Correlation between cortical theta activity and hippocampal volumes in health, mild cognitive impairment, and mild dementia

Cognitive decline is known to be associated with both increased B power ove r frontal regions and hippocampal atrophy. The aim of this study was to rev eal the relation between these parameters in groups with mild dementia, mil d cognitive impairment, and healthy control subjects. The authors examined a preliminary randomly selected sample of 39 right-handed subjects joining the Leipzig Longitudinal Study of the Aged, consisting of 17 normal elderly subjects, 12 patients with mild cognitive impairment, and 10 patients with mild dementia assessed by Clinical Dementia Rating. All subjects were betw een 75 and 85 years old (mean age, 78 years: standard deviation. 2.78 years ) and underwent EEG and brain MRI. Mean spectral power densities were calcu lated, and hippocampal body volume was measured. Significant negative linea r correlations between theta power over frontal regions and hippocampal vol umes were found. The results support the assumption about a relationship be tween hippocampal atrophy and theta power, and may be helpful for a better understanding of the course of Alzheimer's disease.