Have you ever wanted to tell a joke only to find out you forgot how it begins?
Researchers from Liverpool John Moores University (LJMU) and the University of Wisconsin, Madison, think that struggling to recall narratives might be a sign of dementia.
They say people who are more likely to forget the start of a story they previously knew demonstrate higher levels of a protein in the brain, called amyloid beta, which is a biomarker of Alzheimer’s disease.
“We knew that people forgetting the first things on a list were at heightened risk of dementia so we wanted to find out if it was the same for other types of memory,” explains Dr Davide Bruno, from the School of Psychology at LJMU.
“Not all memory is the same. Remembering a story may be easier than remembering items on a list because a story benefits from a coherent structure. And so we were not sure whether the order in which information was learned would still have an effect in memory when recalling a story. It turns out that it does.”
What they did
The team examined data from the Wisconsin Registry of Alzheimer’s Prevention in two stages. First, they studied memory performance in a sample of 653 people to see whether, as with lists, it was easier to remember the first part of the story compared to the middle of the story, which it was. In the second stage, they then they looked at a sub-sample of 223 individuals for whom they had longitudinal data. The goal of this analysis was whether risk of being classed as amyloid positive, in other words having evidence of amyloid plaques in the brain, was linked to how well they remembered the beginning of two stories that are part of a common neuropsychological test.
The authors performed a binary regression analysis controlling for known risk factors for Alzheimer’s disease, including whether they carried certain dangerous genetic variants, and found that while forgetting the story as a whole was not helpful in predicting final classification, forgetting the first third of the story was.
“Presence of amyloid plaques in the brain is hypothesised to kickstart neurodegeneration in Alzheimer’s disease,” added Dr Bruno.
“While we are not sure exactly why, forgetting what we learn at the beginning tells us that Alzheimer’s pathology may be settling in. We think it may be related to preserving information about the order of events – a fundamental feature of memory the loss of which is somewhat akin to a canary in a coalmine, so to speak.”
The researchers say the finding is important because having easy, inexpensive and accurate ways of identifying dementia in people who are otherwise asymptomatic, is the first step towards early interventions to prevent or delay the disease.
While there is no drug on the market at the moment to cure Alzheimer’s, several clinical trials are ongoing and we expect something will be available in the near future.
The research ‘Serial position effects in the Logical Memory Test: Loss of primacy predicts amyloid positivity” is published in the Journal of Neuropsychology and authored by Davide Bruno, Kimberly D. Mueller, Tobey Betthauser, Nathaniel Chin, Corinne D. Engelman3, Bradley Christian, Rebecca L. Koscik and Sterling C. Johnson.