Influence of Spatial Neglect, Hemianopia and Hemispace on the Subjective Vertical

The perception of the vertical is frequently shifted to the contralesional side in patients with hemispheric lesions, and this is amplified by spatial neglect. However, we do not know the specific influence of hemianopia and space of perception on this phenomenon. Here, we analyzed the respective influences of spatial neglect, hemianopia and hemispace on the subjective vertical in patients with right hemispheric stroke. Twelve neglect patients with and 5 without hemianopia were compared to 3 non-neglect patients with and 13 without hemianopia. They had to match a luminous rod to the vertical, either in the mid-sagittal plane or in the right or the left hemispace. Patients showed a counter-clockwise deviation, and this was exaggerated by both neglect and hemianopia. In patients with neglect, the error was greater in the left hemispace. In conclusion, neglect and hemianopia had additive effects on the contralesional bias of the subjective vertical.