Relationship between Posterior Resting‐State Electroencephalographic Alpha Rhythms and Cerebrospinal Fluid Biomarkers of Neuropathology in Patients with Alzheimer’s Disease Mild Cognitive Impairment

Abstract Background Patients with mild cognitive impairment due to Alzheimer’s disease (ADMCI) are characterized by abnormalities in resting‐state electroencephalographic (rsEEG) rhythms as measures of brain neural synchronization dysfunction (Babiloni et al., PMID: 33860614). Here, we tested the two following hypotheses that those rsEEG abnormalities: (i) may be higher in ADMCI patients than in patients with MCI not due to AD (noADMCI); and (ii) may be related to the AD diagnostic amyloid‐tau biomarkers derived from cerebrospinal fluid (CSF). Method Datasets in 70 ADMCI patients, 45 patients noADMCI, and 45 normal elderly (Healthy) participants originated from a Eurasian archive. The eyes‐closed rsEEG rhythms were investigated at individual delta, theta, and alpha frequency bands and fixed beta and gamma bands. The eLORETA freeware estimated rsEEG cortical sources. Result Statistical results showed: (i) compared with the Healthy group, the posterior alpha rsEEG source activities were more reduced in the ADMCI group than in the noADMCI group (p < 0.001; Figure 1); (ii) in the ADMCI group, a strong negative correlation between the CSF phospho‐tau levels and the occipital alpha rsEEG source activities was observed (r = 0.4, p < 0.001; Figure 2). Interestingly, in the ADMCI group, no correlation between the CSF and magnetic resonance imaging (MRI; neurodegeneration) variables was observed. Conclusion In ADMCI patients, the abnormalities of cortical neural synchronization mechanisms underpinning brain arousal and vigilance are related to the AD diagnostic phospho‐tau biomarkers and precede a similar relationship between AD amyloid‐tau and neurodegeneration biomarkers. Remarkably, the amyloid‐tau‐neurodegeneration (ATN) AD model may be enriched with those pathophysiological ‘P’ biomarkers as revealed by rsEEG rhythms.