Researchers at Shepherd Center, Atlanta, USA, are studying whether stimulating the brain before rehabilitation could yield greater gains in motor function for people recovering from stroke. Researchers believe that the new approach could change common practices of care for certain stroke patients.
Shepherd Center is one of 12 US centres participating in a clinical trial that is evaluating whether coupling navigated transcranial magnetic stimulation (TMS) of the brain with standard occupational therapy can measurably improve hand and arm function following a stroke. Experts say this approach could unlock a totally new, non-invasive treatment to promote recovery and function.
“It’s really a seminal study in neurorehabilitation that, if successful, will change common practices for how we take care of certain stroke patients,” says Ford Vox, a physical medicine and rehabilitation physician at Shepherd Center and primary investigator for this study. “We have this golden opportunity right after someone has a stroke when we know people are most likely to improve or recover function, and this therapy may offer patients the best potential.”
Shepherd Center is testing a navigated brain stimulation system developed by a Finnish medical technology company called Nexstim. It uses transcranial magnetic stimulation therapy to apply a mild electromagnetic current to excite the brain, a technique that can be used to both investigate the brain’s functions and change them. The technique is growing in popularity as a way to map the brain before surgery and as a treatment for depression. Nexstim’s device provides visual guidance to the operator, who uploads and correlates MRI pictures of the patient’s brain with the device’s infrared guidance system. Then, the device creates a 3-D model of the patient’s brain, pinpointing the target site for stimulation in real time (called stereotactic guidance).
In this new trial, clinicians believe transcranial magnetic stimulation works by slowing activity in the healthy area of the brain, which can become overly active following a stroke, causing detriment to the injured side.
“By reducing brain activity on the side of the brain that was not injured, the injured side may actually have a better chance of recovery,” Vox explains.
The technology is akin to a more advanced version of constraint-induced therapy in which clinicians physically tie down a patient’s good arm, which forces the patient to use the injured side. With Nexstim’s non-invasive device, researchers are using electromagnetism to slow activity in portions of the healthy brain hemisphere that control the uninjured arm, similarly forcing the brain to use its injured half.
“People who have experienced a stroke often have limited resources and rehabilitation benefits,” Vox notes. “If initial results are confirmed, patients might be able to get that much more out of the limited time they have with therapists by using this technology.”
Eligible clinical trial participants receive either the navigated brain stimulation or a sham (simulated) treatment in conjunction with six weeks of hand and arm therapy provided by an occupational therapist. Researchers and study participants do not know whether they are in the treatment or simulation group. Visits start with 20 minutes of standardised, task-oriented activity followed by the treatment or simulated therapy and then an hour of upper-limb rehabilitation therapy.
The goal is to improve a patient’s range of motion, coordination, flexibility, strength, and use of the weak arm and hand. Specifically, researchers are interested to see whether – at the end of the study – patients are better able to perform daily activities, such as dressing, grooming, cooking, doing laundry, writing, typing and leisure activities. For example, is a patient now able to button a shirt that he couldn’t before, open a jar or screw-top bottle, pour beverages, manipulate keys to lock and unlock doors, use a phone or fold laundry?
In a similarly designed pilot study of the device conducted at the Rehabilitation Institute of Chicago, researchers found striking improvements in motor function among people receiving the targeted stimulation compared with those in the simulation group. At six months post-stroke, these patients were 30% more likely to have meaningful arm recovery (80% compared with just 50%). Researchers presented their findings in February 2014 at the American Heart Association and the American Stroke Association’s International Stroke Conference.
