A clinical study on closing-in in focal brain-damaged individuals

In visuo-constructional assessment, brain-damaged individuals may copy figures near to or superimposed on the model, showing the Closing-in (CI). CI has been largely investigated in dementia, and often ascribed to impairments of the attention/executive abilities ("Attraction hypothesis"). Only a few dated studies investigated frequency of CI in brain-damaged individuals, without clarifying the genesis of the phenomenon. We aimed at testing the "Attraction hypothesis" in 27 individuals with focal frontal cortical or sub-cortical brain lesions by a dual-task experimental paradigm. The participants underwent a neuropsychological battery and a copying task to be performed alone (single task condition), or concurrently with a simple or a complex verbal secondary task (dual-task conditions). CI was found in 66% of frontal-damaged individuals, who scored significantly lower than healthy adults on all neuropsychological measures; brain-damaged individuals showing CI performed worse than frontal-damaged individuals without CI on frontal and visuo-constructional measures. In the dual-task condition with the complex secondary task CI was significantly enhanced, with a weaker tendency to self-correction, in individuals with CI compared to individuals without CI. These findings would confirm that the CI in brain-damaged individuals is related to reduction of attentional resources, consistently with the "Attraction hypothesis".