Electroencephalographic functional connectivity is altered in persons with Down syndrome and Alzheimer's disease

Abstract

Background Persons with Down syndrome (DS) are at increased risk of developing Alzheimer's dementia (DS-AD). Due to heterogeneity in the functioning in persons with DS, it is difficult to use cognitive testing to assess whether a person with DS has developed dementia due to AD. Electroencephalography (EEG) functional connectivity has shown promising results as a diagnostic tool for AD in persons without DS. In the current exploratory study, we investigated whether EEG functional connectivity could be used as a diagnostic marker of AD in persons with DS and the association with symptoms. Methods Electroencephalography from 12 persons with DS and 16 persons with DS-AD were analysed, and both coherence and weighted phase lag index were calculated. In addition, we calculated the average coherence for fronto-parietal and temporo-parietal connections. Lastly, we investigated the correlation between the informant-based Dementia Screening Questionnaire in Intellectual Disability (DSQIID) and total alpha coherence. Results Decreased alpha and increased delta coherence and weighted phase lag index were observed in DS-AD as compared with DS. The decrease in alpha coherence was more marked in the fronto-parietal connections as compared with the temporo-parietal connections. No significant correlation was found between DSQIID and total alpha coherence (P value = 0.095, rho = À0.335). Conclusion The decreased alpha coherence and weighted phase lag index have previously been found in AD. The increased delta coherence and weighted phase lag index may indicate a different initial neurophysiological presentation as compared with patients with AD or may be a sign of more advanced disease. Larger studies are needed to confirm the current findings.

Type-2 diabetes alters hippocampal neural oscillations and disrupts synchrony between hippocampus and cortex

“…Coherence has been shown to be altered by neurological disorders such as stroke (Cassidy et al, 2020), depression (Danish M Khan et al, 2022;D. M. Khan, Yahya, Kamel, & Faye, 2023), AD (Rodinskaia, Radinski, & Labuhn, 2022) and Down syndrome with AD (Musaeus, Salem, Kjaer, & Waldemar, 2021). Similar to the PLI, we detected a decrease in coherence due to age or diabetes.…”

Type-2 Diabetes Alters Hippocampal Neural Oscillations and Disrupts Synchrony between the Hippocampus and Cortex

“…Unlike PLI which measures the consistency of the instantaneous phase difference between two signals, coherence determines the ratio of the cross spectral density and the individual auto spectral densities albeit with a lower temporal specificity. Coherence has been shown to be altered by neurological disorders such as stroke [52], depression [53,54], AD [55], Down syndrome with AD [56], and aging [57]. Similar to the PLI, we detected a decrease in coherence due to age or diabetes.…”

Bibliometric Analysis of Quantitative Electroencephalogram Research in Neuropsychiatric Disorders From 2000 to 2021

“…EEG functional connectivity has shown promising results as a diagnostic tool for AD. Similarly, in Down syndrome (DS) with Alzheimer's dementia, decreased alpha and increased delta coherence and weighted phase lag index were observed when compared to DS ( 125 ). EEG functional connectivity and complexity were used to predict depression severity among depressive patients.…”