Dissociating ego- and allocentric neglect after stroke: prevalence, laterality and outcome predictors

Abstract

Visuospatial neglect is a neuropsychological condition commonly experienced after stroke, whereby a patient is unable to attend to stimuli on their contralesional side. We aimed to investigate whether egocentric and allocentric neglect are functionally dissociable and differ in prevalence, laterality and outcome predictors. A consecutive sample of 366 acute stroke patients completed the Broken Hearts test from the Oxford Cognitive Screen. A subsample of 160 patients was followed up 6 months later. We evaluated the association between egocentric and allocentric neglect, contrasted the prevalence and severity of left-sided versus right-sided neglect, and determined the predictors of persistence versus recovery at follow up. Clinically, we found a double dissociation between ego- and allocentric neglect, with 50% of the neglect patients showing only egocentric neglect and 25% only allocentric neglect. Importantly, patients with only allocentric neglect did not demonstrate any egocentric spatial bias in the locations of the allocentric errors. Left-sided egocentric neglect was more prevalent and more severe than right-sided egocentric neglect, though right-sided neglect was still highly prevalent in the acute stroke sample (35%). Leftsided allocentric neglect was more severe but not more prevalent than right-sided allocentric neglect. Overall recovery of neglect was high: 81% of egocentric and 75% of allocentric neglect patients recovered. Severity of neglect was the only significant behavioural measure for predicting recovery at 6 months.