ABSTRACT
Agnosia was first described by H. Lissauer as a modality-specific disorder of visual recognition. Traditionally two simple clinical tests have been used to establish the integrity of apperceptive processes: shape discrimination and shape copying. A patient failing these tasks would be classified as suffering from apperceptive agnosia, while patients who succeeded would be classed as having associative agnosia. H. J. A. had impaired perceptual integration of shape elements into perceptual wholes, a disorder they termed integrative agnosia. Such patients may be distinguished from cases where shape discrimination and copying abilities are severely impaired, a disorder labelled as form agnosia. One of the problems inherent in reports of single cases of patients with visual agnosia is that there is little consistency in the diagnostic tests used. Lesion information is also available for patients with integrative agnosia. Cases here have been reported following stroke, traumatic brain injury, Alzheimer's disease and progressive multifocal leukoencephalopathy.
