DECREASED EEG MICROSTATE DURATION AND ANTERIORISATION OF THE BRAIN ELECTRICAL FIELDS IN MILD AND MODERATE DEMENTIA OF THE ALZHEIMER-TYPE

Spatially oriented segmentation allows researchers to break down the c ontinuous stream of the ongoing EEG into microstates with stable topog raphy of the brain electrical landscapes. The resulting microstates we re shown to be related to conscious mental experience as well as to ps ychiatric disorders typically associated with thought disorders. In th e present study, the microstates of the resting EEG of patients presen ting with mild or moderate probable dementia of the Alzheimer type (DA T) were investigated. A significant anteriorisation of the centers of gravity of the microstate fields, an increase of the microstates' opti mal window size and a reduced duration of sustained microstates were f ound. These differences were statistically more robust than the typica l changes in the frequency domain (diffuse slowing) and were significa ntly correlated with the cognitive decline. The adaptive spatial segme ntation into microstates is discussed as a method to extract meaningfu l EEG parameters for the early diagnosis and staging of Alzheimer's di sease. (C) 1997 Elsevier Science Ireland Ltd.