Using magnets to stimulate a particular
area of the brain can reduce auditory hallucinations experienced by patients
with schizophrenia, report US researchers.
About 50% to 70% of patients with schizophrenia report having auditory
hallucinations, often in the form of imaginary voices. Drugs offer little help,
and these hallucinations can cause distress, disability, and leave patients
unable to control their behavior.
Previous experiments have shown that a brain area called the temporoparietal
cortex (at the side of the brain) is activated during auditory hallucinations in
schizophrenic patients, while other experiments have shown that applying a
magnetic field to this area reduces the activation.
To see if magnetic stimulation could reduce auditory hallucinations in
patients with schizophrenia, researchers led by Dr. Ralph E. Hoffman at Yale
University in New Haven, Connecticut, studied 12 schizophrenic patients with
daily auditory hallucinations. The investigators applied a low-frequency
magnetic field to the left temporoparietal cortex of each patient for 4 minutes
the first day, which increased by 4 minutes each day to 16 minutes on day 4. For
comparison purposes, each patient also went through a "sham" stimulation, where
patients had similar treatment but did not receive a magnetic field. The sham
stimulation was separated by 2 to 3 days from the active stimulation.
The treatment was well tolerated, according to a report in the March 25th
issue of The Lancet, and there was significant improvement in the hallucination
severity after 12 and 16 minutes of active stimulation, but not in the sham
stimulation. The severity of hallucinations was reduced in all but one patient.
However, in the 8 patients classified as responders, the hallucinations returned
after a period ranging from 4 days to 2 months after the treatment.
Whether patients respond to treatment could depend on whether the patient
was also receiving anticonvulsant drugs, which seemed to reduce the effects of
the magnetic field, the authors note, or differences in the location of the
speech processing areas in the brain.
Hoffman's team is continuing their research. They are studying whether the
reduction in auditory hallucinations can be sustained over a longer term, and
whether the magnet therapy can help other symptoms of schizophrenia.
