Partial recall: Memory experts explain what's normal forgetfulness — and when you should worry

Do you know where you left your keys? What's the name of that Oscar nominated actor — the one who's not the frontrunner? Is today Tuesday? Do you remember when you were vice president? And is the possibility that you're not sure of any of those things terrifying to you? Roughly 6 million Americans currently have dementia — a number expected to only increase over the next decade as the U.S. population ages.

And because of dementia's high hereditary connection, it means the children and grandchildren of all those individuals face an unnerving risk in our own futures as well. In a world of escalating demands, sleep deprivation and distraction, how can we aging Gen Xers and Millennials — especially those of us with a legacy of dementia in our families — distinguish between typical stress and age related forgetfulness and something more concerning? And is there anything we can do to stave it off?

As we get older, our bodies change, and that includes the squishy stuff between our ears. The brain shrinks, blood flow to the region decreases, hormones shift, and suddenly you're struggling to recall the name of that person who got kicked out of the dorm freshman year.

"With aging in general, memory goes down," says Charan Ranganath, PhD., author of the new book "Why We Remember: Unlocking Memory's Power to Hold on to What Matters." This can make it very hard to tell the difference in the earliest stages of Alzheimer's, "where it's just barely starting to have an effect," he says.

Compounding the confusion is that in our anxious world, many of us feel more scattered than ever. I am still haunted by my experience of a few months ago, when an exhausting, overworked schedule turned my ability to compete even simple tasks into a test of mettle.  "You had a glimpse into what dementia feels like," Sara C. Mednick, author of "The Power of the Downstate: Recharge Your Life Using Your Body's Own Restorative Systems" had told me at the time. It felt like a nightmare.

"Chronic stress is terrible for the prefrontal cortex," says Ranganath. "Technology isn't a bad thing, but we get a lot of alerts from our phones or our watches. Every time I shift my attention and then I go back to what I was doing before, my prefrontal cortex is working just to get back up to speed on what I was doing before I got distracted. When you're constantly getting distracted like that, it uses up a lot of those attentional resources."

This can leave us feeling tired, with a harder time focusing.

"It's stressful," Ranganath says. "That will reduce your ability to focus on what's distinctive, and stay focused on what's happening."

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In those circumstances, it's challenging to make memories, let alone summon them. Sometimes, though, we forget stuff because it literally just doesn't make a big impression in our minds.

"When we form a new memory, there's this ecosystem of other memories that we're dropping it into," Ranganath explains. "It's not just a matter of having a memory, but being able to access it the right way. If I have a desk full of cluttered yellow Post-it notes and I'm trying to find the one where I wrote my password for this email account I never use, I'm never going to find it amidst those other ones. But if I'm looking for one, and it's hot pink, it sticks out relative to everything else. In the same way, if you have a memory that is very distinctive from everything else in that memory ecosystem, it's going to be easy to find. Sometimes it happens, but other times it requires intention. Many things compete for our attention. The problem is, all those factors sap the prefrontal cortex."

How do we know, then, what falls in the range of whatever passes for "normal" forgetfulness and what's concerning?

"Occasional forgetfulness, such as misplacing keys or forgetting an appointment, is a common aspect of stress or aging," says Elvis Rosales, the clinical director at Align Recovery Centers. "These instances are usually sporadic, and do not significantly interfere with daily life. However, when forgetfulness becomes more frequent, impacts one's ability to complete everyday tasks, or is accompanied by changes in mood, behavior and personality, it may signal something more serious, such as the early stages of dementia."

Rosales adds that "Especially for Gen Xers and Millennials, distinguishing between normal aging and potential early signs of cognitive decline is crucial. For those with a family history of dementia, this awareness becomes even more critical. It's well-documented that genetics play a role in the risk of developing conditions such as Alzheimer's disease. But," he says, "lifestyle choices and environmental factors also significantly impact cognitive health."

Regular exercise, a diet rich in antioxidants and omega-3 fatty acids, staying mentally active through learning and problem-solving activities and ensuring consistent social engagement can all contribute to a healthier brain, Rosales advises. "Furthermore, managing stress through mindfulness practices, adequate sleep and seeking professional help when needed are pivotal in promoting overall mental well-being." 

Ranganath also says that our loved ones can be our best barometers of how we're doing cognitively. "My rule of thumb would be if somebody came in complaining that their memory was getting worse, often their memory was okay," he says. "But if a relative came in telling them that their memory was getting worse, then there was something wrong. Often that's a sign, if people around are aware you're forgetting more."

He says that other potential red flags include heightened disorientation. "If you find yourself getting totally lost and disoriented, not just lost in the sense of, you can't find your way to the place, but lost in the sense that you don't even know where you are, or if you find yourself not knowing what month it is, that's a problem. If you don't remember something that you said in conversation, that's normal. If you don't remember that the conversation ever took place, that might be something to be concerned about."

Smart self-monitoring and self-care doesn't just mean trying to stay on alert for memory loss, though. "It's also important to address the psychological impact of having a family history of dementia," says Carlos Escobar, clinical director at Real Recovery in Florida. "The knowledge of a potential increased risk can be anxiety-inducing. Seeking support through counseling or support groups can provide emotional relief and practical strategies to manage this concern healthily."

And, he says encouragingly, "While a genetic predisposition can increase risk, it's also empowering to know that lifestyle choices can play a pivotal role in brain health. Engaging in regular physical activity, maintaining a healthy diet, keeping mentally active through learning new skills or hobbies, and staying socially connected are foundational steps that can contribute to staving off cognitive decline. Additionally, routine medical check-ups that include cognitive screening tests can be a proactive approach to monitoring brain health over time."

While the risks and horrors of dementia are serious, the occasional brain fart, particularly when we're sleep-deprived or stressed, shouldn't be something to get even more sleep-deprived and stressed about. Ranganath says, "I think where people really worry needlessly is when they get into, 'I can't think of the name of that actor. What's his name again? Oh, God, it's on the tip of my tongue.' And then it comes to them a week later, that's fine. That's totally normal."