What causes Alzheimer’s? Not toxic amyloid, new study suggests | Sunday Observer

What causes Alzheimer’s? Not toxic amyloid, new study suggests

Alzheimer’s disease affects millions around the globe.

Yet, researchers are still at a loss as to why this condition - which is characterized by memory impairment and many other cognitive problems - occurs in the first place. And until they fully understand the cause, investigators will remain unable to devise a cure.

So far, the prevailing hypothesis among experts has been that the excessive accumulation of a potentially toxic protein - beta-amyloid - in the brain causes Alzheimer’s.

Researchers have argued that beta-amyloid plaques disrupt the communication between brain cells, potentially leading to cognitive function problems.

Now, a new study from the University of California San Diego School of Medicine and the Veterans Affairs San Diego Healthcare System suggests that while the buildup of beta-amyloid has associations with Alzheimer’s, it may not actually cause the condition.

In a study paper that appears in the journal Neurology, the researchers explain what led them to reach this conclusion.

“The scientific community has long thought that amyloid drives the neurodegeneration and cognitive impairment associated with Alzheimer’s disease,” says senior author Prof. Mark Bondi.

He notes that “[t]hese findings, in addition to other work in our lab, suggest that this is likely not the case for everyone and that sensitive neuropsychological measurement strategies capture subtle cognitive changes much earlier in the disease process than previously thought possible.”

In their study, the researchers worked with a total of 747 participants with different levels of cognitive health. All of the study participants agreed to undergo neuropsychological assessments, as well as PET and MRI brain scans.

Of the participants, 305 were cognitively healthy, 289 had mild cognitive impairment, and 153 displayed markers of what the investigators call “objectively-defined subtle cognitive difficulties (Obj-SCD).”