Characteristics of EEG during Various Meditations

EEG analysis was used to study about the brain condition during various meditations. Main subjects of this study were a male and a female practitioner who practiced meditation as their daily work. Comparisons were made with Zen priests, qigong masters, transcendental meditation (TM) practitioners and Japanese incense masters, whose EEGs have been previously measured by the authors. EEG was judged as being a capable indicator to estimate the brain condition during meditation: i.e. (1) relaxation degree was estimated by effective a amplitude on the occipital area; (2) variation of images, by changes in a frequency; (3) degree of the altered state of consciousness, by the ratio of the frontal/occipital a amplitude; (4) concen-tration degree, by the lag time of the a phase between the frontal and occipital areas; and (5) an activation rate of the verbal or imagery site, by the ratio of right/left occipital a amplitude.