Distance-mediated spatial neglect.

ABSTRACT

Unilateral spatial neglect (USN) is usually assessed by means of individual stimuli or single arrays of stimuli. Seldom are stimuli presented as multiple objects or in spatially separated blocks, except in some tests for object-based neglect. The distance between individual objects or blocks of stimuli in such stimuli is implicitly considered irrelevant. We report on the case of a patient, EC, who showed severe USN in his everyday behavior, yet performed normally on standard tests for USN. Presented with stimuli in separate blocks, he performed flawlessly with 4 cm gaps between blocks, yet ignored all leftward blocks of stimuli when the gap was larger than this. EC's dissociation between good performance on standard tasks and severe neglect with separate groups of stimuli, and the distance-mediated nature of his USN are novel observations with relevant theoretical and clinical implications.