Recent research has found long-range electroencephalogram (EEG) power law correlations, indicating time scale invariance. However, the EEG is also rather noisy, displaying short-term decorrelation like white noise - i.e., what is scale invariant at one time period may disappear in the next. The paradoxical combination of short-range divergence, but long-range correlations, suggests that any long-range correlations detected in one sample may be spurious, since they could be related to amplitude fluctuations. To overcome this problem, this paper suggests a new technique for analysing EEG signals segmented by zero-crossings, using detrended fluctuation analysis (DFA), evaluated across two time periods (TIME) and different sites (SITE). A mean scaling exponent across all subjects and sites of α=0.67 was observed. MANOVA analysis indicates no significant main effect for TIME or interaction with SITE, suggesting that the zero-crossing method may be successful in determining the fractal nature of EEG dynamics across relatively long time scales. © 2003 Elsevier B.V. All rights reserved.

Item Type:	Refereed Article
Research Division:	Psychology and Cognitive Sciences
Research Group:	Psychology
Research Field:	Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology)
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in Psychology and Cognitive Sciences
Author:	Martin, F (Associate Professor Frances Martin)
ID Code:	29284
Year Published:	2004
Web of Science® Times Cited:	15
Deposited By:	Psychology
Deposited On:	2004-08-01
Last Modified:	2005-04-27
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