The Bender Gestalt Test is useful for clinically diagnosing dementia with Lewy bodies: Analysis of its sensitivity, specificity, and clinical characteristics of the figure copy.

A previous study that evaluated the ability of the Bender Gestalt Test (BGT) to discriminate between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) suggested that a total score of 98 is the optimal cutoff value for discriminating between these two diseases and that DLB tends to exhibit unique errors; i.e., "element deformation" and "gestalt destruction." The objectives of the present study were: (1) to examine the sensitivity and specificity of a total BGT score of 98 as a cutoff value in greater numbers of DLB patients than in the previous study, (2) to set a new cutoff value if a cutoff value of 98 is not optimal, and (3) to clarify the frequency of element deformation and gestalt destruction in DLB patients. The participants were 133 DLB patients, 65 AD patients, and 30 cognitively normal elderly people. All of the participants underwent the Mini-Mental State Examination, BGT, and brain magnetic resonance imaging. As a result, the total BGT score cutoff value of 98 showed low sensitivity (0.58), and a cutoff value of 84 was indicated to be the optimal cutoff value for discriminating between DLB and AD. In addition, 32 out of 133 DLB patients and one out of 65 AD patients exhibited element deformation or gestalt destruction. This study suggested that the BGT is a useful neuropsychological test for differentiating DLB from AD. In addition, the need to evaluate the spatial and perceptual difficulties of DLB patients with various types of visual stimulation is also discussed.