Posterior cortical atrophy (PCA) can manifest as visual disturbances that are often mistaken for mere eye problems, obscuring the underlying neurological issue. This condition, characterized by the deterioration of brain tissue responsible for visual interpretation, may precede the onset of memory deficits, as indicated by a recent study.
Alzheimer’s disease, notorious for its association with memory loss, can manifest differently, particularly in its early stages. Research indicates that alterations in visual perception, particularly among women, may precede cognitive decline, shedding light on a lesser-known aspect of the disease.
In an effort to elucidate these findings, investigators analyzed data from nearly 1,100 individuals diagnosed with PCA, a condition linked to the degeneration of brain regions crucial for processing visual information. The repercussions of this degeneration extend to everyday tasks such as driving and reading, often presenting as challenges with depth perception and nocturnal reading.
Post-mortem examinations revealed that a staggering 94 percent of PCA cases were associated with Alzheimer’s disease, The Lancet Neurology journal underscores the strong correlation between the two conditions. This suggests that PCA primarily arises as a consequence of Alzheimer’s pathology.
Remarkably, PCA tends to manifest at an earlier age than traditional Alzheimer’s diagnoses, typically around 59 years old, with women constituting the majority of cases at 60 percent, as per the National Institutes of Health. Despite initially maintaining cognitive function, individuals with PCA often experience a delay in diagnosis, leading to the emergence of mild to moderate dementia over approximately four years. This progression is marked by deficits in memory, executive function, behavior, and speech.
Dr. Marianne Chapleau, the lead author of the study and a neuropsychologist at the University of California in San Francisco, emphasizes that many individuals may not recognize the significance of PCA as an early indicator of Alzheimer’s disease, highlighting the importance of awareness and timely intervention in detecting and managing this condition.
“Visual symptoms in PCA may precede noticeable and broader cognitive issues associated with Alzheimer’s, because individuals often attribute visual problems to aging eyesight rather than connecting them to dementia,” Dr. Chapleau said. Because of such, they get to miss out on the chance to seek intervention much earlier.
Problems with Visual Perception
The study revealed that a significant majority, 61 percent, of participants exhibited a condition termed “constructional dyspraxia” upon being diagnosed with posterior cortical atrophy (PCA). This condition manifested as an inability to accurately replicate simple diagrams or figures. Furthermore, nearly half of these individuals encountered difficulties in spatial perception, struggling to identify the locations of objects they observed and grappling with perceiving multiple objects simultaneously.
Andrew Budson, MD, who serves as the chief of cognitive behavioral neurology at VA Boston and holds a position as a neurology professor at Boston University, as well as being a coauthor of “Six Steps to Managing Alzheimer’s Disease and Dementia,” underscores that these symptoms might not immediately prompt one to consider Alzheimer’s disease.
“They usually begin by going to their optometrist to get their eyeglasses prescription adjusted, then they might go to the ophthalmologist when the optometrist cannot help them,” said Dr. Budson. He wasn’t part of the new study. “Only then will the ophthalmologist realize that the problem is likely in the brain and not related to the eyes and refer the patient to a neurologist.”
However, according to Budson, even the initial neurology consultation may not necessarily result in a PCA diagnosis. Individuals might still require a magnetic resonance imaging (MRI) scan indicating brain shrinkage patterns coherent with PCA, followed by a consultation with a specialist in dementia or memory disorders.
Benefits of Getting Diagnosis Early
Securing a timely PCA (Posterior Cortical Atrophy) diagnosis is of utmost importance due to the potential for implementing effective symptom management strategies, according to Budson. Given that PCA is commonly associated with Alzheimer’s disease, the utilization of anti-amyloid medications such as lecanemab (Leqembi) could potentially impede the progression of symptoms.
Budson emphasizes the need for further research to enhance our understanding of PCA, expressing optimism that, in the future, it may be feasible to identify the condition at its nascent stages. This could open avenues for employing Alzheimer’s drugs to prevent its exacerbation.
Although there is currently no specific method to prevent PCA or cure the condition, lifestyle modifications can still yield positive outcomes, as highlighted by Chapleau. Therefore, early diagnosis, coupled with pharmaceutical interventions and lifestyle adjustments, holds promise in managing and potentially mitigating the impact of PCA.
“Adopting a healthy lifestyle with regular exercise, a balanced diet, and cognitive activities may contribute to overall brain health,” Chapleau said. “Once diagnosed, managing symptoms and slowing the progression of dementia can be supported through interventions like cognitive therapies, medications, and individualized care plans.”
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