Strategy for the copy task of Rey-Osterrieth Complex Figure: how response disinhibition deteriorates it in Alzheimer's disease

<p>Objective: To qualitatively analyze the order of copying the Rey-Osterrieth Complex Figure (ROCF) elements and evaluate the relationship between response disinhibition and inappropriate strategy for copying in Alzheimer's disease (AD). Subjects: 40 AD patients who underwent Alzheimer's Disease Assessment Scale (ADAS), Frontal Assessment Battery (FAB), and the copy task of the ROCF, with perfect performance on the Construction of the ADAS. Methods: We defined 20 elements of the ROCF. We classified patients based on the order of copying: Group A who started the task with drawing and completing the large rectangle (Configural Element A); Group B who started the task with drawing Configural Element A but, before completing it, also drew and completed another element; Group C who started the task with drawing and completing an element other than Configural Element A; and Group D who were not classified into any of the 3 groups above because no element was completed. We considered the combined Group B and C as the patients who were distracted by an inappropriate element for strategic copy order, and compared them with patients in Group A for patient, disease and cognitive characteristics by analysis of covariance with the MMSE score and education attainment as covariates. Results: We classified 26 patients into Group A, 3 into Group B, 10 into Group C, and 1 into Group D. The score on the Go No-go task of the FAB was significantly lower in Group B and C than in Group A. Discussion: After controlling for the factor of construction disorder, almost all patients who did not copy ROCF in a well-planned and reasonable order comprised Group C (who were distracted by an strategically inappropriate element at the start of the task) and Group B (who started the task with drawing the appropriate element but, before completing it, were distracted by another element), and they showed lower performance on the Go No-go task of response inhibition. These results support the hypothesis that patients with deteriorated response inhibition cannot suppress the distraction of an inappropriate element for copying strategy resulting in poorly-planned and less efficient strategy for copying.</p>