Closing-In Behavior and Motor Distractibility in Persons with Brain Injury

Objective: This study investigates closing-in behavior (CIB), a phenomenon observed in graphic copying tasks when responses encroach upon or overlap the model. The behavior is most common amongst individuals with dementia and amongst pre-school children. We explored the relationship between CIB and the 'distractor effect' in reaching, whereby salient visual stimuli can influence the spatial trajectory of the reach. Method: A group of individuals with overlap-CIB (n = 9), without CIB (n = 9) and healthy controls (HC; n = 6) underwent a task-irrelevant and a task-relevant distractors and the deviation of the movement trajectory towards the distractor location was measured in both tasks. Results: Individuals with graphic CIB showed more distractor-directed veering during reaching than did individuals without CIB or HC, provided that the distractor was relevant for the reaching task. Conclusions: These results strengthen the relationship between CIB and the distractor effect and reinforce the hypothesis that CIB represents a disinhibited tendency to act towards the focus of attention.