Posterior Cortical Atrophy

Posterior cortical atrophy (PCA), also referred to as Benson’s syndrome, is an uncommon, degenerative disorder of the nervous system and brain. Posterior cortical atrophy causes a deterioration of vision which includes problems with visual tasks such as judging distances and differentiating between objects that are moving or standing still. Quite often, the disorder will eventually cause problems with memory and other cognitive capabilities.

PCA is currently considered to be a specific form of dementia, but it may be a variation of Alzheimer’s disease. It causes the wasting away of the cerebral cortex (the outer layer of the brain at the back of the head) resulting in a progressive disruption of complex visual processing. Onset of the disorder occurs most frequently in older adults between the ages of 50 and 65.

Symptoms of Posterior Cortical Atrophy

Symptoms of posterior cortical atrophy can vary pretty significantly from one person to the next. They may also change as the disorder progresses. PCA produces progressive changes causing difficulties with visual tasks such as:

• Judging distances
• Reading a line of text
• Inability to perceive more than one object at a time
• Difficulties distinguishing between stationary and moving objects
• Frequent disorientation
• Problems identifying, maneuvering and using common objects

Other symptoms may also include:

• Hallucinations
• Trouble spelling simple words
• Difficulty performing mathematical calculations
• Increased anxiety and/or depression
• Reduced memory, typically in the later stages of the disorder

Brain or Physical Changes Associated with Posterior Cortical Atrophy

In posterior cortical atrophy, damage to the posterior cortex (the outer layer of the brain at the back of the head) causes a gradual and progressive deterioration of vision given that this is the area of the brain responsible for processing visual information. With posterior cortical atrophy, the posterior cortex frequently has plaques and tangles similar to those found in Alzheimer’s patients. At other times, however, the brain changes resemble other brain disorders such as dementia with Lewy bodies and a variant of Creutzfeldt-Jakob disease.

Causes/Risk Factors of Posterior Cortical Atrophy

Currently, the cause of posterior cortical atrophy is unknown. Although there are similarities to Alzheimer’s disease and other brain disorders such as dementia with Lewy bodies, it is unknown whether PCA has the same risk factors.

Diagnosis, Treatment and Care of Posterior Cortical Atrophy

Due to its rarity and unique presentation, initially, it’s not uncommon for a person with posterior cortical atrophy to be misdiagnosed. And, because it’s often first perceived as an “eye problem,” it’s also not uncommon for people with PCA to first seek treatment from an ophthalmologist who may not consider PCA to be the underlying cause.

Currently, there is no standard definition of posterior cortical atrophy and no standard diagnostic criteria, making it impossible to know how many people have the disorder. Some studies indicate approximately five percent of those diagnosed with Alzheimer’s also have PCA, but researchers believe the true percentage may be as high as 15%.

Healthcare professionals rely on a combination of the following to diagnose posterior cortical atrophy and to rule out other potential explanations for symptoms:

• Physical examination
• Blood tests
• Brain scans
• Neuropsychological tests
• Neurological examination

Knowing the characteristic features of PCA include a gradual onset of visual symptoms along with the preservation of memory and normal eye function, healthcare professionals often use this criterion to assist with the diagnosis. Another clue is the age of onset – between 50 to 65 years of age.

There are no known treatments to slow or halt its progression; although, its similarity to Alzheimer’s suggest that drugs used to treat Alzheimer’s may be helpful.