Anatomical Correlates of the "Closing-In" Phenomenon

Background and PurposeThe “closing-in” phenomenon refers to the tendency to copy near or overlap a model while performing figure-copying tasks. The mechanisms underlying the closing-in phenomenon have not been fully elucidated, and previous studies only investigated the mechanisms through neuropsychological tests. We investigated the neuroanatomical correlates of the closing-in phenomenon using voxel-based morphometry (VBM). MethodsThirty-eight patients diagnosed with probable Alzheimer’s disease (AD) and 21 normal controls were included. All subjects underwent neuropsychological testing to diagnose dementia and magnetization prepared rapid acquisition gradient echo brain magnetic resonance imaging for the voxel-based statistical analysis. The subjects were asked to copy the modified Luria’s alternating squares and triangles to quantify the closing-in phenomenon. We applied SPM8 for the VBM analysis to detect gray matter loss associated with the closing-in phenomenon. ResultsThe patients with probable AD showed a higher closing-in score than that of the normal control subjects (p