Researchers have uncovered a significant link between subtle changes in everyday memory, attention, and navigation abilities and biological markers of Alzheimer’s disease. This finding, published in the Journal of the International Neuropsychological Society, suggests that simple self-reported and informant-reported assessments could serve as early indicators of Alzheimer’s.
Alzheimer’s disease is a progressive neurological condition predominantly seen in older adults. It is characterized by a gradual decline in cognitive abilities, including memory, reasoning, and communication skills. This decline is caused by the degeneration and death of brain cells, leading to a decrease in brain size and function over time. Alzheimer’s disease is the most common cause of dementia, a broad term for conditions that negatively affect mental capabilities severely enough to interfere with daily life.
Previous research in the field of Alzheimer’s disease has primarily focused on identifying the disease after symptoms have become apparent. However, by the time symptoms are noticeable, significant brain damage has already occurred, making treatment and management more challenging. This has led scientists to explore ways to detect Alzheimer’s earlier, potentially even before symptoms are noticeable. A key area of interest has been identifying subtle cognitive changes that may occur in the preclinical stages of the disease, which could serve as early warning signs.
“The pandemic and subsequent shift toward virtual healthcare highlighted the need for cognitive assessments that could be conducted remotely. This led to my interest in examining subjective changes in memory and thinking ability using questionnaires,” said study author Taylor F. Levine, a postdoctoral fellow at Cleveland Clinic Lou Ruvo Center for Brain Health, who completed the research while a graduate student at Washington University in St. Louis.
The study utilized data from the Alzheimer’s Disease Neuroimaging Initiative, focusing on 320 participants who were clinically normal at the outset. These participants, along with their informants (people who know them well, such as family members), completed the Everyday Cognition (ECog) scale — an assessment designed to gauge changes in everyday cognitive functions. Additionally, biological markers linked to Alzheimer’s disease, specifically proteins in cerebrospinal fluid and hippocampal volume (a brain area crucial in memory formation), were measured.
There was a noticeable decline over time in both self-reported and informant-reported cognitive abilities. Interestingly, informant-reported declines in cognitive abilities were generally steeper than self-reported changes. This implies that informants might be more attuned to or able to detect subtle changes in cognitive abilities than the individuals themselves, especially in the preclinical stages of Alzheimer’s Disease.
The researchers found that declines in self-reported and informant-reported memory, attention, and spatial navigation abilities over time could be predicted by certain brain changes and biomarker levels. Specifically, a higher ratio of certain proteins in the cerebrospinal fluid and smaller hippocampal volumes were associated with these declines. This suggests that changes in these biological markers are closely linked to the subtle cognitive changes that the participants or their informants reported.
The findings indicate that “tracking subjective changes in memory and thinking ability may be useful for the individual and/or their treating providers to monitor for brain changes related to Alzheimer’s disease,” Levine told PsyPost.
However, there were some limitations to the study. The participants were predominantly Non-Hispanic White, which raises questions about the applicability of these findings across different racial and ethnic groups. Also, the data used in the study was pre-collected, meaning the researchers could not control when the cognitive assessments or biological samples were taken relative to each other. This factor could have influenced the results, although the researchers made considerable efforts to mitigate its impact.
“I was interested in examining subjective cognitive change in the earliest stages of Alzheimer’s disease, before individuals have dementia symptoms,” Levine said. “The questionnaire used for this study was not originally developed for early-stage Alzheimer’s disease. Questionnaires developed specifically for early-stage Alzheimer’s disease may provide more/better information than the one used in this study.”
Looking ahead, this study opens several avenues for future research. Comparing the effectiveness of the Everyday Cognition scale with other cognitive assessment tools could further refine the detection of Alzheimer’s in its early stages. Additionally, exploring the use of these methods in a more diverse population would help in understanding the applicability of these findings across different groups.
The study, “Alzheimer disease biomarkers are associated with decline in subjective memory, attention, and spatial navigation ability in clinically normal adults“, was authored by Taylor F. Levine, Steven J. Dessenberger, Samantha L. Allison, Denise Head, and the Alzheimer’s Disease Neuroimaging Initiative.