Memory loss may not be the first warning sign of Alzheimer’s disease. This change appeared months earlier

A new study has identified a potential warning sign of Alzheimer’s disease that can appear months before memory-related changes.

The study, published in the peer-reviewed journal Natural communicationsfound that animal models with Alzheimer’s-related brain changes developed problems with cognitive flexibility months before showing signs of memory problems.

Cognitive flexibility is the ability to change course when situations change. Jun Wang, a professor at Texas A&M University’s Naresh K. Vashisht College of Medicine at Texas A&M Health, told Inc. that this skill helps people switch tasks, adjust plans and set aside old habits when new approaches are needed.

“In everyday life, someone may manage a familiar routine well but have difficulty when priorities change,” Wang told Inc. “They may continue to use a strategy that no longer works or have difficulty rearranging a multi-step task after an unexpected problem.”

The findings suggest that by the time memory problems become visible, damage associated with the disease may already be underway.

The first changes observed by researchers before memory problems

For the study, researchers engineered mice to develop Alzheimer’s-like accumulation of amyloid. They found that the brain circuit involved in planning and decision-making became overactive from the start. Signaling of acetylcholine, the brain chemical involved in flexible behavior, was reduced.

The team focused on measuring cognitive flexibility with a reversal learning test. In this test, the mice learned that a particular action leads to a reward. Once the association was created, the researchers changed the rules and rewarded a different action.