Orientation agnosia in pentagon copying

Pentagon copying is more impaired in dementia with Lewy bodies than in Alzheimer's disease.

OBJECTIVES In many cases the clinical differentiation of patients with dementia with Lewy bodies (DLB) from those with Alzheimer's disease (AD) has been difficult. Because many neuropsychological studies have reported greater visuospatial/constructional impairment in DLB than in AD, it was determined whether accuracy in copying the interlocking pentagons item on the mini mental state examinatio...

Object orientation agnosia: a failure to find the axis?

A dissociation between the ability to recognize misoriented objects and to determine their orientation has been reported in a small number of patients with vascular lesions. In this article, we describe a 57-year-old man with probable Alzheimer' s disease who shows the same dissociation. Neuroimaging findings indicated marked hypometabolism in the posterior cortical regions, particularly the po...

Agnosia for object orientation: naming and mental rotation evidence.

We have previously reported the performance of a patient (NL) who could recognize objects, but appeared to lack knowledge of their orientation. These results were interpreted as evidence that NL had isolated access to a viewpoint-independent (ventral stream) object recognition system. However, because NL's responses on naming tasks were not timed, it was not possible to establish whether he sho...

Supramodal agnosia for oblique mirror orientation in patients with periventricular leukomalacia

Preserved implicit form perception and orientation adaptation in visual form agnosia.

Visual form agnosia is mainly characterized by profound deficits in visual form and shape discrimination. Previous studies have shown that patients retain the capacity for coordinated motor behaviors, color naming and implicit letter perception. However, it is unknown to what extent other visual functions, such as implicit form and orientation perception, are preserved. To address these questio...