Resting-state EEG alpha/theta ratio related to neuropsychological test performance in Parkinson's Disease

Objective: To determine possible associations of hemispheric-regional alpha/theta ratio (alpha/theta) with neuropsychological test performance in Parkinson's Disease (PD) non-demented patients. Methods: 36 PD were matched to 36 Healthy Controls (HC). The alpha/theta in eight hemispheric regions was computed from the relative power spectral density of the resting-state quantitative electroencephalogram (qEEG). Correlations between alpha/theta and performance in several neuropsychological tests were conducted, significant findings were included in a moderation analysis. Results: The alpha/theta in all regions was lower in PD than in HC, with larger effect sizes in the posterior regions. Right parietal, and right and left occipital alpha/theta had significant positive correlations with performance in Judgement of Line Orientation Test (JLOT) in PD. Adjusted moderation analysis indicated that right, but not left, occipital alpha/theta influenced the JLOT performance related to PD. Conclusions: Reduction of the occipital alpha/theta, in particular on the right side, was associated with visuospatial performance impairment in PD. Significance: Visuospatial impairment in PD, which is highly correlated with the subsequent development of dementia, is reflected in alpha/theta in the right posterior regions. The right occipital alpha/theta may represent a useful qEEG marker for evaluating the presence of early signs of cognitive decline in PD and the subsequent risk of dementia. (C) 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Automated summary

The study found that the alpha/theta ratio was lower in all brain regions in Parkinson's Disease patients compared to healthy controls, with significant positive correlations between alpha/theta in the right occipital lobe and visuospatial performance in PD. This suggests that the alpha/theta ratio in the right occipital lobe may be an important marker for evaluating early signs of cognitive decline and dementia risk in PD.