Abstract
Patients with landmark agnosia, a subtype of topographical disorientation,are specifically unable to recognize salient features of their environment, such as buildings and landscapes. Previous case reports suggested that these patients do not have perfectly intact visual perception, but there have been few detailed studies of the perceptual abilities of such patients. To investigate the mechanism underlying landmark agnosia, we examined the perceptual ability of FS, a 78-year-old female patient. Since suffering a cerebrovascular accident, the patient has exhibited landmark agnosic symptoms only in novel environments. Several subtests of the Visual Perception Test for Agnosia (VPTA) demonstrated preserved fundamental visual function and normal recognition for simply presented objects. However, FS also manifested marked deficits of visual perception in a series of tests that required large amounts of holistic processing. The patient could not integrate elements of stimuli and could not perceive their global configuration in complex visual conditions. When we construct largescale topographical representations, it is important to integrate partial information input successively as a whole. Therefore, FS's severe deficits of visual integration and configural processing demonstrated in holistic perception tests might be influencing the construction of representations of buildings and landscapes and, as a result, might be inducing to landmark agnosia.
