Changes in regional cerebral blood flow associated with psychosis in patients with Alzheimer’s disease

OBJECTIVE: To identify changes in regional cerebral blood flow (CBF) associated with psychosis in patients with Alzheimer's disease (AD) through arterial spin labeling (ASL) magnetic resonance imaging (MRI). METHODS: Sixty patients with AD, whose diagnoses were supported by amyloid PET, were recruited. A set of neuropsychological tests was used to evaluate cognitive function and neuropsychiatric symptoms. All participants were assigned to either the AD with psychosis (AD-P) group or the AD without psychosis (AD-NP) group according to their hallucination and delusion scores on the Neuropsychiatric Inventory (NPI). Regional CBF was measured using pseudocontinuous ASL MRI in the resting state. RESULTS: Compared with AD-NP patients, AD-P patients achieved lower scores on the Mini-Mental State Examination (MMSE) and on the cognitive domains of memory and visuospatial function; they also exhibited worse performance in terms of daily function. Compared with the AD-NP group, the AD-P group exhibited significantly lower global CBF. After the global values normalized, relatively lower CBFs were detected in the left middle temporal gyrus, right supramarginal gyrus and bilateral precuneus in patients with AD-P. Lower CBF in the precuneus was correlated with both cognitive impairment and hallucinations. CONCLUSION: Psychosis was associated with more severe cognitive impairment and lower CBF in regions of the temporal and parietal lobes, particularly the precuneus, in AD patients.