MRI brain scan analyses and neuropsychological profiles of nine patients with persisting unilateral neglect.

Systematic individual neuroanatomical (MRI) and neuropsychological investigations were conducted for nine patients with unilateral neglect persisting at least 3 months after a cerebral vascular accident. The pattern of referrals, together with subsequent investigation, demonstrates that persisting neglect is rare in both right- and left-hemispheric lesioned patients. But while persisting neglect following a left-hemispheric lesion is even rarer than following a right-hemispheric lesion, it does occur. The neuroanatomical results indicate that persisting neglect may be associated with a different pattern of damage from acute neglect. In the nine patients investigated, persisting neglect reflected extensive lesions that involved three or more cortical lobes or subcortical regions. The results support previous findings that parietal lesions are common but not essential for persisting neglect. In the seven of nine neglect patients with parietal lesions, the rostral inferior parietal lobe and the parietal-frontal junction were involved. Of note was the finding that the brain regions most commonly implicated were the basal ganglia and the superior dorsolateral prefrontal cortex (including the frontal eye field). All of the patients with persisting neglect had a range of neuropsychological deficits, including extinction, personal neglect, and anosognosia for one or more aspects of their neglect. Although it was not possible to demonstrate a double dissociation with this pattern of results, the findings indicate that extinction and anosognosia are dissociable into function-specific forms. Most of the neglect patients also had sustained attention deficits, visual memory problems, and visuospatial constructional difficulties.