Summary: A straightforward, sensitive memory test can help predict which people without current cognitive symptoms will develop memory problems and cognitive impairment years later, according to new research.
Source: AAN
A simple memory assessment can identify elevated risk of future cognitive impairment in people who appear cognitively normal.
“There is growing evidence that some individuals who appear cognitively normal may already show very subtle signs of early impairment,” said study author Ellen Grober, PhD, of Albert Einstein College of Medicine in the Bronx, New York. “In our work, a brief, sensitive memory test predicted the likelihood of developing cognitive impairment among people who were otherwise considered to have normal thinking and memory.”
The longitudinal study tracked 969 adults with an average age of 69 who had no reported thinking or memory difficulties at enrollment. Each participant completed a short memory test and was followed for up to 10 years to observe who later developed cognitive impairment.
The memory assessment used in the study consists of two parts. During the study phase, participants view four cards; each card displays drawings of four common items. For each card, the participant is asked to identify the item that belongs to a given category—for example, naming “grapes” when prompted to indicate a “fruit.”
In the test phase, participants first try to freely recall the items they previously identified. This free-recall step measures retrieval ability. For any items not recalled spontaneously, participants are then given the category cue (for example, “fruit”), which tests memory storage and the ability to access a stored memory with help.
Based on performance, participants were classified into five stages—stages zero through four—using the Stages of Objective Memory Impairment (SOMI) framework. Stage zero denotes normal memory performance with no signs of impairment. Stages one and two reflect progressively greater difficulty with memory retrieval; these retrieval-focused stages may appear several years before dementia. In stages three and four, performance indicates impaired storage: participants are unable to recall all items even when given category cues. These latter stages are closer to the onset of dementia.
At baseline, 47% of participants were categorized as SOMI stage zero, 35% as stage one, 13% as stage two, and 5% were in stages three and four combined. Over the follow-up period, 234 participants developed cognitive impairment.
After accounting for age, sex, education and APOE4—a genetic variant known to influence Alzheimer’s disease risk—researchers found that people in SOMI stages one and two were about twice as likely to develop cognitive impairment compared with those at stage zero. Participants in stages three and four had approximately triple the risk of later cognitive impairment compared with stage zero.
The predictive value of the SOMI staging remained even after researchers adjusted for key Alzheimer’s disease biomarkers, including brain amyloid plaques and tau tangles. This suggests the memory test captures meaningful changes in cognitive function that relate to biological markers of neurodegeneration.
Based on the study’s follow-up estimates, roughly 72% of people in SOMI stages three and four were expected to develop cognitive impairment within 10 years, compared with about 57% in stage two, 35% in stage one and 21% in stage zero. These stage-based risks can help clinicians and researchers identify individuals at higher near-term risk for decline.
“Our findings support use of the SOMI system as a practical tool to identify people most likely to develop cognitive impairment,” Grober said. “Early detection has value for research—helping identify candidates for clinical studies—and for individuals, who can consult with their physicians about monitoring and interventions to support brain health.”
The study authors note limitations. The sample was largely white and well educated, which limits generalizability. Grober and colleagues call for additional research in larger, more diverse populations to confirm how well the SOMI system performs across different demographic groups.
Funding: The study was funded by the National Institutes of Health, the Alzheimer’s Association, Cure Alzheimer Fund and the Leonard and Sylvia Marx Foundation.
About this memory and cognition research news
Author: Natalie Conrad
Source: AAN
Contact: Natalie Conrad – AAN
Image: The image is in the public domain
Original Research: The findings will appear in Neurology