M. Trifonov, V. Rozhkov

4. Conclusions and Future Work

The results of this study allow us to make a preliminary conclusion that one-dimensional pdf’s of EEG relative

displace ments can be used for understanding of the real EEG dynamics in various functional states and different

subjects. To a first approximation, in each case the empirically derived pdf are fitted quite well by the single

hyper gamma distribution. It means that only two parameters (sample mean of EEG relative displacements and

coefficient of variation) may be taken into account. Both these parameters exhibit subject’s individuality. The

first one reveals age and state dependence while the second one stays rather stable for a given subject over long

period of time except sleep stages. It is interesting to note that age-related dependence of E[ΔY1] looks like as

age-related dependence of the total brain white matter volume given in [9]. In addition the non-linear age effect

on E[ΔY1] is consistent with the suggestion that during late childhood period there is a shift of topological or-

ganization of brain white matter toward a more randomized configuration [10].

In our future research we are going to analyze much more EEG records to investigate in details the age and

time-specific dependence of the parameters mentioned above. The next interesting aspect of our future work is

the improvement of the fitting quality of the empirically derived pdf of EEG relative displacements by using

distribution that consists of a mixture of hyper gamma distribution.

Acknowledgements

The authors would like to express their sincere thanks to Prof. M. N. Tsitseroshin, Dr. E. A. Panasevich, and Dr.

S. S. Bekshaev for providing EEG data.

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