Early detection and prediction of cognitive impairment can help improve patient outcomes and management of conditions like Alzheimer’s disease and other forms of dementia. If a simple test can predict cognitive impairment before symptoms appear, it has the potential to revolutionize diagnosis and intervention strategies.
According to a study published in the online issue of Neurology®, the medical journal of the American Academy of Neurology, a simple test in people with no thinking or memory problems may predict the risk of developing cognitive impairment years later.
“There is increasing evidence that some people with no thinking and memory problems may actually have very subtle signs of early cognitive impairment,” said study author Ellen Grober, PhD, of Albert Einstein College of Medicine in the Bronx, New York. “In our study, a sensitive and simple memory test predicted the risk of developing cognitive impairment in people who were otherwise considered to have normal cognition.”
There is increasing evidence that some people with no thinking and memory problems may actually have very subtle signs of early cognitive impairment. In our study, a sensitive and simple memory test predicted the risk of developing cognitive impairment in people who were otherwise considered to have normal cognition.
Ellen Grober
The study included 969 people with an average age of 69 who did not have any thinking or memory issues at the start of the study. They took a simple memory test and were monitored for up to ten years.
The test is divided into two phases. People are shown four cards, each with four drawings, for the study phase. They are asked to identify an item that belongs to a specific category. Participants, for example, might name the item “grapes” after being asked to identify a “fruit.” Participants are first asked to recall the items for the test phase. This assesses their ability to locate information. They are then given category cues for items they do not recall. This stage assesses memory storage.
As part of the Stages of Objective Memory Impairment (SOMI) system, the participants were divided into five groups, or stages zero through four, based on their test scores. There are no memory issues in stage zero. Stages one and two reflect increasing difficulty retrieving memories, which can occur five to eight years before dementia. When given cues, these participants continue to remember items. Even after being given cues, people in the third and fourth stages cannot remember all of the items. These stages occur one to three years before dementia.
A total of 47% of the participants were in stage zero, 35% in stage one, 13% in stage two and 5% in stages three and four combined.
Of the participants, 234 people developed cognitive impairment.
After controlling for age, gender, education, and APOE4, a gene that affects a person’s risk of Alzheimer’s disease, researchers discovered that people in SOMI stages one and two were twice as likely to develop cognitive impairment as people in SOMI stage zero. Individuals in stages three and four were three times more likely to develop cognitive impairment. After controlling for Alzheimer’s disease biomarkers such as brain amyloid plaques and tau tangles, the SOMI system continued to predict an increased risk of cognitive impairment.
Researchers estimated that after 10 years about 72% of those in the third and fourth stages would have developed cognitive impairment, compared to about 57% of those in the second stage, 35% in the first stage and 21% of those in stage zero.
“Our results support the use of the SOMI system to identify people who are most likely to develop cognitive impairment,” Grober said. “Detecting cognitive impairment in its early stages is advantageous for researchers looking into treatments. It could also help those who are found to be at higher risk by consulting with their doctor and implementing interventions to promote healthy brain aging.”
One study limitation was that the majority of participants were white and well educated. Grober believes that more research in larger and more diverse populations is required.
