Axis-based neglect of visual shapes.

A new test of "object-centered" visual neglect uses equilateral triangles, with ambiguous principal axes that can be manipulated by context. Three left neglect patients detected gaps in such triangles. The location of the gap relative to the biased principal axis was varied, while maintaining the same egocentric locus. More gaps were missed on the left of the axis. This supports Driver and Halligan's (Cognit. Neuropsychol. 8, 475-496, 1991) claim that neglect can apply to the contralesional side of a shape's principal axis, while avoiding serious flaws in their method. The relation between axis-based neglect and other cases of object-centred neglect is discussed.