Frontal White Matter Volume and Delta EEG Sources Negatively Correlate in Awake Subjects With Mild Cognitive Impairment and Alzheimer's Disease

Clin Neurophysiol. 2006 May;117(5):1113-29. doi: 10.1016/j.clinph.2006.01.020. Epub 2006 Mar 27.


Objective: A relationship between brain atrophy and delta rhythmicity (1.5-4 Hz) has been previously explored in Alzheimer's disease (AD) subjects [Fernandez A, Arrazola J, Maestu F, Amo C, Gil-Gregorio P, Wienbruch C, Ortiz T. Correlations of hippocampal atrophy and focal low-frequency magnetic activity in Alzheimer disease: volumetric MR imaging-magnetoencephalographic study. Am J Neuroradiol. 2003 24(3):481-487]. In this study, we tested the hypothesis that such a relationship does exist not only in AD patients but also across the continuum of subjects with mild cognitive impairment (MCI) and AD.

Methods: Resting, eyes-closed EEG data were recorded in 34 MCI and 65 AD subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. Cortical EEG sources were correlated with MR-based measurements of lobar brain volume (white and gray matter).

Results: A negative correlation was observed between the frontal white matter and the amplitude of frontal delta sources (2-4 Hz) across MCI and AD subjects.

Conclusions: These results confirmed for the first time the hypothesis that the sources of resting delta rhythms (2-4 Hz) are correlated with lobar brain volume across MCI and AD subjects.

Significance: The present findings support, at least at group level, the 'transition hypothesis' of brain structural and functional continuity between MCI and AD.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alzheimer Disease / complications
  • Alzheimer Disease / pathology*
  • Alzheimer Disease / physiopathology*
  • Brain Mapping
  • Case-Control Studies
  • Cognition Disorders / complications
  • Cognition Disorders / pathology*
  • Cognition Disorders / physiopathology*
  • Delta Rhythm*
  • Electroencephalography
  • Female
  • Frontal Lobe / pathology*
  • Frontal Lobe / physiopathology
  • Humans
  • Male
  • Mental Status Schedule
  • Neuropsychological Tests / statistics & numerical data
  • Spectrum Analysis
  • Wakefulness / physiology