The neurological basis of visual neglect

Abstract

A recent study has confirmed the enormous impact of visual neglect on the health services of the western world. Neglect was present in 48% of a sample of 166 right hemisphere stroke patients, and the severity of neglect predicted the extent of functional disability and family burden more accurately than did the extent of brain damage. Given the medical significance of neglect and its tantalizing relevance to understanding human conscious experience, it is unsurprising that the neuropsychological literature concerning the syndrome continues to grow rapidly. We include brief surveys of six topics currently attracting attention in the field: the anatomical focus of neglect; the visual input pathways implicated; impairments of spatial working memory; the nature of visual extinction; perceptual distortions in neglect; studies on healthy subjects using transcranial magnetic stimulation; and the use of prism adaptation for the rehabilitation of neglect. There is steady progress in understanding the essential components of neglect and their brain localization. Every step towards clarity, however, seems to be matched by a new discovery of the inherent complexity of the syndrome. The clinical expression of neglect may reflect the interaction of a variety of spatially lateralized and non-lateralized impairments, not all of which are present in all patients. The quest for an effective technique for the clinical rehabilitation of neglect continues, with prism adaptation emerging as the most promising approach to date.