The Closing-in Phenomenon in Alzheimer's Disease and Vascular Dementia

BACKGROUND AND PURPOSE: The closing-in phenomenon is the tendency to draw near or on the target when copying figures, which has been found mostly in patients with Alzheimer's disease (AD). We attempted to quantify the degree of closing-in and to compare it between patients with AD and vascular dementia (VaD). METHODS: The subjects (55 AD, 39 VaD and 38 normal controls) were asked to copy the figure of alternating square and triangle, starting at the designated point and continuing from left to right. The patients with AD and VaD did not differ in age, education, severity of dementia or Rey Complex Figure Test copy score. The proximity (Y-axis) of the subject's drawing to the target was plotted at intervals of 2 mm along the X-axis and the degree of closing-in was computed from the slope of the regression line. RESULTS: The AD and VaD patients showed a steeper slope than the controls. There was no significant difference, however, in the magnitude of closing-in of the AD and VaD patients. When closing-in was defined as a slope that was greater than the mean+2SD of the slope observed for the controls, 32.7% of the AD and 25.6% of the VaD patients showed closing-in. CONCLUSIONS: Our study, using a new method of measuring the degree of closing-in, suggests that this phenomenon is not specific to AD.