TORONTO - When Susie McKinnon was a child, she had a stock answer when anyone asked if she remembered an event in her life.
"Not really,'' McKinnon, now 60, would reply.
McKinnon has no episodic memory. She can't form memories about events in her life, or relive her past by calling up images of bygone times.
The condition is called severely deficient autobiographical memory, or SDAM, a name devised by researchers at the Rotman Research Institute at Toronto's Baycrest Health Sciences Centre, who have studied McKinnon and two other people with similar memory deficits.
The Baycrest team recently published on the newly described condition in the medical journal Neuropsychologia.
McKinnon has been told she was a bit of an eccentric kid—a tomboy who read the encyclopedia for fun.
McKinnon knows these facts about herself only because she's been told them and has committed them to memory.
In an interview, she says she only realized her memory was different when she was 21 or so. Because she couldn't replay mental movies of her past, she made up stories, often embroidering details—some erroneous—on tales she had heard her parents or her brothers tell, or using family photos as a jumping off point.
A friend who was studying to be a physician's assistant had an assignment to devise a quiz to detect early signs of dementia and needed someone to test it on. McKinnon's responses struck her as unusual, prompting McKinnon to start asking others if they actually remembered episodes of their past.
She was flabbergasted by the replies.
"I just assumed everyone was making up stories, because I certainly was,'' she says, adding she thought this was an accepted part of social interaction.
"You just think up funny little stories and just keep telling them over and over again. And that makes them true for you.''
Her semantic memory—the part that allows her to learn facts—is fine. Asking if she remembers her high school prom illustrates the difference between the two types of memory.
"If you ask me about prom, I know that I didn't go to prom and I know that I decorated for prom. But that's different from remembering anything about that,'' she says.
McKinnon spent years, off and on, trying to find references to her type of memory issue. Before the Internet, that was tough. But nearly 10 years ago, she happened upon an article on Endel Tulving, a giant in memory studies who is a scientist emeritus at Baycrest. Tulving opined that there were probably people who don't have episodic memory—in other words, people just like McKinnon.
She eventually reached out by email to another neuroscientist at Baycrest, Brian Levine, who has since studied McKinnon. Why not Tulving?
"Well, if you were living back in the time of Freud and you had interesting dreams, you wouldn't go right to Freud. You'd probably go to somebody who works with him to see if they thought you were crazy or not,''' McKinnon says.
She's ecstatic to finally have answers and to know that there are other people like her. And while in Toronto working with the Baycrest team, she got a chance to meet and thank Tulving.
"He gave me the words, he gave me the concept that matched me,'' she explains.
McKinnon says she has no angst about her memory deficit, though she admits to occasionally feeling wistful when she hears friends recounting experiences from their past.
"I know that I've had some marvellous experiences, but I'll never re-experience them the way other people do.''
Still, there are pluses. McKinnon lives in the moment and isn't plagued by self-doubts about how she handled a situation, for instance. And she's the first to admit she can't hold a grudge.
"It's impossible for me to stay mad at somebody because I don't remember,'' McKinnon says with a chuckle.
ALSO ON HUFFPOST
Ready for a pop quiz? Before reading any further, focus on the words to the left for one minute, then read (or reread) another article. When you're done, write down as many of the words as you can remember and return to this page to count up your total. Find out what your score means...
How'd you do? Recalling five or more of the words means your baseline short-term memory is in good shape. But if you came up with fewer, don't panic. maybe you were distracted by a text message, or maybe something else on the page caught your attention while you were reading the list (research shows that simply being unfocused can make it nearly impossible to add new information to your memory bank). Or maybe you just need to incorporate some brain training, which can activate and strengthen neural connections over time, allowing you to call up stored information faster. Gary Small, MD, director of the UCLA Longevity Center, who designed our test and uses a similar one to help diagnose memory problems in his patients, believes that certain behavioral techniques can help you stay sharper, longer. If you're perpetually misplacing your keys and forgetting to pick up milk at the grocery store, use these tactics to boost your memory today--and help prevent its decline down the road.
After tracking the social behaviors of more than 700 people over 15 years, Australian researchers found that those who maintained more close friendships scored better on memory tests (recalling symbols, pictures, and words). Being in regular contact with friends can keep you on your toes by engaging the problem-solving regions of your brain (as when you debate your latest book club pick or help a friend through a crisis). "It's important to be socially connected from a young age so that the lifestyle patterns you develop become ingrained," says Peter Snyder, PhD, chief research officer of the Lifespan Hospital System in Rhode Island. "We've found that when people prioritize these relationships, they also protect their brain function."
As long as it interests and challenges you, the particular pastime doesn't matter -- it could be reading books in a genre you usually avoid, learning to play an instrument, or taking a new exercise class. A study by researchers at the Columbia University College of Physicians and Surgeons found that people with more than six intellectual, physical, or social leisure activities were 38 percent less likely to develop dementia -- and with each additional hobby, their risk decreased by another 8 percent. The fresh neural connections established as you take in new information can help build up what's called cognitive reserve--the brain's ability to resist memory loss. And the sooner you find new passions, the better: A 2012 study conducted at the University of California, Berkeley, found that people who performed more mentally stimulating activities throughout their lives had lower levels of a certain destructive protein associated with Alzheimer's.
Many studies have shown that depression is linked to memory problems, but keeping your brain sharp requires more than just staving off the blues -- you need to actively practice positivity. A 2013 study in the journal Cognition and Emotion found that older adults who experienced positive emotions improved their memory by roughly 19 percent. "Positive moods are thought to trigger the release of the chemical dopamine in brain regions involved in memory, which may help improve recall," says study coauthor Ellen Peters, PhD, professor of psychology at The Ohio State University. If you want to reap the same benefits, try practicing meditation -- one study found that the proven stress buster can help increase dopamine levels.
A study from the Rotman Research Institute found that bilingual Alzheimer's patients began experiencing symptoms of the disease five years later than patients who spoke only one language. "When you think in two languages, your brain cells may be working twice as hard," explains Small. "And the more often you fire up those neurons, the stronger they get." But it's use it or lose it: "If these connections aren't reinforced regularly -- as in the case of a neglected foreign language you learned decades ago -- they fade," says Neal Barnard, MD, an adjunct associate professor at the George Washington University School of Medicine and Health Sciences.
Picturing yourself completing a task can help ensure that you remember to get it done. Researchers at the University of Arizona recently conducted a study in which participants were asked to memorize lists of words describing personality traits; having subjects imagine themselves acting out the traits proved the most effective technique for boosting their ability to immediately recall the words. The findings suggest that this technique could work for everyday memory tasks, from remembering to return shoes at the mall (picture yourself at the cash register) to remembering to stop by the dry cleaner's on your way home from work (imagine walking out with your clothes).
Whether you do it by changing careers or simply taking on more responsibilities at the job you have, finding something that pushes you out of your comfort zone can help protect against memory-deteriorating diseases. One study published in Neurology reviewed the work histories of people with and without Alzheimer's and found that those who developed the disease had fewer mentally taxing assignments. Researchers believe that the mental stimulation of more demanding jobs can help shore up cognitive reserves and stave off dementia. Says Snyder, "Routinely challenging yourself with projects that require you to multitask and solve problems fortifies systems in the brain that are important for memory." Help Researchers Learn More About Memory Loss One of the best things you can do to help scientists find a cure for Alzheimer's disease is to join the Alzheimer's Prevention Initiative, a new registry where you can volunteer to participate in medical surveys and clinical trials. You don't have to suffer from dementia to help -- the more people (both healthy and sick) who join, the more researchers can learn about what's going on in the human brain. Sign up at Registry.EndAlzNow.org.