Not Just Language: Persisting Lateralized Visuospatial Impairment after Left Hemisphere Stroke.

Abstract

Imbalances in spatial attention are most often associated with right hemisphere brain injury. This report assessed 25 chronic left hemisphere stroke patients for attentional bias. Participants were evaluated with a computerized visual search task and a standardized neuropsychological assessment known as the Behavioral Inattention Test (BITC). Twenty age-matched controls were also tested. Although little to no attentional impairment was observed on the BITC, the computerized visual search task revealed statistically significant contralesional attentional impairment in the left hemisphere stroke group. Specifically, these participants required 208 ms more viewing time, on average, to reliably detect visual targets on the right side of the display compared to detection on the left side, while controls showed a difference of only 8 ms between the two sides. The observation of significant leftward visuospatial bias in this chronic stroke group provides further evidence that the left hemisphere also plays a role in the balance of visual attention across space. These results have implications for left hemisphere patients who are often not screened for visuospatial problems, as well as for theories of visual attention which have primarily emphasized the role of the right hemisphere. (JINS, 2016, 22, 695-704).