Focal and global visual attention in left visuo-spatial neglect

Abstract

Visuo-spatial neglect can be conceptualized as a failure of right hemisphere global attentional systems to direct the visual processor of the left hemisphere uniformly across an array. Two patients have recently been reported who show a dissociation of preserved global visual form perception in the context of left neglect for constituent elements. We present the first longitudinal study of the phenomenon which confirms that this pattern of neglect is associated with extensive right hemisphere damage, is fairly stable over time and may persist up to one year post insult. The use of modified Navon figures suggests that task demands may be significant in the manifestation of neglect. Correlation with conventional diagnostic tests for neglect is poor, but results suggest a subgroup of Navon stimuli that may be particularly sensitive to clinical change.