Brain 18F-DOPA PET and cognition in de novo Parkinson’s disease
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The role of mesocortical dopaminergic pathways in the cognitive function of patients with early Parkinson’s disease (PD) needs to be further clarified.
The study groups comprised 15 drug-naive patients with de novo PD and 10 patients with essential tremor (controls) who underwent 18F-DOPA PET (static acquisition, normalization on mean cerebellar counts) and an extended neuropsychological test battery. Factor analysis with varimax rotation was applied to the neuropsychological test scores, to yield five factors from 16 original scores, which explained 82 % of the total variance. Correlations between cognitive factors and 18F-DOPA uptake were assessed with SPM8, taking age and gender as nuisance variables.
18F-DOPA uptake was significantly lower in PD patients than in controls in the bilateral striatum, mainly in the more affected (right) hemisphere, and in a small right temporal region. Significant positive correlations were found only in PD patients between the executive factor and 18F-DOPA uptake in the bilateral anterior cingulate cortex (ACC) and the middle frontal gyrus, between the verbal fluency factor and 18F-DOPA uptake in left BA 46 and the bilateral striatum, and between the visuospatial factor and 18F-DOPA uptake in the left ACC and bilateral striatum. No correlations were found between 18F-DOPA uptake and either the verbal memory factor or the abstraction–working memory factor.
These data clarify the role of the mesocortical dopaminergic pathways in cognitive function in early PD, highlighting the medial frontal lobe, anterior cingulate, and left BA 46 as the main sites of cortical correlation with executive and language functions.
Keywords18F-DOPA PET Parkinson’s disease Mesocortical pathway Cognitive impairment Neuropsychology
Compliance with ethical standards
This was an unfunded study.
Conflicts of interest
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
This article does not describe any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.