Meditation and human brain health

Meditation and EEG

Electroencephalograph (EEG) recordings of skilled meditators showed a significant rise in gamma wave activity in the 80 to 120 Hz range during meditation. There was also a rise in the range of 25 to 42 Hz. These meditators had 10 to 40 years of training in Buddhist-based mental training. EEG done on meditators who had received recent training demonstrated considerably less rise.

The experienced mediators also showed increased gamma activity while at rest and not meditating.

During meditation there is a modest increase in slow alpha or theta wave EEG activity.

Chang and Lo found different results.First they classify five patterns in meditation based on the normal four frequency ranges (delta <>13Hz). The five patterns they found were:

1) delta

2) delta + theta

3) theta + slow alpha

4) high-amplitude alpha

5) amplitude suppressed ("silent and almost flat")

They found pattern #5 unique and characterized by:

1) extremely low power (significant suppression of EEG amplitude)

2) corresponding temporal patterns with no particular EEG rhythm

3) no dominating peak in the spectral distribution

They had collected EEG patterns from more than 50 meditators over the prior five years. Five meditation EEG scenarios are then described. They further state that most meditation is dominated by alpha waves. They found delta and theta waves occurred occasionally, sometimes while people fell asleep and sometimes not. In particular they found the amplitude suppressed pattern correlated with "the feeling of blessings."