Cognitive performances and DAT imaging in early P arkinson's disease with mild cognitive impairment: a preliminary study

Objectives Mild cognitive impairment ( MCI ) is a common feature in P arkinson's disease ( PD ). We performed an exploratory study to investigate dopaminergic nigrostriatal innervation and its cognitive correlates in early untreated PD patients with MCI as compared to cognitively intact patients. Patients and methods A consecutive series of 34‐ de‐novo , drug‐naïve patients with PD were enrolled. They underwent [123‐ I ] FP ‐ CIT SPECT and comprehensive neuropsychological battery. MCI was identified in 15 of 34 patients with PD . Results The two groups did not show any statistically significant difference in age, sex, disease duration, education, lateralization, and H & Y and H ospital A nxiety and D epression S cale scores. Logistic regression analysis showed that UPDRS ‐ III was weakly associated with MCI ( P  = 0.034). Partial correlation analysis controlling for UPDRS ‐ III and age suggested that in PD patients with MCI reduced V 3″ values in the more affected caudate were correlated with reduced performances in frontal assessment battery, T rail M aking T est: part B minus P art A and copy task of the R ey– O sterrieth complex figure test. Reduced V 3″ values in the more and less affected putamen were significantly related with reduced performance in frontal assessment battery and in copy task of R ey– O sterrieth complex figure test, respectively. No correlation was found between neuropsychological scores and DAT availability in PD patients without MCI . Conclusions Although preliminary, our results suggest that striatal dopamine depletion may contribute to some cognitive deficit in early never treated PD patients with MCI .