NON LINEAR TIME SERIES ANALYSIS OF THE EEG DURING SLEEP

I calculate the fractal dimension and the largest Lyapunov exponent for the human electroencephalogram (EEG) during sleep. For this purpose I assume that the EEG is generated by a deterministic nonlinear dynamical system. Slight differences among sorne sleep stages are found. The used method is thoroughly described and for completeness it includes how to find part of the Lyapunov exponents spectrum, Kolmogorov-Sinai entropy and Lyapunov dimension. I also discuss sorne results that apparently challenge the belief that the EEG is solely generated by a deterministic nonlinear dynamical system.