Cerebral metabolic change in Parkinson's disease patients with anxiety: A FDG-PET study

To detect the cerebral metabolic bases of Parkinson's disease (PD) patients with anxiety.

Totally 28 idiopathic PD patients without depression (17-item Hamilton Depression Rating Scale, HAMD score <14) were enrolled in our study. All subjects were classified into PD with anxiety (PD-A) (n=13) and PD without anxiety (PD-NA) (n=15) by cutoff score of 11 according to Hamilton Anxiety Rating Scale (HAMA). Besides, age- and gender- matched healthy controls (HCs) (n=15) were selected. A resting-state F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scan was applied to estimate cerebral metabolic activity. All statistical analyses were performed using IBM SPSS Statistics V20.0.0 software, while statistical parametric mapping software (SPM) was used to analyze the FDG-PET images.

PD-A showed decreased glucose metabolism in the bilateral orbitofrontal cortex (OFC, BA10 and BA11) when compared with PD-NA. Significant decrease of cerebral glucose metabolism in the bilateral OFC, bilateral supplementary motor area (SMA, BA6), bilateral dorsal anterior cingulate cortex (dACC, BA32), right dorsolateral prefrontal cortex (dlPFC, BA9), right ventrolateral prefrontal cortex (vlPFC, BA44), right putamen and left caudatum was detected in PD-A compared with HCs. There was significant reduced glucose metabolism of the bilateral SMA in PD-NA when compared with HCs (uncorrected p<0.005).

The anxiety of PD was associated with the metabolic reductions of PFC and striatal areas. OFC, part of PFC, could be taken as a characteristic feature for anxiety in PD. This metabolic pattern suggested that deficits of prefrontostriatal pathways might affect anxiety mood in PD.