title: Changes in absolute power values of EEG spectra in the follow-up of Alzheimer's disease.
abstract: We have studied the absolute and relative power and amplitude of EEG spectra (T6-02) of 24 patients with "probable" Alzheimer's disease at the early stage of the disease and 1 year later and also compared the values to those of normal elderly controls. A remarkable variability of the absolute values was evident both for the patients and for the controls. The AD patients had significantly higher absolute theta amplitude and power and the absolute beta values tended to decrease compared to controls. Absolute delta and alpha values did not differ from those of the controls. The relative delta, theta and alpha power and amplitude, and beta amplitude showed significant changes in AD patients, whereas the relative beta power was unchanged. In the follow-up of AD patients at 1 year, absolute alpha values decreased and delta values tended to increase. As to relative values, both the alpha and the delta significantly changed but the theta and the beta were unaltered. We conclude that both absolute and relative power and amplitude values should be considered in EEG studies of dementia patients. Absolute values are especially useful in follow-up.
authors.affiliation: Department of Neurology, University of Kuopio, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Soininen
authors.forename: J
authors.initials: J
authors.lastname: Partanen
authors.forename: A
authors.initials: A
authors.lastname: Pääkkönen
authors.forename: E
authors.initials: E
authors.lastname: Koivisto
authors.forename: P J
authors.initials: PJ
authors.lastname: Riekkinen
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000503:physiopathology*; D001143:Arousal / Q000502:physiology; D002540:Cerebral Cortex / Q000503:physiopathology*; D004569:Electroencephalography / Q000295:instrumentation; D005071:Evoked Potentials / Q000502:physiology; D005500:Follow-Up Studies; D005583:Fourier Analysis; D006801:Humans; D009483:Neuropsychological Tests; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation