Possible Treatment for Insomnia

Insomniacs who were subjected to mild frontal cerebral hypothermia showed reduced brain metabolism in the frontal cortex and reported an overall better and more refreshing sleep.

Researchers at the University of Pittsburgh (PITT; PA, USA) screened 148 subjects and identified 12 that met diagnostic and statistical manual of mental disorders (DSM-IV) criteria for primary insomnia. Eight of these completed the study. The patients used a medical device that overlay the frontal cortex on the scalp and delivered either a neutral temperature (control) or a mild hypothermic effect for 60 minutes; the subjects served as their own controls. The treatment was applied before bedtime and during the first cycle of non-rapid eye movement (NREM) sleep. The researchers analyzed core body temperature and NREM sleep using 18F-fluorodeoxyglucose positron-emission-tomography (PET) scanning.

The researchers found that the hypothermic treatment led to reduced metabolism in the underlying frontal and cingulate cortex. Five of eight patients experienced reduction in whole brain metabolism with the treatment. Treatment also led to an accelerated reduction in core body temperature at sleep onset. Of the patients, 75% reported sleep-related improvements, including a decrease in distracting thoughts, improved sleep maintenance, and more refreshing sleep. The findings were presented at the annual meeting of the associated professional sleep societies (SLEEP 2009), held during June 2009 in Seattle (WA, USA).

"It moves [insomnia] patients into a deeper sleep,” said lead author and study presenter Eric Nofzinger, M.D., a professor of psychiatry at PITT, who explained that the new approach is designed to counter the metabolic changes seen in brain images. "We're trying to push that back to the normal condition by applying surface cooling.”

Earlier brain-imaging studies have shown a reduction in metabolism in the frontal cortex in healthy individuals as they fell asleep. Insomniacs, however, experienced an increased metabolism compared with healthy volunteers, both before going to sleep and during NREM sleep. Other evidence suggests that people with insomnia have a generally higher metabolism, including faster heartbeats and hyper-arousal.

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