Kennedy Krieger researchers believe tool has potential to help patients relearn to walk after brain injury
In a step towards improving rehabilitation for patients with walking impairments, researchers from the Kennedy Krieger Institute found that non-invasive stimulation of the cerebellum, an area of the brain known to be essential in adaptive learning, helped healthy individuals learn a new walking pattern more rapidly. The findings suggest that cerebellar transcranial direct current stimulation (tDCS) may be a valuable therapy tool to aid people relearning how to walk following a stroke or other brain injury.
Previous studies in the lab of Amy Bastian, PhD, PT, director of the Motion Analysis Laboratory at Kennedy Krieger Institute, have shown that the cerebellum, a part of the brain involved in movement coordination, is essential for walking adaptation. In this new study, Dr. Bastian and her colleagues explored the impact of stimulation over the cerebellum on adaptive learning of a new walking pattern. Specifically, her team tested how anode (positive), cathode (negative) or sham (none) stimulation affected this learning process.
"We've known that the cerebellum is essential to adaptive learning mechanisms like reaching, walking, balance and eye movements," says Dr. Bastian. "In this study, we wanted to examine the effects of direct stimulation of the cerebellum on locomotor learning utilizing a split-belt treadmill that separately controls the legs."
The study, published today in the Journal of Neurophysiology, found that by placing electrodes on the scalp over the cerebellum and applying very low levels of current, the rate of walking adaptation could be increased or decreased. Dr. Bastian's team studied 53 healthy adults in a series of split-belt treadmill walking tests. Rather than a single belt, a split-belt treadmill consists of two belts that can move at different speeds. During split-belt walking, one leg is set to move faster than the other. This initially disrupts coordination between the legs so the user is not walking symmetrically, however over time the user learns to adapt to the disturbance.
The main experiment consisted of a two-minute baseline period of walking with both belts at the same slow speed, followed by a 15-minute period with the belts at two separate speeds. While people were on the treadmill, researchers stimulated one side of the cerebellum to assess the impact on the rate of re-adjustment to a symmetric walking pattern.