Unilateral neglect and perceptual parsing: a large-group study.

Array-centred and subarray-centred neglect were disambiguated in a group of 116 patients with left neglect by means of a modified version of the Albert test in which the central column of segments was deleted so as to create two separate sets of targets grouped by proximity. The results indicated that neglect was more frequent in array- than subarray-centred coordinates and that, in a minority of cases, neglect co-occurred in both coordinate-systems. The two types of neglect were functionally but not anatomically dissociated. Presence of visual field defects was not prevalent in one type of neglect with respect to the other. These data contribute further evidence to previous single-case and small-group studies by showing that neglect can occur in single or multiple reference frames simultaneously, in agreement with current neuropsychological, neurophysiological and computational concepts of space representation.