Differences in responses to the Rorschach test between patients with dementia with Lewy bodies and Alzheimer's disease -from the perspective of visuoperceptual impairment

Patients with Dementia with Lewy bodies (DLB) tend to perform worse in tasks on visuoperception than patients with Alzheimer's disease (AD). The Rorschach inkblot test has its utility for assessing perceptual and visuospatial abilities. In this study, we examined the differences in responses to the Rorschach test between patients with DLB and those with AD in terms of visuoperception, and investigated the utility of the test for assessing visuoperceptual impairment in DLB. Using the comprehensive system of Rorschach test, six variables were significantly higher, and three variables were significantly lower in DLB patients compared to AD patients. Among those variables, PTI showed high sensitivity and specificity for differentiating DLB from AD. Furthermore, when the PTI score was combined with the Dd score and a number of times a patient saw an eye in a shading part of an inkblot, the sensitivity and specificity reached 90.6% and 73.1%, respectively. These results indicate that the patients with DLB perceive objects in the inkblot differently from patients with AD, and suggest that some variables of the Rorschach test could assist with neuropsychological examinations when differentiating DLB from AD.