Serial quantitative EEG among elderly subjects with delirium.

Serial quantitative electroencephalographic (QEEG) studies were performed in 33 elderly delirious, demented, and control subjects to determine which QEEG variables were associated with changes in clinical state as measured by the Folstein Mini-mental State Examination (MMSE). Conventional EEGs and brain maps were independently rated by two electroencephalographers without knowledge of clinical diagnoses. Correlational analyses were performed using these ratings, along with numerical data from QEEG. In the delirium group (n = 15), changes in scores for the relative power map and changes in relative power in the alpha band had significant associations with changes in MMSE. In the dementia group (n = 10), changes in score for absolute power maps and changes in absolute power in the delta band had significant associations with changes in MMSE. In the control group, changes in MMSE over time were negligible. These findings have potential clinical utility in diagnosing delirium, and in providing a quantitative measure of its severity, which can be used serially.