Abstract
Delusions of theft (delusions involving the theft of possessions) are one of the most frequent neuropsychiatric manifestations of Alzheimer's disease (AD). AD patients with delusions of theft showed significant hypoperfusion in the right medial posterior parietal region (precuneus) compared to patients without delusions. Our study suggests that there is no association between delusions of theft and cognitive impairments assessed by ADAS-Jcog. Precuneus is a key part of the neural substrate of visual imagery occurring in conscious memory recall. It is also related to a functional network of episodic source memory. AD patients with precuneus dysfunction might have difficulties in recalling the place where they put their belongings or in recalling contextual association between their belongings and the place where they put them. There is also the possibility that these patients might have difficulties in recalling the acts to put their belongings on somewhere. My hypothesis about the mechanism producing delusions of theft in patients with AD is that, based on these memory impairments related with precuneus dysfunction, psychosocial factors cause secondary delusional beliefs to arise. In future study, it will be essential to use specialized neuropsychological tests that assess these specific memory impairments.
