Processing fragmented forms and strategic control of orienting in visual neglect
Humphreys GW., Boucart M., Datar V., Riddoch MJ.
A single case study is reported of a patient with a right parietal lesion who showed: (1) clinical left neglect; (2) poor report of right-field items in identifying bilateral simultaneously presented stimuli; and (3) particularly poor processing of fragmented forms within his left visual field. We suggest that, in this patient, neglect is related to an impairment in orienting attention to contour information following his right-hemisphere lesion. This is exacerbated by the use of fragmented forms, but can be overcome by strategic allocation of attention to the left under bilateral presentation conditions. Neglect of the left, and extinction for right-side stimuli, reflect unbalanced competition on the attentional orienting system due respectively to (1) poor perceptual processing and (2) strategically attending to the left side of space.