Integrative agnosia is a sub-disease of agnosia, meaning the lack of integrating perceptual wholes within knowledge. Integrative agnosia can be assessed by several experimental tests such as the Efron shape test, which determines the specificity of the disease being Integrative. This disease is often caused by brain trauma, producing medial ventral lesions to the extrastriate cortex. Affecting this region of the brain produces learning impairments: the inability to integrate parts such as spatial distances or producing visual images from short or long-term memory.
Symptoms and signs
Symptoms generally include memory or learning impairments, with the inability to integrate parts coherently. There is a big range to the severity of this disease and often the symptoms that are shown in each patient vary as well. As ambiguous as the general symptoms may be, patients are often treated of their respective symptoms as they appear and how critical the conditions are.
Causes
Some of the causes of integrative agnosia include stroke, traumatic brain injury, Alzheimer's disease, an anoxic episode following myocardial infarction, and progressive multifocal leukoencephalopathy.
Diagnosis
Cases with integrative agnosia appear to have medial ventral lesions in the extrastriate cortex. Those who have integrative agnosia are better able to identify inanimate than animate items, which indicates processes that lead to accurate perceptual organization of visual information can be impaired. This is attributed to the importance of perceptual updating of stored visual knowledge, which is particularly important for classes of stimuli that have many perceptual neighbors and/or stimuli for which perceptual features are central to their stored representations. Patients also show a tendency to process visual stimuli initially at a global rather than local level. Although the grouping of local elements into perceptual wholes can be impaired, patients can remain sensitive to holistic visual representations.
When determining whether a patient has form agnosia or integrative agnosia, an Efron shape test can be performed. A poor score on the Efron shape test will indicate form agnosia, as opposed to integrative agnosia. A good score on the Efron shape test, but a poor score on a figure-ground segmentation test and an overlapping figures test will indicate integrative agnosia. A patient with integrative agnosia will find it hard to group and segment shapes, especially if there are overlapping animate items or they can over segment objects with high internal detail. However, the patient should have and understand basic coding of shape.
Treatment
One treatment thought to be effective is the repeated exposure to a particular face or object, where impaired perception may be reorganized in memory, leading to improvement on tests of imagery relative to tests of perception. The key factor for this type of treatment to be successful is a regular and consistent exposure, which will lead to improvements in the long run. Results may not be seen right away, but are eventually possible.