Researchers have revealed how a simple test in people without thinking or memory problems can predict the risk of developing cognitive impairment years later.
Ellen Grober, PhD, of the Albert Einstein College of Medicine in the Bronx, New York says “There is increasing evidence that some people without problems with thinking and memory 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 normal.”
The study included 969 people with an average age of 69 who had no problems with thinking or memory at the start of the study. They performed a simple memory test and were followed for up to ten years.
The test is divided into two phases. For the study phase, people are shown four cards, each with four drawings. They are asked to identify an item that belongs to a certain category. After being asked to identify “fruit”, participants can name the item “grapes”.
Participants are first asked to recall the items for the test phase. This assesses their ability to locate information. They are then assigned categories for items they do not remember. This phase assesses the memory storage.
The risk of developing cognitive impairment in people
Participants were divided into five groups, or stages zero to four, based on their test scores, within the Stages of Objective Memory Impairment (SOMI) system. Phase zero does not represent any memory problems. Stages one and two reflect increasing difficulty in retrieving memories, which can precede dementia by five to eight years.
These participants will still be able to remember the items when given cues. In the third and fourth stages, people cannot recall all the items even after being given cues. These stages precede dementia by one to three years.
A total of 47% of participants were in phase zero, 35% in phase one, 13% in phase two, and 5% in phase three and four combined. Of the participants, 234 people developed cognitive impairment.
After adjusting for age, gender, education and the gene that affects Alzheimer’s risk, APOE4, the researchers found that compared to people who were in SOMI stage zero, people in stages one and two were twice as likely to develop cognitive impairment. People who were in stages three and four were three times more likely to develop cognitive impairment.
After adjusting for Alzheimer’s disease biomarkers including brain amyloid plaques and tau tangles, SOMI continued to predict an increased risk of cognitive impairment.
The researchers estimated that after 10 years, about 72% of those in stages three and four would develop cognitive impairment, compared with about 57% in stage two, 35% in stage one, and 21% in stage zero.
“Our results support the use of the SOMI system to identify people most likely to develop cognitive impairment,” said Grober. “Detecting cognitive impairment in its earliest stages is beneficial for researchers investigating treatments. It could also benefit people found to be at increased risk by consulting their physician and implementing interventions to promote healthy brain aging.”
A limitation of the study was that the majority of participants were white and well educated. Grober said more research is needed in larger and more diverse populations.
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