Correlation between cognitive brain function and electrical brain activity in dementia of Alzheimer type

Abstract

Psychometric tests which assess cognitive brain function in dementia disorders are partly prone to artifacts, e.g., the experience of the investigator and the cooperation of the patient influences the results. An objective way to assess the degree of cognitive disturbance could be to measure neuronal activity represented by the electrical brain activity. The aim of the present study was to investigate how well cognitive function in dementia assessed by psychometric tests correlates with electrical brain activity (EEG). Multichannel EEG data was reduced into 3-D intracerebral equivalent dipole EEG generators allowing a more convenient statistical data management and valid physiological data interpretation. 35 patients suffering from dementia of Alzheimer type were investigated. An increase of dipole strength in the slow frequency bands, a more anterior equivalent dipole of alpha- and beta-activity, and a slowing of the EEG with increasing cognitive deterioration could be demonstrated. The results support the hypothesis that the amount of disturbance of cognitive function in dementia can be assessed by measuring the electrical activity of the brain.

Determinants of Quantitative Spectral Electroencephalography in Early Alzheimer’s Disease: Cognitive Function, Regional Cerebral Blood Flow, and Computed Tomography

“…General level of cognitive function, assessed in several previous studies with the MMSE, is most consistently related to alpha activity on EEG in AD patients [8,13,16,17,46], in agreement with our findings. However, also correlations between overall cognitive function and delta and theta activity were observed in our study and in previous reports [13][14][15][16].…”

“…However, also correlations between overall cognitive function and delta and theta activity were observed in our study and in previous reports [13][14][15][16]. Our analysis of EEG activity in relation to domains of neuropsychological function showed that EEG abnormalities not only reflect a parietal lobe syndrome, as previously suggested [47], but that these disturbances are also closely related to frontal lobe functions.…”

“…Previous studies have linked the degree of abnormalities in various EEG bands to measures of overall cognitive function [8,[13][14][15][16][17], or to more specific neuropsychological defects [18][19][20]. However, few studies investigated relations between EEG parameters and single photon emission computed tomography (SPECT) [21][22][23][24][25] or structural abnormalities on computed tomography (CT) [26][27][28].…”

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

“…Decreased EEG coherence and global field synchronization in α-band as well as frontal shift of generators of α-activity have been reported already in the MCI stage of AD supporting the hypothesis that AD develops as a neocortical disconnection syndrome [13,15,16,17]. Various EEG parameters were correlated in previous studies with measures of general cognition, neuropsychological test scores, clinical rating scales, regional cerebral blood flow and glucose metabolism as measured by SPECT and PET, respectively [13,18,19,20,21,22]. …”

Mild Cognitive Impairment in Old-Age Depression Is Associated with Increased EEG Slow-Wave Power

“…Absolute delta and theta power in patients suffering from Alzheimer's disease is negatively correlated with cognitive function [14,15]. Furthermore, a positive correlation between cognitive performance and beta activity has been shown in patients suffering from Alzheimer's disease [16] as well as in nondemented elderly subjects [17].…”