Spatial neglect: clinical and neuroscience review: a wealth of information on the poverty of spatial attention

Abstract

Hemispatial neglect (HSN) is a frequent, conspicuous neurobehavioral accompaniment of brain injury. Patients with HSN share several superficial similarities, leading earlier clinical neuroscientists to view neglect as a unitary condition associated with brain structures that mediate relatively discrete spatial cognitive mechanisms. Over the last two decades, research largely deconstructed the neglect syndrome, revealing a remarkable heterogeneity of behaviors and providing insight into multiple component processes, both spatial and nonspatial, that contribute to hemispatial neglect. This review surveys visual HSN, presenting first the means for detection and diagnosis in its manifold variations. We summarize cognitive operations relevant to spatial attention and evidence for their role in neglect behaviors and then briefly consider neural systems that may subserve the component processes. Finally, we propose several methods for rehabilitating HSN, including the challenges facing remediation of such a heterogeneous cognitive disorder.

Figure 1

Patient with neglect after right brain injury fails to mark contralesional “A” targets in array of letters (A) and omits contralesional aspects of rendered figure (B).

Figure 2

Patient with neglect after right hemisphere stroke positions west coast states [California (CA) and Oregon (OR)] on the right half of a contour of the United States, consistent with a rightward bias in spatial representation.

Figure 3

(A) Viewer-centered neglect: patient correctly circles complete figure and cancels incomplete figures on contralesional side of the array (similar to Fig. 1A). (B) Object-centered neglect: patient marks targets on both sides of the array but incorrectly identifies incomplete figures (lacking a leftsided segment) as complete.

Figure 4

Cortical sites implicated in spatial attention, including their putative specialization and distance/reference frames suggested in human lesion studies. TPJ, temporoparietal junction; STG, superior temporal gyrus; MFG, middle frontal gyrus; IFG, inferior frontal gyrus.