Entropy changes in brain function.
The traditional way of analyzing brain electrical activity, on the basis of electroencephalography (EEG) records, relies mainly on visual inspection and years of training. Although it is quite useful, of course, one has to acknowledge its subjective nature that hardly allows for a systematic protocol. In the present work quantifiers based on information theory and wavelet transform are reviewed. The "relative wavelet energy" provides information about the relative energy associated with different frequency bands present in the EEG and their corresponding degree of importance. The "normalized total wavelet entropy" carries information about the degree of order-disorder associated with a multi-frequency signal response. Their application in the analysis and quantification of short duration EEG signals (event-related potentials) and epileptic EEG records are summarized.
Rosso
Osvaldo A
OA
Chaos and Biology Group, Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, 1428 Ciudad de Buenos Aires, Argentina. oarosso@fibetel.com.ar
D000161:Acoustic Stimulation; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000502:physiology*; D002648:Child; D003627:Data Interpretation, Statistical; D004569:Electroencephalography / Q000706:statistics & numerical data*; D019277:Entropy; D004827:Epilepsy / Q000503:physiopathology; D004832:Epilepsy, Absence / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology; D006801:Humans