Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022;87(2):643-664.
doi: 10.3233/JAD-215421.

Exploring Network Properties Across Preclinical Stages of Alzheimer's Disease Using a Visual Short-Term Memory and Attention Task with High-Density Electroencephalography: A Brain-Connectome Neurophysiological Study

Ioulietta Lazarou  1   2 , Kostas Georgiadis  1   3 , Spiros Nikolopoulos  1 , Vangelis P Oikonomou  1 , Thanos G Stavropoulos  1 , Anthoula Tsolaki  1   4 , Ioannis Kompatsiaris  1 , Magda Tsolaki  1   2   4 ; RADAR-AD Consortium
Affiliations

Exploring Network Properties Across Preclinical Stages of Alzheimer's Disease Using a Visual Short-Term Memory and Attention Task with High-Density Electroencephalography: A Brain-Connectome Neurophysiological Study

Ioulietta Lazarou et al. J Alzheimers Dis. 2022.

Abstract

Background: Visual short-term memory (VSTMT) and visual attention (VAT) exhibit decline in the Alzheimer's disease (AD) continuum; however, network disruption in preclinical stages is scarcely explored.

Objective: To advance our knowledge about brain networks in AD and discover connectivity alterations during VSTMT and VAT.

Methods: Twelve participants with AD, 23 with mild cognitive impairment (MCI), 17 with subjective cognitive decline (SCD), and 21 healthy controls (HC) were examined using a neuropsychological battery at baseline and follow-up (three years). At baseline, the subjects were examined using high density electroencephalography while performing a VSTMT and VAT. For exploring network organization, we constructed weighted undirected networks and examined clustering coefficient, strength, and betweenness centrality from occipito-parietal regions.

Results: One-way ANOVA and pair-wise t-test comparisons showed statistically significant differences in HC compared to SCD (t (36) = 2.43, p = 0.026), MCI (t (42) = 2.34, p = 0.024), and AD group (t (31) = 3.58, p = 0.001) in Clustering Coefficient. Also with regards to Strength, higher values for HC compared to SCD (t (36) = 2.45, p = 0.019), MCI (t (42) = 2.41, p = 0.020), and AD group (t (31) = 3.58, p = 0.001) were found. Follow-up neuropsychological assessment revealed converge of 65% of the SCD group to MCI. Moreover, SCD who were converted to MCI showed significant lower values in all network metrics compared to the SCD that remained stable.

Conclusion: The present findings reveal that SCD exhibits network disorganization during visual encoding and retrieval with intermediate values between MCI and HC.

Keywords: Alzheimer’s disease; brain networks; electroencephalography; mild cognitive impairment; subjective cognitive decline; visual attention; visual short-term memory.

PubMed Disclaimer

Conflict of interest statement

Authors’ disclosures available online (https://www.j-alz.com/manuscript-disclosures/21-5421r1).

Figures

Fig. 1
Fig. 1
EEG, Eye-Tracker Set-Up, and VAT & VSTMT process timeline
Fig. 2
Fig. 2
Outline of the experimental procedure and the methodology for extracting the network metrics derived from Correlation Matrices after VAT and VMT.
Fig. 3
Fig. 3
Boxplots showing differences for the four groups of participants (HC = 21, SCD = 17, MCI = 23, AD = 12) in Clustering Coefficient, Strength, and Betweenness Centrality during VAT and VSTMT.
Fig. 4
Fig. 4
Topoplots for the three network metrics (clustering coefficient, strength and betweenness centrality during VAT (right) and VSTMT (left) across the four groups of participants (HC = 21, SCD = 17, MCI = 23, AD = 12).
Fig. 5
Fig. 5
ROC Curves showing the Clustering Coefficient, Strength, and Betweenness centrality at VAT and VSTMT for discriminating between: A) SCD and HC, B) MCI and HC, C) AD and HC, D) MCI and SCD, E) SCD and AD, F) MCI and AD.
See this image and copyright information in PMC

References

    1. (2021) 2021 Alzheimer’s disease facts and figures. Alzheimers Dement 17, 327–406. - PubMed
    1. Gauthier S, Reisberg B, Zaudig M, Petersen RC, Ritchie K, Broich K, Belleville S, Brodaty H, Bennett D, Chertkow H, Cummings JL, de Leon M, Feldman H, Ganguli M, Hampel H, Scheltens P, Tierney MC, Whitehouse P, Winblad B (2006) Mild cognitive impairment. Lancet 367, 1262–1270. - PubMed
    1. Mohs RC, Knopman D, Petersen RC, Ferris SH, Ernesto C, Grundman M, Sano M, Bieliauskas L, Geldmacher D, Clark C, Thal LJ (1997) Development of cognitive instruments for use in clinical trials of antidementia drugs: Additions to the Alzheimer’s disease assessment scale that broaden its scope. Alzheimer Dis Assoc Disord 11, S13–21. - PubMed
    1. Slot RER, Sikkes SAM, Berkhof J, Brodaty H, Buckley R, Cavedo E, Dardiotis E, Guillo-Benarous F, Hampel H, Kochan NA, Lista S, Luck T, Maruff P, Molinuevo JL, Kornhuber J, Reisberg B, Riedel-Heller SG, Risacher SL, Roehr S, Sachdev PS, Scarmeas N, Scheltens P, Shulman MB, Saykin AJ, Verfaillie SCJ, Visser PJ, Vos SJB, Wagner M, Wolfsgruber S, Jessen F, Boada M, de Deyn PP, Jones R, Frisoni G, Spiru L, Nobili F, Freund-Levi Y, Soininen H, Verhey F, Wallin ÅK, Touchon J, Rikkert MO, Rigaud AS, Bullock R, Tsolaki M, Vellas B, Wilcock G, Froelich L, Bakardjian H, Benali H, Bertin H, Bonheur J, Boukadida L, Boukerrou N, Chiesa P, Colliot O, Dubois B, Dubois M, Epelbaum S, Gagliardi G, Genthon R, Habert MO, Houot M, Kas A, Lamari F, Levy M, Metzinger C, Mochel F, Nyasse F, Poisson C, Potier MC, Revillon M, Santos A, Andrade KS, Sole M, Surtee M, Thiebaud de Schotten M, Vergallo A, Younsi N, van der Flier WM (2019) Subjective cognitive decline and rates of incident Alzheimer’s disease and non-Alzheimer’s disease dementia. Alzheimers Dement 15, 465–476. - PMC - PubMed
    1. Verfaillie SCJ, Binette AP, Vachon-Presseau É, Tabrizi S, Savard M, Bellec P, Ossenkoppele R, Scheltens P, van der Flier WM, Breitner JCS, Villeneuve S (2017) Subjective cognitive decline is associated with altered posterior cingulate connectivity in elderly with a familial history of Alzheimer’s disease. Alzheimers Dement 13, P33–P34.

Publication types