EEG coherence in Alzheimer's disease

T. Locatelli, M. Cursi, D. Liberati, M. Franceschi, G. Comi

Research output: Contribution to journalArticle


EEG coherence can be used to evaluate the functionality of conical connections and to get information about the synchronization of the regional cortical activity. We studied EEG coherence in patients affected by clinically probable Alzheimer's disease (AD) in order to quantify the modifications in the cortico-cortical or cortico-subcortical connections. The EEGs were recorded in 10 AD patients (with mild or moderate degrees of dementia) and in 10 normal age- matched subjects, at rest and eye-closed, from 16 electrodes with linked-ears reference. Spectral parameters and coherence were calculated by a multichannel autoregressive model using 50 artifact-free epochs, 1 s duration each. Alpha coherence was significantly decreased in 6 patients, the decrease being more accentuated in the area near the electrode taken into account; a significant delta coherence increase was found in a few patients between frontal and posterior regions. The AD group showed a significant decrease of alpha band coherence, in particular in temporo-parieto-occipital areas, more evident in patients with a more severe cognitive impairment. These abnormalities could reflect two different pathophysiological changes: the alpha coherence decrease could be related to alterations in cortico-cortical connections, whereas the delta coherence increase could be related to the lack of influence of subcortical cholinergic structures on cortical electrical activity.

Original languageEnglish
Pages (from-to)229-237
Number of pages9
JournalElectroencephalography and Clinical Neurophysiology
Issue number3
Publication statusPublished - Mar 1998


  • Alzheimer's disease
  • Autoregressive model
  • Dementia
  • EEG coherence
  • Quantitative EEG

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

Fingerprint Dive into the research topics of 'EEG coherence in Alzheimer's disease'. Together they form a unique fingerprint.

  • Cite this