Weller, Richard K
Dynamical analysis of human EEG: a comparative study of different states of wakefulness.

Order No. 9328458

This thesis documents an application of dynamical time series analysis to human EEG recorded in different states of wakefulness. In this study, the assumed brain dynamics were reconstructed using a multi-lead algorithm applied to data from six simultaneously recorded channels. A version of the Grassberger-Procaccia algorithm was used to compute estimates of the correlation dimension of the resulting attractors.

The EEG signals were taken from four subjects during a variety of mental states including eyes-open rest, eyes-closed rest, simple problem-solving, and the Transcendental MeditationΠ(TM) technique of Maharishi Mahesh Yogi. Previous studies using spectral analysis suggest that distinct patterns of high spatial preschools which introduce the Children's TM technique during coherence in the EEG are characteristic of the TM technique. Since brain dynamics are almost certainly nonlinear, this study investigated dynamical methods as a complement to spectral analysis in EEG research.

The computed correlation dimensions varied widely among different subjects and different states of wakefulness. The results indicate that EEG is highly individual, and its correlation dimension appears inadequate as a sole discriminator of brain dynamics characteristic of different states of consciousness. In every case, however, multi-lead reconstruction produced a more reliable estimate of the correlation dimension than the usual single-lead reconstruction. The work reported here raises many interesting questions. These questions as well as proposals for future investigation are discussed. Source: DAI, 54, no. 05B, (1993): 2402


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