Anosognosia versus unilateral neglect. Coexistence and their relations to age, stroke severity, lesion site and cognition.

The aim of this study was to examine the association between anosognosia and unilateral neglect (UN), with special focus on age, stroke severity, lesion location and pre-stroke dementia. The basis of this investigation was a population-based stroke incidence study. Anosognosia was assessed using a questionnaire, and UN using a three-item version of the Behaviour Inattention Test, the Baking Tray Task and a test of personal neglect. Stroke severity was assessed using the NIH stroke scale. Patients with anosognosia were older, and they more often had pre-stroke dementia than patients having UN only. No particular lesion localization was associated with anosognosia, while UN was strongly associated with previously defined lesion sites, often in the parietal lobe. There was a borderline significance regarding stroke severity in patients having anosognosia compared with those with UN only. Patients with anosognosia had higher mortality than patients without, but when controlled for age and stroke severity, this effect was not independent. While UN is closely associated with 'classical' lesion sites, anosognosia is a condition that more often occurs in a previously impaired brain. For anosognosia, lesion location appears to be less important. Anosognosia also tends to occur with larger strokes.