Critical inner ear structures answer this question. But not always. A wearable device could restore the balance.
John A. Blumenfeld, a lawyer based in Clayton, Missouri, is missing something most people take for granted — a sense of balance. It's not just that he can't walk a tightrope without a net. It's that he has trouble walking anywhere that's not smooth, flat and well lit — a thick lawn, a slanting sidewalk, a dim hallway.
"Any time I'm walking, my main objective is to avoid falling," Blumenfeld says. "It's not an easy task because I feel unsteady. It's something that's always with me, and it's not pleasant."
He sought help from Joel A. Goebel, MD, director of the Dizziness and Balance Center at the School of Medicine. Goebel started Blumenfeld on vestibular rehabilitation exercises, which teach him to compensate for his loss of vestibular, or inner ear, function. But Blumenfeld also agreed to participate in the testing phase of a device that could some day help many people with balance disorders.
The device, worn on the head, alerts wearers that they are leaning so they can upright themselves — something people with healthy inner ear function usually do without thinking.
"We saw such a strong positive effect in our preliminary trial that the funding agency, the National Institutes of Health, recommended we move forward with a second, broader trial of the device," says Goebel, professor and vice chairman of the Department of Otolaryngology. "The first trial tested the device on people with complete vestibular loss in both ears. We believe that if we can help that group of patients, we can certainly help the larger group who still retain some vestibular function."
To stand, walk, run or ride a bike, people rely greatly on the sensory apparatus of the vestibular system located in the inner ears. Two million people in the United States live with chronic imbalance as the result of vestibular system malfunction. Imbalance interferes with daily life and increases the risk of falls, which can be deadly in those who are frail.
But people aren't completely dependent on the vestibular system for balance. When they lose some or all of its function, as Blumenfeld did, they can use other senses to tell them what's up and what's down. Visual cues from their surroundings and nerve signals indicating the position of their feet, limbs and torso can allow them to get around. But those balance strategies take continual conscious effort. Furthermore, vision can't help when it's dark, and soft surfaces can easily throw off a person's sense of what's underfoot.
Two years ago, Barron Associates Inc., a research and development company, approached Goebel about working with them to develop technology for preventing seasickness in naval servicemen. That morphed into a project to address balance problems in those with vestibular malfunction.
Goebel, along with two researchers at Princeton University and two technical experts from Barron, outlined a proposal that won a small-business innovation research grant from the NIH, a type of award that backs research with commercial potential. They put together a prototype device based on the theory that a tactile sensation, a touch, could become a substitute for the unconscious senses that normally keep people from falling over.
The early version of the device, admittedly a little cumbersome, consists of headgear wired to a computer. The headgear senses how many degrees from vertical the wearer's head inclines and through a connected computer communicates with four mechanical tappers on the sides, front and back of the head. The tappers very gently strike the wearer's head, tapping slowly for one degree of tilt, fast for two degrees and very fast for three degrees.
Blumenfeld was one of nine subjects who visited Goebel's balance lab to find out if that tapping could minimize falls. Clinical audiologist Belinda C. Sinks, AuD, supervises the lab and oversaw the test participants. She placed the volunteers on a platform that could freely tilt around a center point. A harness and support straps prevented them from falling over completely.
"The therapist tilts the platform this way and that way to see how you react," Blumenfeld says. "The headgear gives you a signal. It's a barely noticeable tap."
Blumenfeld says that he found the tests difficult. That's likely because he was part of a group that got tapped on the side of the head away from the direction of lean. That is, if he was tipping forward, the device tapped the back of his head, basically saying, "Lean toward me." The other group of test subjects got tapped from the direction of lean. When they leaned to the left, for example, the tapper on the left activated. For them, the tapping was a warning to lean away.
"That turned out to be much more intuitive," Goebel says. "When you are falling in a crowd and somebody catches you, they'll push you back. You move away from the pressure of their hand. That's the natural reaction."
For the second group, the device worked very well; they were able to avoid falling more often than the other group. When they did fall, it was after a longer time on the platform. And they were better able to use corrective movements of their ankles and hips to remain standing.
The company is now building a more compact version of the device, and Goebel has received funding for a second, more extensive testing phase that will include patients with a wider range of balance disorders. This study will determine whether performance improves over time and whether the benefit continues after patients stop using the device. Goebel believes a marketable product, a device incorporated into a hat or scarf, could be ready within the next two years.
For people like Blumenfeld, the balance-correction device could bring a welcome measure of confidence and freedom. "My wife and I used to like to go on tours, but we stopped traveling when I developed this problem," he says. "And two years ago I fell and needed a hip replacement because of the disorder. I want to do what I can to help research to ameliorate the problem for others."