Intraindividual specificity and stability of human EEG: Comparing a linear vs a nonlinear approach
We have applied the so-called "unfolding dimension approach" to reanalyze an earlier longitudinal EEG study. Both linear and nonlinear approaches show that the EEG comprises a static, person-specific part upon which nonstatic and state-specific parts are superimposed. The intraindividual specificity and stability of the genetic part are similar between methods. This is assessed by comparing the outcome of a person to his own outcomes at later times (14 days and 5 years later), The nonlinear method revealed a median correlation coefficient rho = 0.55, whereas advanced linear methods showed a median rho = 0.84. An apparent effect for the 5-year interval was detected with the nonlinear method and is discussed in terms of the different assumptions of the two approaches concerning EEG signal generation.
dimension analysis similarity approach eeg stability power spectrum