Associations between plasma ceramides and cognitive and neuropsychiatric manifestations in Parkinson's disease dementia

The abnormal metabolism of ceramides may account for the pathogenesis of Parkinson's disease dementia (PDD). However, the effect of ceramides on cognitive domain impairments and neuropsychiatric symptoms of PDD remains unknown.A total of 38 PDD, 40 PD with no cognitive impairment (PD-NC) and 40 normal controls were included. A series of cognitive tests and the Neuropsychiatric Inventory (NPI) were used to assess cognitive domains and neuropsychiatric symptoms. A non-fasting blood sample was obtained from each subject. Plasma ceramide levels were tested by HPLC-MS/MS analysis.C14:0 and C24:1 levels were significantly higher in PDD than in PD-NC and normal controls. Verbal memory was negatively correlated with C14:0 and C24:1. After controlling for confounding factors, C22:0, C20:0 and C18:0 were significantly associated with hallucinations, anxiety and sleep behavior disturbances, respectively.In PDD, the increase in ceramide levels was correlated with decreased memory function and associated with higher odds of multiple neuropsychiatric symptoms.