Slowing on quantitative spectral EEG is a marker for rate of subsequent cognitive and functional decline in early Alzheimer disease

The relation between quantitative spectral electroencephalogram (qEEG) parameters and subsequent rate of cognitive, functional, and behavioral decline in 82 consecutive patients with early probable Alzheimer disease (NINCDS-ADRDA criteria) was examined in a prospective study. The qEEG was performed at initial examination and global cognitive function, activities of daily living, and behavior were assessed at initial evaluation and after a period of 6 months. Using multiple linear regression analysis, higher frontocentral and parieto-occipital theta values, lower parieto-occipital beta values, and lower peak frequency were significantly associated with more decline in global cognitive function over the follow-up period. In addition, lower parieto-occipital beta values were significantly related to more decline in activities of daily living. These associations were independent of demographic (age, sex, and education) and disease characteristics [initial Cambridge Examination for Mental Disorders of the Elderly Cognitive test (CAMCOG) or Mini-Mental State Examination scores, estimated duration of symptoms, estimated prior rate of decline, and dementia severity]. In a separate multiple logistic regression analysis, prediction of rapidly progressive decline, defined as 8 or more points decline in CAMCOG scores (n = 21), could be made with parieto-occipital and frontocentral beta values. The results suggest that slowing on qEEG is a marker for subsequent rate of cognitive and functional decline in mildly demented AD patients, independent of demographic or disease characteristics.