Resting-state EEG Findings in Differentiating Alzheimer’s Disease From Amnestic Mild Cognitive Impairment and Healthy Elderly Controls
Özgecan Kaya1
, Duygu Hünerli Gündüz2, Deniz Yerlikaya2, Görsev G. Yener3
1Sakarya University Training and Research Hospital, Clinic of Neurology, Sakarya, Turkey
2Dokuz Eylul University Institute of Health Sciences, Department of Neurosciences, Izmir, Turkey
3Izmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, Izmir, Turkey; Izmir University of Economics, Faculty of Medicine, Izmir, Turkey
Keywords: Alzheimer’s disease, mild cognitive impairment, resting-state EEG, delta, theta
Abstract
Objective: We aimed at investigating alterations in Resting-State electroencephalography (rsEEG) patterns of individuals with amnestic mild cognitive impairment (aMCI), and Alzheimer’s disease (AD).
Materials and Methods: Twenty healthy controls (HC) with 20 aMCI, and 20 AD patients were included in the study. EEG data was recorded for 4 minutes of eyes-closed condition according to the International 10-20 system. EEG rhythms of interest were delta (0.5-3.9 Hz), theta (4-7.8 Hz), alpha 1 (8-10.4 Hz), alpha 2 (10.5-13 Hz), and beta (13-30 Hz). The discriminatory power of rsEEG between groups was evaluated using the receiver operating characteristic analysis. Correlations among cognitive scores and power values of rsEEG were analyzed using Pearson correlation analysis.
Results: We observed effects on delta [F(2.57): 8.353; p=0.001], theta [F(2.57): 5.038; p=0.010], alpha 1 [F(2.57): 3.837; p=0.027], and alpha 2 [F(2.57): 4.209; p=0.020] power between groups. Moreover, interaction effects for anterior-posterior electrode location x group on delta [F(6.171): 2.621; p=0.038], and theta [F(6.171): 3.537; p=0.020] power were also detected. AD group demonstrated decreased delta power in frontal, central and parietal locations (for all; p<0.040) compared to HC and aMCI groups. In addition, the AD group also had decreased alpha and alpha1 power in comparison with HC (for all; p<0.026). Furthermore, we recorded a sensitivity of 80.0% and a specificity of 80.0% of delta power when using the cut-off score of >1.71 to identify AD from aMCI at central electrodes, and >1.73 to identify AD from HC at parietal electrodes. Moderate correlations were also detected among cognitive scores and rsEEG rhythms.
Conclusion: This study revealed the importance of delta and theta activity in rsEEG both as an electrophysiological indicator of cognitive status in AD and as a discriminatory tool for detecting aMCI.
Ethical approval for this study was obtained by the Dokuz Eylul University Non-interventional Research Ethics Committee (decision no: 2018/05-09, date: 15.02.2018).
Written informed consent was collected from all participants or their caregivers.
Externally peer-reviewed.
Concept: Ö.K., D.H.G., G.G.Y., Design: Ö.K., D.H.G., D.Y., G.G.Y., Data Collection or Processing: Ö.K., D.H.G., D.Y., Analysis or Interpretation: Ö.K., D.H.G., D.Y., Literature Search: Ö.K., D.H.G., Writing: Ö.K., D.H.G., D.Y., G.G.Y.
No conflict of interest was declared by the authors.
The research participants were analyzed retrospectively within the scope of the study supported by the project numbered 2013.KB.SAG.047 under the coordination of DEU-BAP.