QUANTITATIVE ELECTROENCEPHALOGRAPHY AND REGIONAL CEREBRAL BLOOD-FLOW - DISCRIMINANT-ANALYSIS BETWEEN ALZHEIMERS PATIENTS AND HEALTHY CONTROLS

Forty-two patients with probable Alzheimer's disease (AD) and 18 elder ly healthy controls underwent quantitative EEG (qEEG) and regional cer ebral blood flow (rCBF; Xe-133 clearance) examinations. Correlations w ere sought between relative qEEG band powers and percent rCBF values i n a posterior temporoparietal region of interest in either hemisphere, Moreover, stepwise discriminant analysis was applied to study the acc uracy of the two techniques in differentiating AD from healthy ageing, rCBF and qEEG were correlated with one another, especially in the rig ht hemisphere (p values ranging from <0.001 to <0.01), Significant cor relations were found between Mini Mental State Examination (MMSE) and relative power of both the 2- to 6-Hz and the 6.5- to 12-Hz bands on e ither side (p < 0.001), and between MMSE and left rCBF (p < 0.005), wh ile the correlation with right rCBF was poorer (p < 0.02), The statist ical procedure identified the right values of both examinations for th e discriminant analysis. Sensitivity of qEEG and rCBF employed togethe r was 88% and specificity 89%: with a total accuracy of 88.3%. The unr ecognized patients (n = 5) were affected by mild AD (4 scoring 3 at th e Global Deterioration Scale and 1 scoring 4). qEEG alone showed an ac curacy of 77% in the whole group and of 69% in mild AD, and rCBF alone an accuracy of 75% in the whole group and of 71% in mild AD. It is co ncluded that qEEG and rCBF examinations employed together are accurate tools to differentiate AD from normal ageing, although a lower degree of accuracy is achieved in mildly demented patients.