The Dose23:42What happens to my memory as I age?
Bill VanGorder likes to keep his brain busy.
The 81-year-old chief policy and education officer for the Canadian Association of Retired Persons (CARP) in Halifax also holds volunteer board positions with a number of other groups, all while helping his wife’s business.
Despite his active lifestyle, VanGorder acknowledges that his memory as an octogenarian isn’t as sharp as it used to be.
“I’m very involved in theatre … and I find that learning lines is not as easy as it was 40 years ago,” he said. “I used to be able to read a script over and over and commit it to memory. I now find that, in learning my lines, I have to write them out.”
Many people assume that memory degrades as people grow older, but Toronto Metropolitan University (TMU) neuroscientist Natasha Rajah says oftentimes, the ability to retain memory remains intact in old age. However, it can become harder to remember certain things as our aging brains influence what we recall and how we retrieve information. Episodic memory, which holds our unique past personal experiences, is more sensitive to memory loss with age, she added.
What happens to memory as we get older?
Rajah, who is also Canada Research Chair in sex, gender and diversity in brain health, memory and aging at TMU, says there’s some debate about when memory decline begins.
Some researchers believe that the decline begins between 20 to 40 years old, with a steeper decline in older age.
“My research has shown that [episodic memory] remains relatively stable until midlife, and then starts to slowly decline at midlife and then accelerates in older age,” Rajah told The Dose host Dr. Brian Goldman.
A 2016 study co-authored by Rajah found “age-related deficits in context memory beginning at midlife.”
While episodic memory tends to decline, Rajah says there’s evidence that semantic memory — facts and knowledge — actually improves with age, “because we’re acquiring new world knowledge.”
Source memory, which represents the ability to remember perceptual, spatial and temporal details about past experiences, is also sensitive to the effects of aging.
For instance, a person might remember attending a friend’s birthday, even if that same person might have trouble remembering when the party began or ended.
Item memory, which allows us to remember someone when we meet them at the grocery store, for example, remains intact into older age, according to Rajah.
Memory and the aging brain
Like many other organs, the brain’s physical structure changes as people grow older.
“When we are young, it does have a greater capacity to, just like the rest of our body, form new cells, form new connections,” said Teresa Liu-Ambrose, a physical therapy professor and Canada Research Chair in healthy aging at the University of British Columbia.
As people age, their brains become more precise and begin a process called pruning — where the brain prioritizes neuronal connections to enable essential skills and essential memories that individual people cultivate over time, according to Liu-Ambrose.
Additionally, the brain loses mass.
The hippocampus, a key cerebral structure involved in converting short-term memories into long-term memories, shrinks over time beginning around the mid-to-late 50s, according to Rajah.
The prefrontal cortex — important for encoding and retrieving memories — also declines with age, typically around the age of 30, according to Rajah.
“That said, we do also know that the brain’s capacity to keep changing over time is retained,” said Liu-Ambrose.
What this ultimately means is that it becomes harder to remember certain memories, but most people with healthy brains maintain the ability to form new memories and learn new skills.
Dementia versus normative aging
Rajah says there are “profound” differences between memory decline due to normative aging and conditions like dementia.
“[Neurodegenerative diseases] affect the activities of daily living,” she said. “Like if you take a car and you get lost while driving because you can’t navigate your way back home.”
Someone living with Alzheimer’s disease experiences a decline in episodic memory, as well declines in semantic memory and an overall decline in executive function.
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“It won’t just be memory … there might also be some language difficulty and word-finding difficulty,” said Rajah, adding that the evidence of memory degradation typically gets worse as the illness progresses.
In contrast, someone experiencing memory decline due to old age might momentarily forget where they parked their car, or have some trouble finding a word that’s metaphorically on the tip of their tongue.
“The tip of the tongue phenomenon actually does increase with aging,” Rajah said. “But what’s funny is that the memory is actually there.”
How can we improve our memory as we grow older?
Memory decline with age is common, but Rajah says there’s variation in when the decline happens and to what extent it takes place.
“There are people that are maintainers,” she said. “There’s people that decline steeper, and they’re called decliners, in the field.”
“And then there’s also people that show some average decline, but nothing notable.”
Rajah says maintainers typically have higher education, come from a higher socioeconomic status, often have a better diet and also exercise.
But she says anyone can work on maintaining their memory as long as they take steps to help their brains remember events — and if they work on their physical health.
Rajah says using a notebook, tablet or smartphone to organize daily tasks, setting reminders and alerts for things like medication and appointments, as well as relying on mnemonic devices like repetition to remember events can all help improve memory.
Liu-Ambrose emphasizes the importance of physical activity.
“A healthy body is a healthy mind,” she said. “Your brain doesn’t just stop at your neck. It’s fed by your heart, by your lungs. It’s a highly metabolic organ.”
