Having confusion or difficulties remembering recent events, where we left a certain object, or the name of an acquaintance, can indicate cognitive deterioration, and even be the first signs of the development of some type of dementia. Now, however, an international group of scientists led by the University of California, San Francisco (UCSF) has identified a set of visuospatial symptoms that would be the first signs of Alzheimer’s and can predict the future development of the disease and that manifest themselves in up to 10% of cases.
This is the first large-scale study of posterior cortical atrophy (PCA) and included data from more than 1,000 patients from 36 sites in 16 countries. Researchers have proven that posterior cortical atrophy significantly predicts Alzheimer’s disease, since around 94% of patients with PCA had Alzheimer’s pathology and the remaining 6% suffered from conditions such as dementia with Lewy bodies and brain degeneration. frontotemporal lobe. On the contrary, other studies show that 70% of patients with memory loss have Alzheimer’s disease.
Most patients with ACP have normal cognition from the beginning, but by the time of their first diagnostic visit, an average of 3.8 years after the onset of symptoms, mild or moderate dementia was evident and deficits in memory, executive function, behavior, and speech and language, according to the researchers’ findings, which have been published in Lancet Neurology.
Symptoms of posterior cortical atrophy that precede Alzheimer’s
Unlike common memory problems, people with PCA have difficulty calculating distances, distinguishing between moving and stationary objects, and completing tasks such as writing and retrieving a dropped object despite normal eye exam results. , explained Marianne Chapleau of the UCSF Department of Neurology, the Center for Memory and Aging and the Weill Institute for Neurosciences, and co-author of the work.
At diagnosis, 61% demonstrated “constructional dyspraxia,” an inability to copy or construct basic diagrams or figures; 49% had a “spatial perception deficit,” difficulties identifying the location of something they saw; and 48% had “simultanagnosia,” a disorder characterized by the inability to visually perceive more than one object at a time or to unify independent details into a single coherent scene. In addition, 47% had difficulties performing basic mathematical calculations and 43% had difficulties with reading.
The average age of onset of ACP symptoms is 59 years, several years younger than when the characteristic memory symptoms of Alzheimer’s appear.
“We need more awareness about ACP so that doctors can detect it,” said Chapleau. “Most patients go to their optometrist when they start experiencing visual symptoms and may be referred to an ophthalmologist, who may also not recognize ACP,” he said. “We need better tools in clinical settings to identify these patients early and provide them with treatment.”
The average age of onset of ACP symptoms is 59, several years younger than when Alzheimer’s characteristic memory symptoms appear, and this is another reason why ACP patients are less likely to be diagnosed, Chapleau added. . Early identification of ACP may have important implications in the treatment of Alzheimer’s, says co-author Renaud La Joie, also of the Department of Neurology and the UCSF Memory and Aging Center.
In the study, amyloid and tau levels identified in cerebrospinal fluid and imaging, as well as autopsy data, matched those found in typical Alzheimer’s cases. As a result, patients with ACP may be candidates for anti-amyloid therapies, such as lecanemab (Leqembi), approved by the US Food and Drug Administration in January 2023, and anti-tau therapies, currently in clinical trials, and It is believed that both would be more effective in the early stages of the disease, he concludes.
