Clinical characteristics of cognitive impairment in patients with Parkinson's disease and its related pattern in ¹⁸F‐FDG PET imaging

Abstract

This study aimed to characterize the clinical features and the related cerebral glucose metabolism pattern of cognitive impairments in Parkinson's disease (PD) with positron emission tomography (PET) imaging. We recruited 168 PD patients and 100 age-matched healthy controls of similar education and gender distribution. All of those enrolled underwent clinical assessment including the unified Parkinson's disease rating scale motor score, Hoehn and Yahr scale, and comprehensive neuropsychological tests including domains of executive function, attention, memory, visuospatial function, and language. Demographics and the results of cognitive measures were compared between patients and healthy controls. Cognition status was classified as PD patients with dementia (PD-D), PD patients with mild cognitive impairment (PD-MCI), or PD patients with normal cognition (PD-NC). In 53 PD patients who underwent F-fluorodeoxyglucose ( F-FDG) PET imaging, correlations between Z-score values of the different cognitive domains and cerebral F-FDG uptake were assessed using statistical parametric mapping (SPM8) corrected for age and motor severity. A total of 23.2% of PD patients were PD-MCI and 8.9% were PD-D. In the group of PD-MCI, 96.3% showed multiple-domain deficits, with executive function and attention impairment most predominantly involved. All the cognitive domain scores with the exception of language correlated with F-FDG metabolisms, primarily in posterior temporo-parieto-occipital association cortical areas. This study found that cognitive impairment in PD particularly encompasses frontal/executive deficits. Posterior cortical areas, containing multiple neurotransmitters and neural circuits, may play an important role in the pathogenesis of cognitive impairment in PD.

Preserved caudate function in young-onset patients with Parkinson’s disease: a dual-tracer PET imaging study

“…Putamen-related motor circuits were responsible for motor functions, and disruption of putamen function correlated well with the onset of cardinal motor symptoms 34 and motor severities, 10,35 whereas caudate was more likely to be involved in the circuits related to cognitive and affective functions. 36–38 Patients with caudate lesion suffered from cognitive changes, including poor planning and sequencing. 39 In the current study, DAT binding in caudate correlated moderately with TMT-A test scores.…”

Correlations of Neuropsychological and Metabolic Brain Changes in Parkinson's Disease and Other α-Synucleinopathies

“…Deficits of executive functions correlated with frontal hypometabolism in some studies (92, 93), but not in the others (94–96). Furthermore, disruption of the striatal dopaminergic system, shown with [ 18 F]-6-fluorodopa PET imaging, correlated with executive dysfunction in patients with preserved metabolism in the frontal cortex (97), with uncertain explanation.…”

“…Hypometabolism in parietal and temporal cortices more consistently correlated with executive dysfunction (92–96). Attention deficits, regarded by some as an executive dysfunction (99), correlate with hypometabolism in the frontal cortex (95), precuneus and parietal cortex (94) and with the hypermetabolism in the putamen, parahippocampal gyrus, inferior frontal lobule, paracentral lobule, and hippocampus (94). Posterior cholinergic neurodegeneration, marked by the initial decline in visuospatial functioning and followed by memory impairment, can be detected by glucose metabolism changes, too.…”

“…Posterior cholinergic neurodegeneration, marked by the initial decline in visuospatial functioning and followed by memory impairment, can be detected by glucose metabolism changes, too. The former deficits correlate with the occipito-parietal, temporal and precuneal hypometabolic changes (94, 96), but also with the putaminal and parahippocampal hypermetabolism (94). Memory deficits correlated with the temporal and parietal hypometabolism (92, 94, 95).…”

Early diagnosis of Parkinson’s disease using EEG, machine learning and partial directed coherence

“…One study pointed out that regions related to visual processing such as parietal and frontal lobes are altered in patients with cognitive decline associated with PD (Mak et al 2015). Wu et al (Wu et al 2018) found a correlation between the reduction of glucose metabolism in the parietal, temporal, frontal, and cingulate cortex and the pathological pattern of PD using positron emission tomography (PET). These data reinforce our findings, raising the possibility of a new PD biomarker related to visual processing.…”