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Lazarou I, Georgiadis K, Nikolopoulos S, Oikonomou VP, Stavropoulos TG, Tsolaki A, Kompatsiaris I, Tsolaki M. 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. J Alzheimers Dis 2022; 87:643-664. [DOI: 10.3233/jad-215421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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.
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Affiliation(s)
- Ioulietta Lazarou
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
- 1 Department of Neurology, G.H. “AHEPA”, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Makedonia, Greece
| | - Kostas Georgiadis
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
- Informatics Department, Aristotle University of Thessaloniki, Makedonia, Greece
| | - Spiros Nikolopoulos
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
| | - Vangelis P. Oikonomou
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
| | - Thanos G. Stavropoulos
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
| | - Anthoula Tsolaki
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
- Greek Association of Alzheimer’s Disease and Related Disorders, Thessaloniki, Makedonia, Greece
| | - Ioannis Kompatsiaris
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
| | - Magda Tsolaki
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), Thessaloniki, Makedonia, Greece
- 1 Department of Neurology, G.H. “AHEPA”, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Makedonia, Greece
- Greek Association of Alzheimer’s Disease and Related Disorders, Thessaloniki, Makedonia, Greece
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Age-induced differences in brain neural activation elicited by visual emotional stimuli: A high-density EEG study. Neuroscience 2017; 340:268-278. [PMID: 27810392 DOI: 10.1016/j.neuroscience.2016.10.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 10/24/2016] [Accepted: 10/24/2016] [Indexed: 11/22/2022]
Abstract
Identifying the brain sources of neural activation during processing of emotional information remains a very challenging task. In this work, we investigated the response to different emotional stimuli and the effect of age on the neuronal activation. Two negative emotion conditions, i.e., 'anger' and 'fear' faces were presented to 22 adult female participants (11 young and 11 elderly) while acquiring high-density electroencephalogram (EEG) data of 256 channels. Brain source localization was utilized to study the modulations in the early N170 event-related-potential component. The results revealed alterations in the amplitude of N170 and the localization of areas with maximum neural activation. Furthermore, age-induced differences are shown in the topographic maps and the neural activation for both emotional stimuli. Overall, aging appeared to affect the limbic area and its implication to emotional processing. These findings can serve as a step toward the understanding of the way the brain functions and evolves with age which is a significant element in the design of assistive environments.
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Papadaniil CD, Kosmidou VE, Tsolaki A, Tsolaki M, Kompatsiaris I(Y, Hadjileontiadis LJ. Cognitive MMN and P300 in mild cognitive impairment and Alzheimer's disease: A high density EEG-3D vector field tomography approach. Brain Res 2016; 1648:425-433. [DOI: 10.1016/j.brainres.2016.07.043] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 11/25/2022]
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