Slowing of EEG Background Activity in Parkinson’s and Alzheimer’s Disease with Early Cognitive Dysfunction

Abstract

Background: Slowing of the electroencephalogram (EEG) is frequent in Parkinson’s (PD) and Alzheimer’s disease (AD) and correlates with cognitive decline. As overlap pathology plays a role in the pathogenesis of dementia, it is likely that demented patients in PD show similar physiological alterations as in AD.Objective: To analyze distinctive quantitative EEG characteristics in early cognitive dysfunction in PD and AD.Methods: Forty patients (20 PD- and 20 AD patients with early cognitive impairment) and 20 normal controls (NC) were matched for gender, age, and education. Resting state EEG was recorded from 256 electrodes. Relative power spectra, median frequency (4–14 Hz), and neuropsychological outcome were compared between groups.Results: Relative theta power in left temporal region and median frequency separated the three groups significantly (p = 0.002 and p < 0.001). Relative theta power was increased and median frequency reduced in patients with both diseases compared to NC. Median frequency was higher in AD than in PD and classified groups significantly (p = 0.02).Conclusion: Increase of theta power in the left temporal region and a reduction of median frequency were associated with presence of AD or PD. PD patients are characterized by a pronounced slowing as compared to AD patients. Therefore, in both disorders EEG slowing might be a useful biomarker for beginning cognitive decline.

Placebo‐controlled crossover assessment of mecasermin for the treatment of Rett syndrome

“…Significant increases in frontal delta power with decreases in beta and gamma power suggest an increased contribution of slow‐wave activity following drug administration. These findings are consistent with reports of underlying cortical dysfunction related to various neurological disorders and encephalopathies, regardless of the underlying etiology 25, 33, 34. As these changes were seen in both main and secondary analyses, they represent relative strong findings.…”

Wavelet Energy and Wavelet Coherence as EEG Biomarkers for the Diagnosis of Parkinson’s Disease-Related Dementia and Alzheimer’s Disease

“…In these regions, the PD-D patients exhibited increased δ and θ power and decreased β power, which indicates slow EEG activity. When comparing AD patients, PD-D patients, PD patients without dementia, and controls, the highest δ and θ powers were observed in the PD-D patients and the lowest δ and θ powers were found in the controls (PD-D > AD > PD > CG) [22]. Similar patterns of highest δ energy and lowest α, β and γ energy in PD-D patients were observed in the current study.…”

Medial frontal ∼4-Hz activity in humans and rodents is attenuated in PD patients and in rodents with cortical dopamine depletion

“…In previous studies, it was found that temporal processing in PD appears to markedly affect beta and alpha rhythms in PD in motor cortex, although previous investigators did not focus on lower frequencies (Praamstra and Pope 2007). Recent work has implicated decreased theta in addition to alpha and beta frequencies in diagnosis of PD, in distinct brain regions (Benz et al 2014;Gu et al 2014Han et al 2013Praamstra and Pope 2007). Our work extends this line of research by focusing on MFC and linking spectral activity in PD patients with mechanistic theories (Cavanagh and Frank 2014) and single neuron activity that is consistently involved in temporal processing (Bekolay et al 2014;Kim et al 2013;Matell and Meck 2004;Narayanan and Laubach 2009;Niki and Watanabe 1979;Parker et al 2014;Xu et al 2014).…”