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.

Closing-in behavior: Compensation or attraction?

OBJECTIVE: Closing-in behavior (CIB) defines the abnormal misplacement of the copy performance, positioned very closed to or on the top of the model. This symptom is observed in graphic copying by patients suffering from different neurological diseases, most commonly dementia. The cognitive origins of this behavior are still a matter of investigation, and research of the last 10 years has been focused on exploring 2 main accounts of CIB, the compensation and the attraction hypotheses, providing evidence in both directions. While the first account defines CIB as a compensatory strategy to overcome visuospatial and/or working memory deficits during copying tasks, the attraction hypothesis looks at CIB as primitive default behavior in which attention and action are closely coupled and movements are performed toward the focus of attention. METHOD: We explored these 2 hypotheses in a sample of patients with and without CIB, and controls in 5 experiments: Experiments 1 and 2 tested the attraction hypothesis and, respectively, the prediction that CIB can be elicited in a noncopying dual task condition loading upon attentional resources or by irrelevant attentional grabbing stimuli. The other experiments investigated the compensation hypothesis manipulating the distance between model and copying space (Experiment 3), the task demand (single or dual task loading on verbal working memory; Experiment 4), the task requirements (copying and tracing) and visual demand (visual copy and memory; Experiment 5). RESULTS: The results support the attraction hypothesis of CIB. CONCLUSIONS: CIB reflects an impairment of the attention and action system, rather than a compensatory strategy. (PsycINFO Database Record