The closing-in phenomenon occurs when a drawing is reproduced close, next or partially superimposed on the original model, despite a clear consign to do not do so. This behavior has been often reported in patients with Alzheimer disease. However, patients with other forms of dementia (Parkinson’s associated dementia, vascular dementia, Lewy body disease) can reproduce the closing-in phenomenon in an uncontrollable manner.
Some patients with advanced Alzheimer disease whom I remember superimposed exactly the copy on the model. The cerebral mechanisms at the origin of the closing-in phenomenon is still a matter of debate. However, the closing-in phenomenon should be elicited in a standardized way, which has not been always the case in the published studies.
For some authors the closing in phenomenon is the result of a compensatory strategy that patients adopt to compensate wisuospatial deficits. For other authors the CI phenomenon could be explained by a magnetic attraction (similar to a grasping phenomenon) to the model (which could correspond to a sort of frontal release sign). Both mechanisms could be true.
However, patients can improve their performance and the quality of drawing when they have to reproduce the stimulus without a model to copy, a situation, which seems to point out the hypothesis of an attraction mechanism. However, that one is not a definitive evidence.
Actually, in my experience, patients with severe dementia and other marked frontal signs (especially motor perseveration or environmental dependency syndrome) have the best chance to exhibit this behavior in an uncontrollable way. Thus, my personal opinion is that this phenomenon is moreover a pathological grasping variant (magnetic copy or magnetic attraction).
It would be interesting to assess patients’ copying abilities with stimuli with emotional different salience in order to enhance or to reduce the attraction to the model.
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