‘Smart cane’ could help flag falling risks more quickly
Two Vanderbilt engineers have developed an instrumented cane that can analyze gait to determine the risk of falling while still providing support.
Nilanjan Sarkar, professor of mechanical and computer engineering, says the “IntelliCane” can quantitatively calculate falling risk as accurately as a physical therapist can with their own eyes.
Dizziness and balance problems are significant and costly public health issues. In the United States, every year one out of three adults over 65 years of age falls and the statistic climbs to one out of two after age 80. Serious falls can lead to hip and other bone fractures, brain injury, loss of independence and even death. The cost of treating injuries from falls is estimated at $34 billion annually.
The problem is not restricted to the elderly. Illnesses that cause balance disorders range from ear infections, head injuries and poor blood circulation to Parkinson’s, spinal stenosis and stroke, and these patients also could benefit from such a device.
“When I realized how big this problem was, we started searching for available solutions,” Sarkar said. “Initially, my thought was to design something to prevent falls, but after more thought and a little experimenting we quickly realized that this was not practical. The next best thing was to determine how to reliably estimate the fall risk so that intervention can be applied when a person’s risk gets so high that they could fall at any time.”
Physical therapists estimate falling risk by observing the patient walking back and forth between two lines under different conditions—slow and fast, looking right and left, stepping over obstacles, blindfolded, and up and down steps among them. The therapist uses a standardized rating scale to evaluate patient steadiness for each task and combines the ratings into an overall risk estimate.
But this test cannot always capture a patient’s full experience throughout the day, or from day to day, or within their usual environment. Nor can it capture problems the therapist may be unable to see.
Sarkar and Joshua Wade, a staff research scientist at Sarkar’s Robotics and Autonomous Systems Lab, wanted to develop a tool that could help therapists collect much richer data about their patients’ gaits as they went about their everyday lives, enabling therapists to intervene more quickly if needed.
Most current research in this area requires patients to place sensors on their body or in their shoes, which the researchers say isn’t ideal.
“Body sensors require a significant extra effort on the part of patients. We wanted an approach that was as easy as possible for people to use,” said Wade, who started working on the project when he was a graduate student. “We decided to instrument a cane because it is familiar. Most people with balance problems already use a cane, and the only thing extra that they have to do is plug it in at night.”
The engineers rigged an off-the-shelf offset cane – which has a J-shaped handle – with inertial and force sensors connected to a wireless microcontroller that provides real-time data on use as the person walks. An algorithm analyzes the sensor data and pulls out information about the steadiness of the user’s gait.
With a workable prototype, the engineers tested the system with nine patients. First, they asked the patient to walk around using the IntelliCane. Next, patients participated in a standard risk assessment procedure called the Dynamic Gait Index in the presence of a physical therapist, who scored their performance. After analyzing the cane data, the researchers determined that they could predict each patient’s DGI score with a high degree of confidence.
“I think it is quite innovative,” said Patricia Fleming, a physical therapist at Vanderbilt University Medical Center who participated in the test. “Many people don’t have access to a sophisticated gait lab, so a device such as this could augment what we do in the clinic.
“Almost everyone who comes to the neurological clinic where we work has a balance problem and many of them use a cane. So, we think it’s exciting to be part of this project,” Fleming said.
Sarkar and Wade are convinced this approach could have multiple benefits. For people with balance problems who use the cane regularly, it may be able to detect when users’ sense of balance begins to deteriorate and report this to physicians. The basic idea also could be applied to other devices such as wheeled walkers and crutches, they said.
With more advanced analysis, the IntelliCane might be able to provide enough detail to enable doctors to diagnose specific diseases that affect a person’s sense of balance. For example, Parkinson’s might alter a person’s gait in ways that are detectably different from multiple sclerosis, they suggested.
The Vanderbilt Center for Technology Transfer and Commercialization has applied for a patent on the technology, and Sarkar and Wade have formed a company called Adaptive Technology Consulting to commercialize it.