Stroke Patients May Benefit From Brain Stimulation
One of the most frustrating consequences of a stroke is losing function in your hands, arms, and legs. Researchers have found that noninvasive electric brain stimulation to both hemispheres can help stroke patients regain motor skills.
Stimulation is applied to both sides of the brain
According to Gottfried Schlaug, MD, PhD, director of the Stroke Service in Beth Israel Deaconess Medical Center’s Department of Neurology and associate professor of neurology at Harvard Medical School, “both sides of the brain play a role in recovery of function” after an individual has a stroke. Thus a treatment approach that addresses both hemispheres seems a logical choice.
In this latest study, Schlaug and his colleagues showed, for the first time, that stroke patients who were administered electric stimulation (specifically, bihemispheric transcranial direct current stimulation, or tDCS), along with both physical and occupational therapy, had a threefold better improvement in motor skills when compared with patients who received a placebo stimulation and physical and occupational therapy.
In a healthy brain, the motor cortex in both hemispheres interact in a complex dance that allows individuals to perform one-sided activities, such as writing or stirring a pot of soup. A stroke, however, changes the dance card, and the interaction between the two sides of the brain is altered.
When the motor cortex in the side of the brain not affected by the stroke begins to exert an unbalanced influence on its counterpart on the damaged side of the brain, explains Schlaug, there is increased inhibition on the stroke-damaged side. In response, the remaining intact areas of the motor cortex attempt to increase activity to facilitate recovery.
Enter tDCS, an experimental therapy that involves sending a mild electrical current to the brain through the scalp and skull. Previous research had shown that tDCS improved motor function when it was used to either the damaged or undamaged side of the brain. Schaug and his team decided to apply stimulation to both sides of the brain while patients were also in physical and occupational therapy.
Twenty patients who had experienced an ischemic stroke at least five months before entering the study were divided into two groups. Ten patients received 30 minutes of stimulation to both sides of the brain daily for five days. The other ten received a sham treatment that mimicked electrical stimulation. All 20 patients also participated in 60 minutes of occupational and physical therapy daily.
The investigators used magnetic resonance imaging (MRI) scans of the brain to “map” the brain lesions and their relationship to the motor cortex. “This novel approach strengthens the results,” noted Schlaug, “since no other between-group factor could explain the therapy’s effects.”
The threefold improvement seen in the brain stimulated patients included an improved ability to perform wrist and finger movements and to grasp. The MRIs also showed that the motor skill improvements correlated with increased activity in the non-damaged motor part of the stroke hemisphere.
This study demonstrates that stroke patients can achieve better improvement in motor skills when they receive brain stimulation to both hemispheres along with physical and occupational therapy. Schlaug noted that this work “is a testament of just how plastic the brain can be if novel and innovative therapies are applied using our current knowledge of brain function.”
Lindenberg R et al. Neurology 2010 November 10 online