Quantitative electroencephalogram analysis in dementia with Lewy bodies and Alzheimer's disease

Abstract

Clinicopathophysiological differences between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) remain obscure. Our goals were to determine whether characteristic findings of electroencephalogram (EEG) power and coherence in DLB and a differential pathophysiological mechanism of quantitative EEG existed between DLB and AD. The group consisted of 15 patients with AD or DLB and 12 age-matched controls. Original EEG signals were recorded from 14 scalp electrodes positioned according to the International 10-20 System, using digitally linked earlobes as a reference. Although EEG power spectral analysis showed increasing EEG power density in patients with DLB in the delta and theta bands, such a difference did not exist in patients with AD. Compared with AD, the delta and theta band intrahemispheric coherence values in the fronto-temporo-central regions were higher in DLB. In the beta band, AD was lower than DLB in almost all temporo-centro-parieto-occipital regions. Comparing the mean power value between patients with/without donepezil treatment, there was a significantly lower EEG power density in the delta and theta bands in DLB subjects taking donepezil than in subjects not taking donepezil, whereas there was no significant difference in AD patients. These results suggest that cholinergic dysfunction is stronger in DLB than AD.

Abnormalities of Cortical Neural Synchronization Mechanisms in Subjects with Mild Cognitive Impairment due to Alzheimer’s and Parkinson’s Diseases: An EEG Study

“…It has been shown a greater power in the posterior delta and theta rsEEG rhythms in groups of PDD patients when compared with those of ADD individuals [29,73]. This effect was also described as an occipital "pre-alpha" peak in the rsEEG power spectrum [20].…”

Diagnosis of Alzheimers Disease from EEG Signals: Where Are We Standing?

“…It is also of great importance to verify whether EEG helps to distinguish between AD and other dementias; in the last years, studies have investigated whether EEG alone allows to differentiate between AD, subjective memory complaints [116,173,175], psychiatric disorders [173], vascular dementia [173,176,177,178,179,180], fronto-temporal dementia [116,173,180], dementia with Lewy bodies [173,181,182], dementia with Parkinson's disease [182], and vascular dementia with Alzheimer's disease [60]. The preliminary results are generally promising, but surely, additional investigations will be required to explore the potential of EEG for differential diagnosis of dementia, and brain disorders at large.…”

Evaluation of spectral ratio measures from spontaneous MEG recordings in patients with Alzheimer's disease

“…EEG and MEG slowing have not only been observed in AD, but also in other forms of dementia as mild cognitive impairment [18,19,32], vascular dementia [25,27], dementia associated with Parkinson's disease [26,48], Lewy body dementia [26,28,49], major depression [50,51], Huntington's chorea and progressive supranuclear palsy [16,26]. Further investigation should be attempted in order to study differences in slowing for every disorder.…”