[5] In these cases there may be a melodic or a memory basis established in the brain and damage to those areas lead to music agnosia.
Braille reading speed can be affected by this condition, being slowed down due to the reduced pace of processing tactile information.
[2] Following Hermann Munk's identification of a condition he called "Seelenblindheit" (mind-blindness) Heinrich Lissauer published an exhaustive diagnostic evaluation of a patient who could not, or only with great difficulty, visually identify common objects.
[citation needed] The topic became prominent when Kurt Goldstein and Adhėmar Gelb published performance details of a patient Schn.
[12] He was followed over many years and created a great deal of controversy when subsequent tests were found to be at variance with the original findings.
Impairments of elements such as color and motion makes it difficult to interpret shape or the spatial arrangements of objects.
In some cases individuals are able to trace letters and shapes with their finger but they are unable to use the technique as a strategy to name objects.
Specific deficits include impairments in the recognition of body parts, buildings, manipulated objects, animals, and places.
[9] Picture naming is impaired in visual apperceptive agnosia but recognition of objects can be achieved through accessing other modalities.
[16] The continuing of the ability of patients to recognize the object through use of different sensory modalities shows that deficits arise because of a breakdown in the interaction between visual systems and semantic memory.
However, brain damage in proximity to the occipital lobe is largely correlated with the patterns of deficit seen in apperceptive agnosics.
[2] For example, patient JB suffered extensive damage to the parietal-occipital areas to the left cerebral hemisphere leading to his deficit in the ability to name distinguish between structurally similar object.
Yet another theory suggests that the pattern of deficit arise from independent impairments to a particular input modality and a single non perceptual semantic system that is organized by category.
[citation needed] In this step the structural description is mapped onto the semantic representations giving rise to a full specification of the object.
Based on patient information it seems that objects belonging to a category with many structurally similar neighbours would be vulnerable to this semantic access impairment.
His abilities show evidence that the problem may lie in an interaction between processes involved in specification of the object's visual structural description and access to semantic systems.
In 1982, he was first admitted to a hospital for Atrial Fibrillation, and presented symptoms of left/ right confusion, nominal dysphasia, agraphia (minus the Alexia), and dysgraphia.
In addition, unlike many patients, the ability to identify overlapping drawings of man-made objects remained intact.
[citation needed] Visual agnosia (both apperceptive and associative) is prevalent in Alzheimer's disease (AD) patients.
There is early involvement in the hippocampus and the entorhinal cortex followed by a spread to adjacent areas with neurofibrillary tangles (NFT).
Gradual extension of NFT throughout the occipital, parietal, and temporal regions devoted to vision occur resulting in visual agnosia.