Imagine looking at a wall clock and seeing only the right half of the face…or hearing only sounds that come from your right. Not seeing or responding to stimuli on the left side is a fact of life for about 50% of stroke patients due to a brain condition called hemispatial neglect (“hemineglect”). Only about half of hemineglect patients go on to recover without treatment, and recovery can take days to years, depending on the severity of the stroke. Now a recent study brings good news…it reveals that applying magnetic stimulation daily for just two weeks to certain areas of the brain may jump-start recovery and help stroke survivors see, hear and respond normally.
This technique, called continuous theta-burst stimulation or TBS, was developed about 15 years ago primarily to treat depression. But if future research confirms the new findings, it could soon be used to treat stroke victims, too. Researchers at the Santa Lucia Foundation in Rome performed the study, which was published in December 2011 in Neurology.
REBALANCING THE BRAIN
When a stroke affects the right side of the brain, it causes hyperactivity on the left side of the brain, and this is what leads to an inability to see, hear and/or respond to stimuli on the left. Hemineglect can technically occur on either side of the brain, but because of the brain’s anatomy, the sensory deficit most often occurs on the left.
The traditional treatment for hemineglect consists of mental rehab tasks, for example, matching objects on a computer screen, completing paper-and-pencil tasks to improve visual scanning (for example, the ability to find a friend in a crowded restaurant) and doing physical therapy exercises (such as repetitive movements of the arm or leg) to improve motor skills. Researchers wanted to investigate whether several weeks of TBS therapy would promote faster and longer-term recovery.
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A STIMULATING STUDY
Twenty patients who had had strokes causing hemineglect participated in the four-week study. Five days a week, all participants took part in standard mental and physical rehab sessions. For the first two weeks of the study, though, on weekday mornings, all patients had 15 minutes of either “real” or “sham” TBS sessions. Then, to measure whether participants had improvement in their ability to perceive stimuli that take place on their left sides, researchers gave participants the Behavioral Inattention Test (BIT), which covered such tasks as drawing, dialing a phone and reading a menu.
The results: Researchers found that test scores for those who received real TBS treatment improved by 16% immediately following the two weeks of therapy, revealing that perception and response to left-side stimuli had improved. After four weeks, TBS patients showed a 23% improvement in test scores, indicating that TBS benefits continued after treatment had ended—and grew. On the other hand, participants receiving sham TBS showed no clinically significant improvements in test scores after two or four weeks.
A TREATMENT OF THE FUTURE
To see what these findings might mean for my readers, I called Randolph S. Marshall, MD, chief of the stroke division at The Neurological Institute of New York at Columbia University Medical Center in New York City. He coauthored the accompanying editorial in the journal. Dr. Marshall told me that this study showed the longest-lasting effect of TBS thus far and that once patients with hemineglect start to improve, the improvement usually continues. No one knows exactly how TBS works in the brain, but Dr. Marshall said it seems to make neuron firing less frequent and thus calms the overexcitability in the brain.
Psychiatrists who administer TBS for depression conduct treatments in their offices and clinics, but for now, TBS for hemineglect is taking place only for research at some teaching hospitals, said Dr. Marshall. So you can’t even ask for it off-label right now, unfortunately. More research will help discover how to maximize the treatment’s effectiveness, figure out which patients are most likely to benefit from it and identify potential side effects—and it will help persuade insurance companies to cover the cost. (TBS sessions for depression run from about $200 to $300 each.) Dr. Marshall anticipates that within a few years, the country’s network of specialized stroke centers will have doctors trained and ready to put TBS therapy into practice.