Disorders of visual recognition

This chapter aims to illustrate how agnosia fits into the scheme of cortical visual processing which was previously discussed in the second chapter of this book. It begins by presenting different forms of visual agnosia. Two broad forms of visual object agnosia by Lissauer are presented: apperceptive agnosia and associative agnosia. The visual form of agnosia is then examined by focusing on its pathology as well as its symptomatology. A section of this chapter also gives emphasis to the most extensively tested patient with visual form agnosia, namely, patient D.F., and traces her history by looking at her visual perception deficits and visuomotor abilities. The latter part of this chapter provides two different sections on apperceptive agnosia and associative agnosia, including its effects on the left and right hemisphere of the brain.