Early memory problems linked to risk of Alzheimer's disease

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

Scientists were looking 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 detect the disease early, allowing treatment to begin sooner.

Assessing cognitive abilities using memory and thinking tests

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

Participants first took cognitive tests, which showed that they had no cognitive impairment.

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

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

Questions included:

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

Although the exact mechanisms leading to Alzheimer's disease are still being investigated, two clear signs are associated with its progression:

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

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

Porter, who was not involved in the study, said the proteins "interfere with memory formation at both the biochemical and structural levels by disrupting the physical integrity of neural networks. The observed memory impairments are associated with 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 were also more likely to have higher levels of tau.

Memory Problems and Protein Buildup in Alzheimer's Disease

Brain scans showed that people who self-reported memory problems had higher levels of tau. The link 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, even though they are cognitively healthy.

Lead study author 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 occurred over the year that were associated with Alzheimer's biomarkers."

"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," Amarillo explained in a press release.

“Our results suggest that asking about subjective cognitive decline in older adults with elevated Alzheimer’s disease biomarkers may be valuable for early detection of the disease,” she continued. “This is especially important because treatment given at the earliest diagnosable 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 link works over time.

What are the signs of Alzheimer's disease to look out for?

Porter outlined the early signs of Alzheimer's disease to look out for. She explained that people should seek medical attention and have a memory assessment from a specialist if they or a loved one notices that someone:

• keeps asking the same question;
• forgets a word, phrase, or idea during a conversation;
• inserts the wrong word into a conversation, such as saying "chair" instead of "sofa";
• spends more time doing everyday tasks, such as paying bills or sorting through mail;
• often loses objects or things at home;
• gets lost when walking or driving in a relatively familiar area;
• experiences sudden or unexplained changes in mood, personality, or behavior for no apparent reason.

Can dementia be prevented?

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

While we can't influence some risk factors, such as our genetics and aging, some risk factors for dementia can be modified.

Iris Blottenberg, PhD, a 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 issues can significantly reduce a person's risk of developing dementia.

Blottenberg added that hearing loss is a risk factor for dementia because "stimulation is so important for our brains to maintain cognitive function. So it's highly recommended that you use a hearing aid if you or those around you notice a decrease in hearing."

Finally, social isolation – which is increasingly common in Western societies – increases the risk of dementia.

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

Geir Selbeck, a 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 can also be a risk factor, so finding ways to minimize or manage daily stress can be helpful.

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

“It’s always a good idea 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.