A Better Test to Predict Alzheimer’s?

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John Livzey

Among the many difficult features of Alzheimer’s is that doctors can never really say with certainty which patients who show signs of memory loss will go on to develop the neurodegenerative disorder.

That’s because not all people who show lapses in memory necessarily have Alzheimer’s. Even people who have higher levels of the brain-clogging protein amyloid, the hallmark of the disease, don’t necessarily develop it.

But in the latest study on screening patients for early biomarkers of Alzheimer’s, an international group of scientists reports that a combination of tests could predict with about 80% those who will develop the disease.

The researchers focused on 58 patients with mild cognitive impairment (MCI), a condition that includes memory lapses and periods of confusion that are more severe than the normal senior moments that come with aging, but not severe enough to qualify as dementia. About 15% of patients who have MCI go on to develop Alzheimer’s. The question is, which ones?

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When the team looked at the levels of an early form of amyloid in the spinal fluid of participants, they found that MCI patients with higher levels of the protein’s precursor were more likely to get Alzheimer’s three years later. Doctors currently test for a later form of amyloid protein, which may help them distinguish Alzheimer’s from other possible causes of memory loss, but which the authors believe may appear too late in the disease process to be of use in predicting which patients will transition from MCI to Alzheimer’s.

When the scientists combined the reading of amyloid precursor in the spinal fluid with tests for another protein called tau, which is made when nerve cells start to break down, along with the patient’s age, they were able to predict with 80% accuracy which patients with MCI would experience a decline in their condition toward Alzheimer’s.

“We might have found something that could really provide significant health benefit for patients from a medical and not just research perspective,” says co-author Robert Perneczky, in the department of psychiatry and psychotherapy at the Technical University of Munich.

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Before doctors can start using the test, however, the findings will have to be confirmed in other populations of MCI patients. If they are validated, the screen might prove useful in helping those who are at higher risk of developing Alzheimer’s to begin interventions that may delay progress of the disease. Although there aren’t any effective treatments yet, studies have shown that keeping socially and physically active can slow down the cognitive decline that occurs once amyloid starts to interfere with normal nerve function in the brain.

The study was published online in the journal Neurology.