Effects of betel chewing on electroencephalographic activity: spectral analysis and topographic mapping.

The effect of betel chewing on the electroencephalographic (EEG) activity of 52 betel users was studied by spectral analysis and topographic mapping before and during betel chewing. Betel chewing increased both alpha and beta activities but decreased theta activity. These effects were most prominent for beta rhythm. Topographic mapping revealed that altered spectral rhythms were restricted to the occipital areas for the alpha band but were more widespread for both theta and beta bands. The present data suggest that betel chewing causes EEG changes associated with a state of arousal and to a lesser degree a state of relaxation.