EEG Abnormalities Are Associated with Different Cognitive Profiles in Alzheimer’s Disease

Abstract

Objective: Our purpose was to investigate associations between different cognitive profiles and their underlying functional brain changes as measured by electroencephalogram (EEG) in Alzheimer’s disease (AD). Methods: EEG was obtained and neuropsychological performance assessed in 254 patients with AD. The EEGs were visually assessed for the presence of focal and/or diffuse abnormalities. Multivariate analysis of variance for repeated measures was performed with presence of focal and/or diffuse abnormalities as between-subjects factor and neuropsychological tests as within-subject factor. Age, sex and education were entered as covariates. Results: Twenty-eight percent of the patients had a normal EEG, 32% had focal abnormalities, 14% diffuse abnormalities and 26% had both focal and diffuse abnormalities. Patients with a normal EEG presented with a cognitive profile in which memory was mostly impaired. Patients with focal and diffuse EEG abnormalities presented with a nonmemory profile. Conclusion: These results illustrate that specific types of EEG abnormalities are associated with different cognitive profiles in AD, providing biological support in terms of brain functioning for variability in cognitive impairment.

Association between EEG Abnormalities and CSF Biomarkers in a Memory Clinic Cohort

“…Occurrence of normal EEGs in some AD patients is in accordance with previous studies [8,35,40,41]. Smits et al [40] reported recently that visually assessed EEG abnormalities are associated with different cognitive profiles in AD. In their study 28% of AD patients had normal EEGs and a cognitive profile in which memory was mostly impaired.…”

“…It is known that the main risk factors for AD and MCI have also been reported as risk factors for cardiovascular disease and could modify the clinical expression of parallel neurodegenerative processes in the brain [38,39]. Occurrence of normal EEGs in some AD patients is in accordance with previous studies [8,35,40,41]. Smits et al [40] reported recently that visually assessed EEG abnormalities are associated with different cognitive profiles in AD.…”

Relationship Between EEG Beta Power Abnormality and Early Diagnosis of Cognitive Impairment Post Cerebral Hemorrhage

“…By employing this algorithm, 67 of the 69 CHNC patients were categorized as members of subgroup 1 (interval I), and 110 of the 113 CHCI patients were categorized as subgroup 2 (interval II). The classification used the 8 EEG channels (1,8,9,10,11,12,13, and 16) exhibiting the largest differences in relative beta power. We noted that beta power of patients on the highest channels (1, 10, and 12) displaying the 3-dimensional graph showed the difference directly.…”

“…Only 4 channels, 2(F3-C3), 4(P3-O1), 7(C4-P4), and 14(F8-T4), did not differ between CHCI and NC in relative beta power. Eight channels (1,8,9,10,11,12,13, and 16) exhibited the largest differences in relative beta power. Beta bandwidth signals of the above 8 EEG channels were selected for patients with post cerebral hemorrhage.…”

“…For example, signs of diffuse EEG slowing are useful in differentiating healthy humans from patients with Alzheimer disease (AD). 9 Smits et al 10 showed that specific types of EEG abnormalities are associated with different cognitive profiles in AD. Therefore, EEG may provide biological support in terms of brain functioning for variability in cognitive impairment.…”