An unexpected early symptom of Alzheimer's disease has been identified

Women at risk

Alzheimer's disease is usually viewed as a disease that destroys memory. However, for some people, vision problems may be an early sign of dementia. Symptoms may appear 5-6 years earlier than the more serious stage of Alzheimer's disease.

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Insidious Alzheimer's disease manifests itself as forgetfulness, difficulty remembering recent events, and confusion. Often the early symptoms of the disease are overlooked. However, scientists have concluded that some people may experience a lesser-known early sign of dementia in the form of vision problems (such as problems judging distances, distinguishing between moving and stationary objects, and writing).

These symptoms can go undiagnosed for years if a person only sees their eye doctor. That's because many doctors are simply unaware of the link between vision problems and dementia due to little research on the issue.

Doctors are aiming to change that with the first-ever large-scale international study of a phenomenon known as posterior vision. cortical atrophy (CCA), conducted by the University of California, San Francisco. It was published in the journal Lancet Neurology. For the study, the team reviewed the medical records of more than 1,000 patients with PCA from 16 different countries.

Patients begin to exhibit visual-spatial symptoms of the disease about five or six years earlier than those with the more common form of Alzheimer's disease.

Although the exact number of people with PCA is not known, researchers estimate that this variant may account for up to 10% of Alzheimer's disease cases, bringing the number of Americans with the disease close to 700,000.

PCA is a specific subtype of Alzheimer's disease, and not all patients with this form of dementia experience symptoms, which also include difficulties with reading, using everyday objects, judging distances and recognizing faces. Memory problems may become more apparent as the disease progresses.

The average age at which symptoms typically begin is 59, which is six years earlier than the average age when Alzheimer's disease is diagnosed.

Symptoms can occur in people who have no other memory problems, leading some to think the problems are not neurological. Deteriorating vision is a side effect of the general aging process, and many adults in their 50s and 60s are likely to attribute their vision problems to advanced age and instead of seeking medical help, begin to look for glasses. Time may be lost.

The average time required from the first appearance of atypical visual symptoms to diagnosis is just under four years.

Co-author of the paper and researcher from the Department of Neuroscience at the Center for Memory and Aging at the University of California, San Francisco, Marianne Chapleau, said: “We need more awareness of PCA so that doctors can notice it. Most patients see an eye doctor when they begin to have visual symptoms, and they may be referred to an ophthalmologist, who may also not recognize this early sign of dementia. We need better tools in clinical settings to identify these patients early and treat them.”

In the study, the researchers measured levels of two hallmarks of Alzheimer's disease—tau protein and amyloid protein. Beta amyloid accumulates in the brain, forming plaque deposits that are believed to cause inflammation in the body and lead to disruption of communication between brain cells.

Meanwhile, tau protein usually helps stabilize the internal structure of nerve cells in the brain. But in Alzheimer's disease, abnormal chemical changes cause tau to break away from nerve cells and reattach to other tau proteins, forming filaments that eventually become tangles.

People with PCA had the same level of tau and amyloid plaques in the brain, as do people with the more common form of Alzheimer's disease.

Better understanding of PCA «is critical to both improving patient care and understanding the processes that lead to Alzheimer's disease,» said Dr. Gil Rabinovich, director of the UCSF Alzheimer's Disease Research Center.

He added, “It is critical that physicians learn to recognize the syndrome so that patients can receive proper diagnosis, counseling, and care. From a scientific perspective, we really need to understand why Alzheimer's disease affects the visual and not the memory areas of the brain. Our study showed that 60% of patients with PCA were women. Better understanding why they seem more susceptible is an important area of ​​future research.»