The paper discusses the change rules of the complexity of EEG in different leads sites of the brain in meditation with the complexity analysis method in nonlinear kinetics to explore the brain functional change, and to find a new method of nonlinear science in study of EEG in the qigong state.

Experimental methods
58 healthy university students were divided into two groups: qigong group : 38 (male: 18, female: 20) control group : (20 male: 11, female: 9)
The qigong group did meditation for 20 min. and the control group did simulate meditation for 20 min. EEG was measured 10 min. before and after meditation and simulate meditation. The measurement took 2 sec. 2-4 OH2 EEG complex was analyzed according to the definition of complexity by Lempel and Ziv and the algorithms of Kaspar and Schuater.

Result
1. Influence of meditation on EEG

C(n) change of EEG complexity in meditation
(X bar ± SD, n=38)

electrode
position before in after
F3 0.157±0.016 0.146±0.015 0.157±0.023
F4 0.160±0.018 0.150±0.017 0.155±0.019
C3 0.158±0.019 0.149±0.010 0.158±0.024
C4 0.158±0.018 0.149±0.015 0.158±0.017
T3 0.172±0.023 0.163±0.018 0.172±0.027
T4 0.172±0.025 0.163±0.021 0.173±0.027
O1 0.159±0.023 0.158±0.022 0.158±0.023
O2 0.157±0.022 0.155±0.022 0.151±0.021

C(n) change of EEG complexity in simulate meditation (X bar±SD, n=20)

electrode
position before in after
F3 0.154±0.029 0.167±0.043 0.153±0.034
F4 0.155±0.040 0.152±0.044 0.153±0.032
C3 0.155±0.030 0.158±0.045 0.157±0.033
C4 0.158±0.032 0.153±0.037 0.171±0.036
T3 0.184±0.045 0.181±0.060 0.189±0.047
T4 0.173±0.041 0.173±0.051 0.196±0.048
O1 0.188±0.034 0.193±0.056 0.180±0.046
O2 0.174±0.029 0.176±0.055 0.167±0.040

Discussion:
From above we found that there was significant difference between EEG time order. During meditation, the complexity measure decreased and the control group did not show this tendency. It suggests that EEG developed from comparatively random disorder to a synchronization harmonious order in meditation.

THE COMPLEXITY OF EEG IN MEDITATION