Activating Brain Hemisphere Lifts Spirits of some Depressed Patients

Findings support McLean researcher's dual-brain theory

March 11, 2002

Public Affairs

Belmont, MA - A McLean Hospital psychiatrist has uncovered evidence to support a striking thesis-that illnesses, such as depression, are associated with one half of the brain and that one approach to treating depressed patients is to activate the healthier hemisphere.

"If you activate the healthier hemisphere, you may help the person," said Fredric Schiffer, MD, an associate attending psychiatrist at McLean Hospital.

Schiffer, working with researchers at other institutions, reports in the March Neuropsychiatry, Neuropsychology, and Behavioral Neurology that severely depressed patients whose spirits were lifted when receiving visual stimuli primarily to the left side of the brain also experienced significant improvements in mood when their left hemispheres were treated with a more powerful form of stimulation, involving electromagnetic fields.

Schiffer's latest report is part of a larger theory, he contends, that each half of the healthy human brain houses a separate emotional mind. In a healthy person, the two work in harmony but in people with illnesses, such as depression, one hemisphere may sabotage or dominate the other.

Schiffer first developed his theory several years ago, when he found that he could elicit positive emotional responses from depressed patients by restricting visual stimuli to one hemisphere. He did this by equipping patients with goggles that restrict visual stimuli to the right field of vision. Because signals from the right field of vision travel primarily to the opposite side of the brain, the goggles direct stimuli mostly to the left hemisphere. He also created goggles channeling stimuli to the right hemisphere.

Schiffer found that a slight majority of depressed patients felt better when visual stimuli were directed primarily to their left hemispheres, suggesting their right hemispheres were functioning abnormally. Wanting a stronger way to stimulate the presumably healthier left hemisphere, Schiffer approached Alvaro Pascual-Leone, MD, PhD, a researcher at Boston’s Beth Israel Deaconess Medical Center, who helped develop a method of stimulating the brain by using electromagnetic fields, called transcranial magnetic stimulation (TMS).

Intriguingly, Pascal-Leone had found that the method benefitted only about 50 percent of depressed patients. Suspecting that those patients were the ones whose healthy hemispheres were being stimulated—and that such patients could be identified in advance by the goggle method—Schiffer, Pascual-Leone and colleagues embarked on an experiment. Using the goggles, they channeled visual stimuli primarily to the left hemisphere of 37 depressed patients for 45 seconds and then to the right for the same amount of time. Twenty patients said they felt better when stimuli were directed to the left side of the brain, suggesting it was the healthy hemisphere. Fifteen felt worse, suggesting the right half of the brain was the healthier one. The patients then received a two-week course of TMS treatments to only the left hemisphere.

Depression levels were tested in the patients prior to wearing the goggles and also two weeks after the last of a series of TMS treatments using a standard measure. In this measure, the Hamilton Depression Rating Scale (HDRS), the higher the score, the higher the level of depression. The 20 patients who felt more improvement with left hemisphere visual stimulation had a 42-percent reduction in HDRS. Fifty-percent reduction is considered remission. In fact, 75 percent displayed at least a 20-percent reduction, which is considered a positive response. By contrast, the average reduction in HDRS for those in the second group was only 11 percent, which is below the failure mark.

The study makes two points. "On the one hand, it can be used to fortify current TMS procedures by predicting which individuals with depression will most benefit," said Schiffer. "In addition, it bolsters my dual-brain hypothesis."

Schiffer, who uses goggles with positive results in his clinical practice, is taking his approach a step further. He is using fMRI to study how the brain changes with goggle use. "To me this is very exciting and may point the way to a clearer understanding of the mind and psychological problems," he said.

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