Discordant Performances on The Cube Copying Test (CCT) and The Pentagon Copying Test (PCT)

Abstract

  Visuo-constructive impairment is a characteristic of Alzheimerʼs disease (AD) and dementia with Lewy bodies (DLB) . Visuo-constructive impairment is often assessed with the cube copying test (CCT) and the pentagon copying test (PCT) . However, the performance of CCT and PCT is not always consistent in all patients. Thus, we investigated the specificity of the two tasks by analyzing the patients with neurocognitive disorders who succeeded solely in one of the two tasks. Subjects were 672 patients who were initially diagnosed with dementia or suspected of having dementia. Success and failure on the tasks were operationally determined. Of enrolled patients, 404 subjects (60.1% ) succeeded in both tasks, 103 subjects (15.3% ) failed in both. Fifty subjects (7.4% ) succeeded in CCT but not PCT, and 115 subjects (17.1% ) succeeded in PCT but not CCT. In VaD and FTLD, there were significantly more subjects who succeeded in PCT but not in CCT than subjects who succeeded in CCT but not PCT. In AD and DLB, there were no significant difference in the two groups.