Transcranial magnetic stimulation to curtail auditory hallucinations in schizophrenia
Mar 12, 2006 - 3:52:37 AM
Yale School of Medicine researchers are recruiting patients nationally for a clinical trial using transcranial magnetic stimulation (TMS) to help still the voices that are so troubling to some persons with schizophrenia.
"These hallucinations, which consist of spoken speech that are labeled 'voices' by patients themselves, are often very disabling and resistant to currently available medication therapies," said Ralph Hoffman, M.D., a professor in the Department of Psychiatry and principal investigator of the study.
Hoffman has received a $2.1 million, five-year grant from the National Institute of Mental Health to expand the research to include 90 patients. There are funds to fly patients to New Haven, where they will stay on a research unit during the five-to-eight week period that they are in the clinical trial. TMS generally is painless and is experienced as a knocking sensation. It is administered while persons are awake by positioning an electromagnetic coil on the scalp.
"It appears that stimulating populations of neurons once per second with TMS over many minutes modestly reduces the capacity of these neurons to activate each other," Hoffman said. "As a result, neural populations as a whole become less reactive or excitable. Our study findings suggest that hallucinations can be curtailed using this approach without interfering with normal brain function."
Hoffman recently completed a study testing TMS in different areas of the brain and found that positioning the TMS over what is known as Wernicke's region in the left temporal lobe, and a second region located on the opposite side of the brain, were optimal in reducing these hallucinations. He said these two brain areas, which ordinarily play key roles in perceiving words spoken by other persons, have also been found in other studies to be important in producing hallucinated "voices."
For patients enrolled in the trial, TMS will be administered to these brain areas once per second for 16 minutes daily over a three-week period. One-third of the subjects in the trial will start out receiving a placebo form of TMS. After three weeks, these subjects will also be offered a trial of real TMS. The study will use a magnetic resonance imaging brain scan to precisely position TMS over desired brain regions.
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