Early memory problems linked to risk of Alzheimer's disease

A recent study published in the journal Neurology recruited older adults without noticeable cognitive impairment but who were concerned about their memory.

The researchers looked for links between memory loss and signs of Alzheimer's disease (AD). They found that people who self-reported memory problems were more likely to have elevated levels of proteins associated with Alzheimer's disease.

If further research confirms these findings, it could help doctors identify the disease early, allowing for earlier treatment.

Assessing Cognitive Abilities with Memory and Thinking Tests

A team of researchers from Harvard Medical School recruited 675 older adults with an average age of 72.

The participants first took cognitive tests that showed they had no cognitive impairment.

Each participant had a partner - a child, spouse, or friend - and 65% of them lived with the participant.

The participants answered questions about their memory and thinking skills, as well as how well they cope with everyday tasks. Their partners also answered the same questions about the participants.

The questions included:

“Compared to a year ago, do you feel that your memory has gotten significantly worse?” “Compared to a year ago, do you have more difficulty managing money?” Brain scans reveal early signs of Alzheimer’s Each participant underwent a brain scan to look for protein markers of Alzheimer’s called amyloid plaques and tau tangles.

While the exact mechanisms that lead to Alzheimer’s are still being investigated, two telltale signs are associated with its progression:

Amyloid plaques are a buildup of protein between neurons. Tau tangles are a buildup of protein inside neurons. Both of these processes limit the ability of cells to signal each other. This eventually leads to cell death. Over time, as more cells die, cognitive abilities decline and the brain can actually shrink, or atrophy.

Verna Porter, MD, a board-certified neurologist and director of dementia, Alzheimer's, and neurocognitive disorders at the Pacific Neuroscience Institute in Santa Monica, California.

Porter, who was not involved in the study, said the proteins "interfere with memory formation at both a biochemical and structural level by disrupting the physical integrity of neural networks. The memory impairments we see are related to changes in brain structure and function."

In the current study, 60% of participants had elevated levels of amyloid in their brains. People with higher amyloid levels are also more likely to have higher tau levels.

Memory Problems and Protein Buildup in Alzheimer's Disease

Brain scans showed that people who self-reported memory problems had higher levels of tau nodules. This association was even stronger in people with higher amyloid levels.

In other words, people who experience memory problems are more likely to have neurological signs of Alzheimer's disease, despite being cognitively healthy.

Lead author of the study, Rebecca E. Amarillo, PhD, said:

“Even though the participants had no cognitive impairment and were functioning normally in their daily lives, their partners were still able to notice subtle changes that had occurred over the year that were associated with biomarkers of Alzheimer's.”

“Our study included a high percentage of people with elevated amyloid levels, and so we were also able to see that memory complaints were associated with higher levels of tau nodules,” Amarillo explained in a press release.

“Our results suggest that asking questions about subjective cognitive decline in older adults with elevated biomarkers of Alzheimer's disease may be valuable for early detection of the disease,” she continued. “This is especially important because treatment given at the earliest detectable stage of the disease is expected to be most effective in slowing its progression.”

Amarillo said they plan to continue this study with longitudinal data to understand how this relationship works over time.

What signs of Alzheimer's disease should you look out for?

Porter spoke about the early signs of Alzheimer's disease that you should pay attention to. She explained that people should seek medical help and have a memory assessment done by a specialist if they or their loved ones notice that someone:

• constantly asks the same question;
• forgets a word, phrase or idea during a conversation;
• inserts the wrong word into a conversation, for example, saying “chair” instead of “sofa”;
• spends more time on daily tasks, such as paying bills or sorting mail;
• often loses objects or belongings at home;
• gets lost when walking or driving in a relatively familiar area;
• experiences sudden or unexplained changes in mood, personality, or behavior without an obvious cause.

Can dementia be prevented?

Although gradual decline in cognitive abilities is often part of normal aging, Alzheimer's disease and other types of dementia are not.

Although we cannot control some risk factors, such as our genetics and aging, some risk factors for dementia can be changed.

Iris Blotenberg, PhD, postdoctoral fellow at the German Center for Neurodegenerative Diseases, who was not involved in the recent study, explained that modifiable risk factors are “associated with at least one-third of dementia cases.” These factors include:

• lack of physical activity;
• smoking;
• excessive alcohol consumption;
• diabetes.

Blotenberg also said other health conditions can increase the risk of developing dementia, such as "stroke, heart attack, high blood pressure and obesity."

Because these conditions are more likely to occur in people who are sedentary, smoke, and drink alcohol frequently, addressing these problems can significantly reduce a person's risk of developing dementia.

Blotenberg added that hearing loss is a risk factor for dementia because “stimulation is so important for our brains to maintain cognitive function. Therefore, it is highly recommended to use a hearing aid if you or those around you notice hearing loss.”

Finally, social isolation—increasingly common in Western societies—increases the risk of dementia.

“For us as social creatures, social interaction is incredibly important and is ultimately an important form of stimulation for our brains,” Blotenberg said.

Geir Selbeck, professor at the Department of Geriatric Medicine at the University of Oslo in Norway, in addition to the above-mentioned risk factors, suggested that people avoid head injuries and areas with high levels of air pollution.

Selbeck, who was not involved in the recent study, explained that stress may also be a risk factor. Therefore, finding ways to minimize or cope with daily stress can be helpful.

“In general, it's good to start early and maintain a healthy lifestyle, but it's never too late to start,” Blotenberg said.

“It's always good to stay cognitively active—stimulation is critical for our brains. So, to the best of your ability, stay cognitively, socially and physically active, but be careful not to overexert yourself,” she concluded.