What is Posterior Cortical Atrophy (PCA)?

 PCA Syndrome: Early Signs, Alzheimer’s Connection & Care Tips

Posterior cortical atrophy (PCA) involves the slow and progressive deterioration of the cortex, which is the brain’s outer layer, specifically in the back region of the head. This region is responsible for interpreting visual input.

The disorder is commonly associated with an unusual form of Alzheimer's disease that mainly impacts the back portion of the brain. Less frequently, it may result from other disorders such as corticobasal degeneration, Creutzfeldt-Jakob disease or Lewy body dementia.

Therefore, it is essential to understand the symptoms of PCA and other details for early diagnosis and proper treatment. Keep reading to learn the PCA and other relevant details of this syndrome.

What are the symptoms of posterior cortical atrophy (PCA)?

PCA often begins to show symptoms in individuals between 50 and 60 years old. The condition impacts the posterior cerebral cortex, which includes the parietal and occipital lobes on the right and left sides of the brain.

These areas process visual information received from the eyes, allowing individuals to interpret and recognise what they see. In PCA, the brain cells in this area gradually degenerate and atrophy, causing problems with interpreting visual information. Common symptoms include:

• Difficulty reading, often losing track of text as lines appear to shift or words and letters seem jumbled; some report that words seem to slide off the page.
• Difficulty in judging distances, like gauging the gap between steps on a staircase or the space between a vehicle and the kerb; escalators can be particularly confusing because of hesitation about when to step on.
• Frequently bumping into furniture, doorways, or other objects due to impaired depth perception, even when these objects are directly in view.
• Trouble following directions correctly due to problems differentiating between left and right.
• Challenges with numbers, such as being unable to locate phone keypad numbers despite knowing a phone number.
• Trouble recognising familiar faces, objects, or locations.
• Difficulty operating tools and appliances because switches or controls are not perceived where they physically exist.
• Anxiety, which often emerges early and may be linked to disruptions in brain networks responsible for processing sensory, emotional, and cognitive information.

How is Posterior Cortical Atrophy (PCA) Diagnosed?

Several tests may assist in diagnosing the condition and ruling out other disorders with similar symptoms. These tests may include:

• Single-Photon Emission Computerised Tomography (SPECT) or Fluorodeoxyglucose (FDG) PET (Positron Emission Tomography) Imaging :  A tiny dose of radioactive tracer is introduced into a vein, and images are captured with advanced imaging equipment. The individual rests on a cushioned table that slides into a scanner shaped like a large circular opening. SPECT scans assess blood flow within the brain, while PET scans visualise brain activity.
• Magnetic Resonance Imaging (MRI) : This imaging technique employs powerful radio waves and magnetic fields to generate detailed 3D images of the brain, allowing healthcareproviders to identify any brain changes linked to the symptoms.
• Spinal Fluid Analysis : A small sample of cerebrospinal fluid, which surrounds the brain and spinal cord, is collected to measure amyloid and tau protein levels, which are key indicators of Alzheimer’s disease.
• Mental Status and Neuropsychological Evaluations : Questions and assessments are used to evaluate cognitive abilities, with additional screenings for depression or other mental health conditions.
• Blood Tests : Blood samples may be analysed to check for vitamin deficiencies, thyroid issues, or other underlying causes of the symptoms.
• Ophthalmology Examination : Vision tests determine if eye-related problems are contributing to visual symptoms.

How is Posterior Cortical Atrophy (PCA) Related to Alzheimer’s Disease?

Research suggests that posterior cortical atrophy may be a form of Alzheimer's disease, as both disorders often begin with visual impairments. Both conditions involve progressive neurodegeneration, affecting overlapping regions of the brain, resulting in synaptic loss, neurone death, and eventually dementia.

In Alzheimer’s disease, the hippocampus and prefrontal cortex are primarily affected. In contrast, PCA leads to degeneration in the posterior brain regions, later including the frontal, temporal, and occipital lobes, with noticeable loss of grey matter or neuronal cell bodies.

While Alzheimer’s disease predominantly disrupts episodic memory, PCA more significantly affects anterograde and working memory, generally sparing episodic memory in the earlier stages. Over time, the atrophy seen in PCA may extend to brain areas commonly affected by Alzheimer’s disease, leading to combined cognitive, memory, learning, and language difficulties.

Nevertheless, due to the complexity of its symptoms and frequent misdiagnosis, PCA often goes unrecognised. Ongoing research continues to focus on establishing standardised diagnostic criteria for more accurate identification of posterior cortical atrophy.

Early detection and proper diagnosis of posterior cortical atrophy (PCA) allow individuals to begin appropriate care, manage symptoms effectively, and maintain a better quality of life. With timely medical attention and ongoing support, many challenges related to PCA can be addressed proactively.

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