EEG-based neurophysiological indicators of hallucinations in Alzheimer's disease: Comparison with dementia with Lewy bodies

Neurobiol Aging. 2018 Jul;67:75-83. doi: 10.1016/j.neurobiolaging.2018.03.013. Epub 2018 Mar 19.


We studied neurophysiological indicators of hallucinations in Alzheimer's disease patients with hallucinations (ADhall+), and compared them with nonhallucinating AD (ADhall-) and dementia with Lewy bodies (DLBhall+) patients. Thirty-six matched ADhall+ and 108 ADhall- and 29 DLBhall+ patients were selected from the Amsterdam Dementia Cohort. Electroencephalography (EEG) spectral and functional connectivity (FC) analyses (phase lag index) were performed. Quantitative and visual EEG measures were combined in a random forest algorithm to determine which EEG-based variable(s) play a role in hallucinations. ADhall+ patients showed lower peak frequency (7.26 vs. 7.94 Hz, p < 0.01), α2-and β-power, and α2-FC but higher δ-power compared to ADhall-. ADhall+ showed lower δ-power, higher β-power, and α1-FC than DLBhall+ but did not differ in peak frequency (7.26 vs. 6.95 Hz), θ- or α-power. ADhall+ patients could be differentiated from ADhall- and DLBhall+ with a weighted accuracy of 71% with α1-power and 100% with β-FC, the 2 most differentiating features. In sum, EEG slowing and decrease in α1-and β-band activity form potential neurophysiological indicators of underlying cholinergic deficiency in ADhall+ and DLBhall+.

Keywords: Alzheimer's disease; Dementia with Lewy bodies; EEG; Hallucinations; Random forest.

Publication types

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

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / psychology*
  • Cognition / physiology
  • Cohort Studies
  • Electroencephalography*
  • Female
  • Hallucinations / diagnosis*
  • Hallucinations / physiopathology*
  • Humans
  • Lewy Body Disease / psychology*
  • Male
  • Middle Aged