Objective: To measure the expression of the Parkinson’s disease related cognitive pattern (PDCP) in 18F-FDG-PET brain images of Parkinson’s disease (PD) patients and healthy controls (HC) and to validate its correlation with subjects’ performance on cognitive tests.

Background: PDCP has been identified using a spatial covariance technique known as scaled subprofile model (SSM) based on principal component analysis (PCA) on 18F-FDG-PET images. It consists of covariate metabolic reductions in frontal and parietal association areas and relative increases in the cerebellar vermis and dentate nuclei. It has been shown that PDCP correlates with PD patients’ cognitive performance.

Methods: 18F-FDG-PET brain images of 20 non-demented PD patients (68±6 yrs old, 4±3 yrs PD duration, MDS-UPDRS-III: 38±10, MMSE: 29±2, MoCA: 26±3) and 20 HC (66±6 yrs old, MMSE: 29±1, MoCA: 27±2) were acquired. Different cognitive functions were assessed: attention (Trail making Test (TMT), verbal and non verbal memory (California Verbal Learning Test (CVLT II), Rey Complex Figure Test and Recognition Trial (RCFT)), visuospatial and visuoconstructional abilities (Rey Complex Figure (RCFT)), language (Verbal fluency test) and executive functions (Stroop Test, Tower test). The subject scores representing expressions of PDCP were calculated in the scans of individual subjects using Topographic Profile Rating (TPR). Correlations between PDCP subject scores and corresponding scores of each neuropsychological test were assessed by computing Pearson correlation coefficient.

Results: The expression of PDCP was significantly increased in PD patients compared to HC (p<0.001). PDCP expression correlated significantly with MoCA score in PD patients (R2=0.31, p=0.01). PDCP expression correlated significantly with attention (p<0.05, TMT Trial A) and s executive functions (p<0.05, Stroop test; p<0.05, TMT Trial B). Moreover, PDCP expression significantly correlated with learning curve (p<0.05), short delay free recall (p<0.05), and long delay free recall (p<0.05) measured by CVLT II. However, correlation between language and visuospatial abilities failed to reach significance.

Conclusions: PDCP has shown to be a reproducible imaging marker of cognitive dysfunction in PD. It correlates well with global cognitive score as well as with more specific, predominantly frontal cognitive domains.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/metabolic-brain-changes-related-to-specific-cognitive-impairment-in-non-demented-parkinsons-disease-patients/