December 1, 2008 Physical therapists used motion detector cameras to analyze how patients move on a specially designed split-belt treadmill--the belt is divided to move together or at independent speeds. When the legs move at speeds different from one another, the brain receives an error signal and the brain and nervous system use the feedback to adjust. The cerebellum recalls this message even after the treadmill stops and for a few minutes, stroke patients can walk easier.
Stroke patients often have to overcome a number of challenges before they can get back on their feet. Physical therapists are using a new tool to help patients not only retrain their bodies but also rewire their brains.
Two years ago, Terri Knudsen suffered a sudden, massive stroke while she was talking to a friend. "I noticed I was talking funny, like I had an accent, and she said it sounded like I was underwater," said Knudsen.
Knudsen lost mobility on her left side. She spent months relearning how to stand and how to walk.
Physical therapists are using a new tool to help patients like Knudsen regain an even gait.
Using motion detector cameras, physical therapist Darcy Reisman, Ph.D., an expert in biomechanics and movement science at the University of Delaware in Newark, Del., analyzes how a patient moves on a specially designed split-belt treadmill. The belts can run together, or therapists can program the belts separately.
Dr. Reisman says when a patient's legs move at two different speeds, the brain gets an error signal. Next, the patient's brain and nervous system use the feedback to adjust. The cerebellum is the part of the brain that controls coordination. It remembers what it has learned even after the treadmill stops. For just a few minutes, stroke patients have an easier time on solid ground.
"You notice immediately that you want to take a bigger stride," Knudsen said. "It was a definite carryover from the treadmill."
"There's the immediate effect that you get," said Dr. Reisman. "The problem is, of course, that it decays."
Dr. Reisman wants to know if additional treadmill therapy will help rewire the brain, resulting in longer periods of even walking -- and making the split-belt treadmill the first step towards a faster recovery for stroke patients.
ABOUT STROKES: A stroke is a type of cardiovascular disease that affects the arteries leading to and from the brain. When one of these becomes blocked, or bursts, blood and oxygen can't get to that part of the brain and it begins to die. Strokes can cause paralysis, affect language and vision, and lead to memory loss. Strokes kill nearly 163,000 people every year; it is the third leading cause of death, behind heart disease and cancer.
ABOUT MOTOR FUNCTION: Even a simple motor movement involves many different regions of the body, but the primary motor cortex of the brain is one of the most important. It sends out electrical impulses through nerve cells called neurons that control the execution of movement. Every part of the body is represented in the primary motor cortex; the left side of the brain controls the right side of the body, and vice versa. Certain diseases or brain damage can disrupt these basic functions. For instance, cerebral palsy is a disorder that affects body movement and muscle coordination because of brain damage, which interferes with messages from the brain the body, and vice versa.
HOW WE WALK: Walking is different from a running gait because only one foot at a time lifts off the ground. During forward motion, the leg that leaves the ground swings forward from the hip, like a pendulum. Then the leg strikes the ground with the heel and rolls through the toe in a motion similar to an inverted pendulum. The motion of the two legs is coordinated so that one foot or the other is always in contact with the ground -- a so-called 'double pendulum' strategy. The process of walking recovers about 60 percent of the energy expended thanks to the pendulum dynamics and the ground reaction force. The legs act as long levers that transfer ground reaction force to the spine.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.