Introduction
Previous studies showed that slowing of electroencephalographic (EEG)
and magnetoencephalographic (MEG) waves assessed by power spectral
density (PSD) may be related to cognitive decline in Parkinson’s disease
(PD) patients.1–3 Multimodal studies evaluating
associations between PD-specific neuroimaging and neurophysiological
biomarkers in revealing executive dysfunction mechanisms in PD are
scarce, and especially in studying the association of resting state
brain waves (PSD-EEG) with the dopaminergic function imaging methods.
Currently, a gold standard diagnostic tool in PD is positron emission
computed tomography (PET/CT), particularly using the PD-specific
radiotracer, e.g., the [18F]Fluorodopa
([18F]FDOPA) uptake ratio in the striatum, which
reflects dopaminergic deficiency in idiopathic PD
patients.4–7 Multimodal studies with usage of the
PET/CT, EEG and behavioral testing may have scientific relevance in an
understanding of neural mechanisms in PD-related executive dysfunction,
but also they may be of great practical importance for PD diagnosis.
Hence, our study aimed to (i) compare the values of resting state
PSD-EEG, striatal [18F]FDOPA PET/CT uptake and
neuropsychological cognitive testing parameters between mild PD patients
and healthy controls, as well as (ii) to evaluate associations between
these outcomes. Additional aim was to estimate PD diagnostic accuracy
(with receiver operating characteristic [ROC] curves) of the PSD-EEG
parameters in reference to the gold diagnostic standard of the striatal
[18F]FDOPA PET/CT uptake ratio.
According to the “dual hypothesis”,8 assuming the
dopaminergic-mediated striatofrontal executive dysfunction in
early-stage PD, we hypothesized that values of (i) the PSD-EEG, striatal
[18F]FDOPA PET/CT uptake ratio and
neuropsychological parameters would differ between mild PD patients and
healthy controls and (ii) that the PD-specific neuroimaging findings
(increased PSD-EEG alpha- and theta- waves and decreased striatal
[18F]FDOPA PET/CT uptake ratio) would be
correlated to each other and with neuropsychological outcomes reflecting
executive dysfunction.