Increased frontal phase-locking of event-related theta oscillations in Alzheimer patients treated with cholinesterase inhibitors

Yener G. G., Guntekin B., Oniz A., Basar E.

INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY, vol.64, no.1, pp.46-52, 2007 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 64 Issue: 1
  • Publication Date: 2007
  • Doi Number: 10.1016/j.ijpsycho.2006.07.006
  • Journal Name: INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Social Sciences Citation Index (SSCI), Scopus
  • Page Numbers: pp.46-52
  • Keywords: Alzheimer, dementia, oscillations, ERP, theta, P300, phase-locking, cholinergic, BRAIN FUNCTIONAL CONNECTIVITY, WORKING-MEMORY TASK, CEREBRAL-BLOOD-FLOW, VISUAL-CORTEX, CHOLINERGIC MODULATION, ALPHA-OSCILLATION, SHORT-TERM, DISEASE, ACETYLCHOLINE, EEG
  • Dokuz Eylül University Affiliated: No

Abstract

This is a pilot study describing event-related oscillations in patients with Alzheimer-type dementia (AD). Theta responses of 22 mild probable AD subjects according to NINCDS-ADRDA criteria (11 non-treated, 11 treated by cholinesterase inhibitors), and 20 healthy elderly controls were analyzed by using the conventional visual oddball paradigm. We aimed to compare theta responses of the three groups in a range between 4-7 Hz at the frontal electrodes. At F-3 location, theta responses of healthy subjects were phase locked to stimulation and theta oscillatory responses of non-treated Alzheimer patients showed weaker phase-locking, i.e. average of Z-transformed means of correlation coefficients between single trials was closer to zero. In treated AD patients, phase-locking following target stimulation was two times higher in comparison to the responses of non-treated patients. The results indicate that the phase-locking of theta oscillations at F-3 in the treated patients is as strong as the control subjects. The F-4 theta responses were not statistically significant between the groups. Our findings imply that the theta responses at F3 location are highly unstable in comparison to F4 in non-treated mild AD patients and cholinergic agents may modulate event-related theta oscillatory activities in the frontal regions. (c) 2006 Elsevier B.V. All rights reserved.