Altitudinal neglect.

Previous clinical observations on patients with hemispatial neglect from unilateral hemispheric lesions suggest the brain's attentional mechanisms are organized along the horizontal dimensions of extrapersonal space. We now report a patient with Balint's syndrome caused by bilateral parieto-occipital infarctions, who demonstrated altitudinal neglect. On visual and tactile bisection of vertical rods, the patient consistently placed her mark well above the true midpoint, and this performance remained unchanged when the stimuli were simultaneously explored visually and tactually. She also showed altitudinal inattention in the visual modality by extinguishing the stimulus presented in the lower quadrants during double simultaneous stimulation across the horizontal meridian. These findings suggest that bilateral damage to the parietal lobes can lead to multimodal attentional and exploratory deficits along the vertical dimensions of extrapersonal space.