REGIONAL CORRELATIONS BETWEEN THE EEG AND OXYGEN-METABOLISM IN DEMENTIA OF ALZHEIMERS TYPE

To determine the relationship between EEG slowing and cerebral hypomet abolism in dementia, 10 patients with dementia of Alzheimer's type (DA T) were evaluated with quantitative topographic EEG and positron emiss ion tomography (PET). Power in each 1 Hz frequency band from 2-20 Hz, power ratio index, and normalised PET data from corresponding cortical sites were compared to data obtained from 20 normal volunteers. PET r evealed significant parieto-temporal hypometabolism, and topographic E EG mapping and power spectrum analysis revealed a slowing of the backg round EEG that was most pronounced in the parietal-temporal areas. Cor relation analysis between EEG power spectrum data and CMRO2 revealed s ignificant negative correlations for frequencies below 8 Hz and signif icant positive correlations above 8 Hz in the parieto-temporal regions , which have previously been identified as the areas most severely aff ected by pathological changes associated with DAT. Correlation coeffic ients plotted as functions of frequency illustrated the relationships between EEG changes and reduced CMRO2, supporting previous views that EEG slowing in DAT may be related to hypometabolism in cortical region s most affected by the disease. (C) 1997 Elsevier Science Ireland Ltd.