converting sounds into electrical signals that are delivered to the brain through auditory nerves, the device would sense positional information from the head and convert that into signals to the vestibular nerves. so far the device is being tested in animals, and the researchers hope to bring the device into human trials in the next few years.
At MIT’s Man Vehicle Laboratory, researchers have been studying the vestibular effects of space travel, during which the normal forces of gravity are altered, which can cause disorientation and motion sickness. the Jenks Laboratory is also conducting basic research in animals and humans to understand how the vestibular system works. To do that, Merfeld explains, “we have to move our subjects.’’ the lab contains a veritable amusement park of contraptions that spin, slide, and swing their subjects to isolate different aspects of motion. all of this research aims to give doctors a better understanding of a sense that is critical to our daily lives but is often overlooked.
For people like Winslow, the importance of balance is no longer in the background. in order to alleviate his disabling vertigo, he has had to undergo treatments that lessen the function of one of his inner ears. and while physical therapy has helped him cope, his life has changed.
“It affects everything,’’ he says.
© Copyright 2010 Globe Newspaper Company.