Source: Clin Cancer Res  |  Posted 9 years ago

Quantitative electroencephalogram is sensitive to the effects of psychostimulants in people's brains, and pharmaco-EEG studies should exclude such environmental factors as caffeine, suggest researchers at the Technical University, Dresden, Germany.

Despite its widespread use as a central nervous stimulant, caffeine's central pharmacodynamic properties have not been conclusively evaluated in humans.

Martin Siepmann and Wilhelm Kirch from the Medical Faculty's Institute of Clinical Pharmacology sought to assess the acute effects of the stimulant on measures of topographical quantitative electroencephalogram in normal subjects.

Ten healthy young men volunteered to receive placebo and 200 mg of caffeine as powder with water solution, which was equal to two cups of coffee.

The placebo and "coffee" beverages were administered under randomised, double-blind crossover conditions on two different occasions.

Both before and after the subjects received the drinks, a 17-channel quantitative EEG was recorded with participants' eyes open for 15 minutes and then closed for the same period of time.

When the subjects kept their eyes open, caffeine caused a significant reduction of total EEG power at fronto-parieto-occipital and central electrode positions of both hemispheres.

Absolute power of the slow and fast alpha and slow beta activities was diminished in various regions of the brain.

The effect was more pronounced when subjects were keeping their eyes open than with their eyes closed.