This article includes discussion of neglect, amorphosynthesis, dyschiria, hemi-inattention, hemineglect, hemispatial neglect, unilateral neglect, unilateral spatial neglect, visual neglect, visuospatial neglect, anosognosia, and extinction. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.
Unilateral spatial neglect, or “neglect” for short, commonly follows the acute onset of focal hemispheric brain disease, but may also appear in progressive cerebral degeneration. It involves a directional bias of spatial attention that is usually toward the side of brain injury, thus neglect for the opposite side of space, including part of one’s body. This article indicates that neglect is distinct from other hemibody deficits of movement (hemiparesis) or perception (hemianopia, hemianesthesia) because the spatial deficit can be overcome by cuing or increasing motivation, such as through reward. Nonetheless, the disorder commonly signifies a profound impairment in recovery of self-care abilities. Acute slowed responses on visual attention testing can predict persisting unilateral neglect years later. Efficacious treatment has not yet been developed.
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• Neglect is a common consequence of focal brain injury.
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• Neglect is easily assessed with bedside evaluations.
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• Neglect commonly predicts impaired recovery of self-care after brain injury, although it is not yet clear whether functional impairment is primarily from neglect itself or from other, concurrent cognitive deficits.
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• Neglect tends to improve in most persons following acute brain injury, but chronically can remain in a small proportion of patients.
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• No standard of rehabilitation care has thus far been developed for neglect.
Historical note and terminology
Neglect appears to have not received the same scrutiny in the 19th century as the aphasias, agnosias, and apraxias. Late 19th century experiments in laboratory mammals induced asymmetric behavior that could not be accounted for by hemiblindness or hemiparesis (14; 53; 135). In the 1880s, Loeb obtained asymmetric responses to bilateral simultaneous stimulation (extinction) in animals, which was quickly confirmed in humans by Oppenheim (Benton 1956). In 1865, Prevost reported that Vulpian had found contralesional conjugate eye deviation following brain injury in humans (66), which if not precisely neglect, is closely related. Jackson reported a British patient whose right hemisphere tumor was associated with a right-to-left reading approach to an eye chart, which the patient could not explain (89). In the early part of the 20th century, Zingerle described neglect as a disorder of spatial representations (219). Poppelreuter, and then Brain, emphasized the role of spatial attention in the underlying deficit in neglect (142; 25). In the 1950s, Denny-Brown introduced the notion of "amorphosynthesis," meaning that patients with neglect were unable to synthesize contralateral stimuli into coherent percepts (48). Systematic theoretical approaches to neglect emerged in the 1970s.