Have you ever been in a situation where you forget where you left your keys or an important piece of paper? Perhaps you went to a shopping centre and forgot where you parked the car, or stumbled on your own child’s name.
It’s easy for people to blame it on a ‘senior moment’, but new research from the University of California in Irvine, published in the Neuron Journal, has found that these so-called senior moments are completely selective.
The researchers say it isn’t uncommon for over-60s to forget things from time to time, but there isn’t actually scientific proof to support claims these lapses in memory are simply a part of getting old. Rather than senior moments, memory problems could actually be the early warning signs of serious cognitive issues such as Alzheimer’s disease.
For their study, researchers analysed brain imaging to determine memory differences between older and young adults. Zachariah Reagh, the study’s first author, said that there is still very little information available when it comes to the impact ageing has on the neural system.
The study analysed 20 young adults aged between 19-31 and 20 older people aged between 64-89. All participants as part of the research were healthy in terms of cognitive function. Each group was given a location memory task and an object memory task in an fMRI scanner. These scanners look at blood flow within the brain and allows researchers to analyse the parts of the brain each participant is using for the tasks.
Michael Yassa, Director of the Center for the Neurobiology of Learning and Memory at the University of California, said that older people typically struggled with the object task, which required them to learn pictures of everyday objects and then distinguish them from new images of new objects.
“Some of the pictures were identical to ones they’ve seen before, some were brand new, and others were similar to what they’ve seen before – we may change the colour and size,” Yassa said. “We call these tricky items the ‘lures’. And we found that older adults struggle with these lures. They are much more likely than younger adults to think they’ve seen those lures before.”
The second task saw participants figure out objects that simply changed their locations. For this task, older people were better than the younger ones.
“This suggests that not all memory changes equally with ageing,” Reagh said. “Object memory is far more vulnerable than spatial memory, at least in the early stages,” Yassa explained.
In many cases, problems associated with spatial memory and navigation can occur if someone is living with Alzheimer’s disease.
The scans during these tests discovered that a decline in object memory actually came down to a loss of signalling in the part of the brain known as the anterolateral entorhinal cortex.
“The loss of fMRI signal means there is less blood flow to the region, but we believe the underlying basis for this loss has to do with the fact that the structural integrity of that region of the brain is changing,” Yassa said of the findings. “One of the things we know about Alzheimer’s disease is that this region of the brain is one of the very first to exhibit a key hallmark of the disease, deposition of neurofibrillary tangles,” the study’s authors wrote.
That said, the study didn’t find memory differences related to age in the posteromedial entorhinal cortex part of the brain, which typically plays a role in spatial memory. Researchers concluded that the brain ageing process is selective.
“Our findings are not a reflection of general brain ageing, but rather specific neural changes that are linked to specific problems in object but not spatial memory,” Yassa added.
Researchers are now working with more adults to determine if fMRI scans could be used as a tool to diagnose Alzheimer’s disease early on.