Gait Rehabilitation . . .One Step at a Time

By Claire Z. Kalpakjian, Ph.D.,
University of Michigan Model SCI Care System
From SCI access, a publication of the University of Michigan Model Spinal Cord Injury Care System

Although more and more money funding rehabilitation research goes to “basic science” work in neuroscience and nerve regeneration, many studies continue to focus on “restoration” and rehabilitation. Significant progress has been made in gait rehabilitation. And some of that progress has taken place right here at the University of Michigan.

It was gravity that started Dan Ferris, Ph.D. on the road that led him to the University of Michigan and his Human Neuromechanics Laboratory. Recently Ferris, Assistant Professor in the Departments of Movement Science and Biomedical Engineering at the University of Michigan since 2001, gave a tour of his laboratory where gait rehabilitation after SCI is making strides.

Upon entering his laboratory, it is clear there is some serious engineering is going on. The lab, occupying 1,200 square feet, has 10 computers, a tool bench, electronics station, and outlets aplenty – in fact, there is one every foot along the walls.

Ferris’ work is based on a simple principle: when a spinal cord injury occurs, the body does what it was designed to do – it adapts. In other words, it forgets walking and adapts to sitting. Gait retraining helps the body to remember how to walk.

Although standing frames can have a number of health benefits, they do not let the body practice walking. Locomotor training was first tested in the 1980’s on cats whose spinal cords had been cut. It turned out that gait retraining was relatively easy in cats (and rats) because locomotor control is more centralized in their spinal cords. But for humans, locomotor control is more distributed in the brain and spinal cord, making gait retraining a more difficult task.

So Ferris took two old ideas – artificial pneumatic muscles and orthoses – and combined them in a unique way to create pneumatically powered lower limb exoskeletons. In other words, robotic braces for the legs. Pneumatic muscles are like specialized balloons. When you pump air into them, they inflate and contract like human muscles. The hope is that these will help train the muscles to work on their own again.

Ferris says that his work in gait training is a natural extension of the work being done in spinal cord regeneration because once those nerve connections are reestablished, the body must relearn how to walk.

From a rehabilitation perspective, one of the most important ideas driving Ferris’ work is empowerment. The exoskeletons and exercise machines that Ferris works on in his lab are designed to let the user have control over the rehabilitation. An added bonus of the exercise machines is that people can use them independently at home.

Ferris has three important points for people with SCI to keep in mind when thinking about his and others’ research in gait retraining:

1. Few clinics have the equipment and specially trained staff that are necessary to produce good results. Until rehabilitation practice and insurance join in these efforts, widespread use of this technology will not occur.
2. Research in gait training is positive overall, but there have been some results showing little benefit. This may be because therapists are not always similarly trained in a highly specialized technique. As such, different results can occur between studies.
3. Knowledge learned from these studies can be used not only to help people right now, but also those who will benefit from advances in molecular biology and spinal cord regeneration in the future.

Ferris’ lab boasts two engineers, two physical therapists and two kinesiologists (those who study human movement). Their mission is to understand the complexities of physiology and technology -- not an easy job. But Ferris is optimistic that one day people with SCI and clinicians will have a wide array of devices and exercise machines that will greatly improve the rehabilitation process.