POSTERIOR CORTICAL ATROPHY

PCA; Benson’s Syndrome; Biparietal Alzheimer Disease; Primary Visual Agnosia; Visual Variant of Alzheimer’s Disease; VVAD

Posterior Cortical Atrophy (PCA) is a rare neurologic disease characterized by impairment of higher visual processing skills and other posterior cortical functions without any evidence of ocular abnormalities, relatively intact memory and language in the early stages. PCA causes atrophy of the posterior part of the cerebral cortex, resulting in the progressive disruption of complex visual processing. This rare form of dementia is considered a visual variant or an atypical variant of Alzheimer’s disease (AD).

Diagnostic testing: The cause of PCA is unknown, and there are no fully accepted diagnostic criteria for the disease. This is partially due to the gradual onset of PCA symptoms, their variety, the rare nature of the disease, and the younger age of onset.

The following may assist with diagnosis:

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  A history and physical exam;

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  Neuroimaging (MRI, CAT scan) showing atrophy affecting occipital, parietal, and posterior temporal lobes bilaterally, many with more severe change on the right; and

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  Careful observation in relation to PCA symptoms.

Physical findings: Individuals with PCA may present with:

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  Difficulty reading;

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  Blurred vision;

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  Light sensitivity;

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  Issues with depth perception;

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  Trouble navigating through space;

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  Apraxia (disorder of movement planning);

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  Alexia (impaired ability to read);

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  Visual hallucinations;

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  Dementia;

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  Anxiety; and

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  Depression.

ICD-9: 377.7

ICD-10: R48.3

PCA usually affects people at an earlier age than typical cases of Alzheimer's disease, with initial symptoms often experienced in people in their mid-50s or early 60s.

Specific and accepted treatment for PCA has yet to be discovered; this may be due to the rarity and variations of the disease. At times people with PCA are treated with AD treatments such as, cholinesterase inhibitors, donepezil, rivastigmine, galantamine, and memantine. Antidepressant drugs have also provided some positive effects.

Other treatments such as occupational therapy or help with adapting to visual changes may help.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation:

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  Clinical history and examination that describes the diagnostic features of the impairment; and

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  Neuroimaging.

Suggested Listings for Evaluation:

REMARKS