Related Experiment Video
Updated: Jul 11, 2025
Application of Granger Causality Analysis of the Directed Functional Connection in Alzheimer's Disease and Mild Cognitive Impairment
Published on: August 7, 2017
Functional connectivity changes in mild cognitive impairment: A meta-analysis of M/EEG studies
Giulia Buzi1, Chiara Fornari2, Alessio Perinelli3
1U1077 INSERM-EPHE-UNICAEN, Caen 14000, France.
Objective:
Early synchrony alterations have been observed through electrophysiological techniques in Mild Cognitive Impairment (MCI), which is considered the intermediate phase between healthy aging (HC) and Alzheimer's disease (AD). However, the documented direction (hyper/hypo-synchronization), regions and frequency bands affected are inconsistent. This meta-analysis intended to elucidate existing evidence linked to potential neurophysiological biomarkers of AD.
Methods:
We conducted a random-effects meta-analysis that entailed the unbiased inclusion of Non-statistically Significant Unreported Effect Sizes ("MetaNSUE") of electroencephalogram (EEG) and magnetoencephalogram (MEG) studies investigating functional connectivity changes at rest along the healthy-pathological aging continuum, searched through PubMed, Scopus, Web of Science and PsycINFO databases until June 2023.
Results:
Of the 3852 articles extracted, we analyzed 12 papers, and we found an alpha synchrony decrease in MCI compared to HC, specifically between temporal-parietal (d = -0.26) and frontal-parietal areas (d = -0.25).
Conclusions:
Alterations of alpha synchrony are present even at MCI stage.
Significance:
Synchrony measures may be promising for the detection of the first hallmarks of connectivity alterations, even at the prodromal stages of the AD, before clinical symptoms occur.
Insights
Early brain synchrony changes, specifically decreased alpha synchrony in Mild Cognitive Impairment (MCI), may serve as biomarkers for Alzheimer's disease (AD) detection before symptoms appear.
Area of Science:
- Neuroscience
- Cognitive Science
- Biomarkers
Background:
- Mild Cognitive Impairment (MCI) represents a transitional stage between healthy aging (HC) and Alzheimer's disease (AD).
- Electrophysiological studies indicate early synchrony alterations in MCI, but findings on affected regions and frequency bands are inconsistent.
- Identifying reliable neurophysiological biomarkers for early AD detection is crucial.
Conclusions:
- Alpha synchrony alterations are detectable even in the Mild Cognitive Impairment (MCI) stage.
- Synchrony measures show promise for detecting early connectivity changes indicative of prodromal Alzheimer's disease (AD), preceding clinical symptom onset.
More Related Videos
09:01A Method for Investigating Age-related Differences in the Functional Connectivity of Cognitive Control Networks Associated with Dimensional Change Card Sort Performance
Published on: May 7, 2014
08:23A Multimodal Imaging- and Stimulation-based Method of Evaluating Connectivity-related Brain Excitability in Patients with Epilepsy
Published on: November 13, 2016