Delusions and dementia: clinical and CT correlates

INTRODUCTION: Delusions occur frequently during the course of Alzheimer's disease (AD) and multi-infarct dementia (MID). Their clinical significance and their relationship with progression of disease and involvement of selected cerebral areas are still unclear. The aim of the study was to determine the clinical and CT correlates of delusions in patients with dementia. MATERIAL AND METHODS: A series of 67 probable AD and 32 MID patients, underwent computed tomographic scans, psychometric tests, neurologic and psychiatric examination, and blood and serum tests. RESULTS: Twenty-four patients were found to have delusions during the clinical evaluation. Delusional patients showed a significantly higher age when compared with non-delusional patients. The results of a multiple logistic regression (with stepwise deletion of the redundant variables) of the CT lesions on the presence of delusions, showed that only the presence of isolated white matter lesions in the frontal lobes were significantly related to the occurrence of delusions (Exp B = 3.42; Beta = 1.2; S.E. = 0.6; Sig T = 0.04). Frontal white matter changes were significantly related to delusions when a multiple regression analysis, entering age and total number of lesions at CT scans, was carried out. CONCLUSIONS: We found that focal lesions in the frontal areas were the only variable that appeared to be significantly and independently associated with delusional disorders.