Study’s goal: to help patients walk after stroke

Sangeetha Madhavan (left) and assistant Tai Tri Nguyen demonstrate gait training for a study to improve recovery from stroke. Photo: Roberta Dupuis-Devlin/UIC Photo Services

“After a stroke, almost 60 percent of people are not able to walk independently in their community — and there are currently 6 million stroke survivors in the U.S.,” says UIC researcher Sangeetha Madhavan.

Madhavan, assistant professor of physical therapy and director of UIC’s Brain Plasticity Lab, is working to help them.

In her research, funded by a $1.5 million grant from the National Institute of Child Health and Human Development, Madhavan will test whether brain stimulation combined with gait training can improve patients’ ability to walk after a stroke.

“Improving their ability to walk would have an enormous impact on their quality of life,” she said.

Madhavan and her colleagues are studying how the brain changes in response to stroke and tap into its potential to help in recovery.

Scientists approach rehabilitation in different ways, she said. The most common method is to train muscles and re-teach walking, hoping that the brain will relearn how to control those functions.

Madhavan’s approach is top-down: stimulating the brain to make it more responsive to the therapy the patient will receive.

She will use a technique called transcranial direct current stimulation, or tDCS, which passes a low level of current through the motor area of the brain that controls the legs.

For the study, people 50 or older who have had a stroke will receive gait training on a treadmill.

The treatment group will receive brain stimulation before gait training. The electrical stimulation will be administered in combination with motor training of the ankle, because people trying to walk after stroke have difficulty flexing their ankle on the affected side.

The control group will receive only gait training, three times a week for four weeks.

The study subjects will be evaluated at the end of the four weeks and again three months later. Their walking speed and other clinical and quality-of-life measures will be assessed.

In addition, researchers will examine the physiological function of the cerebral cortex to see if brain plasticity changed after training. The study will use noninvasive methods, such as transcranial magnetic stimulation, to compare the activity of the affected and unaffected areas of the brain.

“After stroke, there is an imbalance in cortical excitability, with areas of the brain where the lesion is being less active,” Madhavan said. “We predict that activity in these areas will increase after the brain stimulation-walking intervention, and that the imbalance in symmetry is restored. This balance in cortical excitability is necessary for functional recovery.”

Because people with stroke differ in how they respond to therapy, Madhavan said, studying brain activity “gives us a way to understand why one individual changes differently from another.”