Is cognitive decline inevitable?

The June presidential debate sparked conversations around cognitive health and aging.

You might also be wondering, is cognitive decline inevitable?

"It's one thing if I can't remember where I put my keys. It's another if I can't find my keys because I put them in the freezer," says Nathan Goldstein , MD, a geriatrician, palliative care physician and Chair of the Department of Medicine at Dartmouth Health .

What's normal and what isn't?

Cognition is the ability to learn, remember, and make judgments. It peaks at age 30.

Starting in your 60s, you may notice normal cognitive aging when your brain's processing speed slows down. You may not readily recall the name of a childhood friend or forget where you parked the car. You might take longer to calculate a restaurant tip in your head.

But losing your train of thought frequently, getting lost in the grocery store or being unable to balance your checkbook can signal something more serious.

"One thing we look for is loss of function—being unable to get dressed, getting lost and not being able to do your finances as you used to," Goldstein says. "And sometimes those changes can be subtle."

Normal cognitive aging doesn't mean a steep decline

Normal cognitive aging is different from cognitive decline conditions like mild cognitive impairment (MCI) or dementia.

For most people, symptoms for dementia and MCI are subtle and slow over time. But noticeable, too.

"Patients we test or monitor will describe short-term memory problems, like losing track of what they're thinking about or getting easily distracted," says Lisa Furmanski, MD , a geriatric physician at Alice Peck Day Memorial Hospital . "It can be vague. But it's just a sense that something is different.

MCI is when people experience more memory or thinking problems than other people their age. Diabetes, depression, and stroke may increase a person's risk for MCI.

Dementia is an umbrella term for symptoms caused by abnormal brain changes. Dementia triggers a decline in thinking skills severe enough to disrupt daily life and independence. Alzheimer's disease is the most common cause of dementia, accounting for 60 to 80% of dementia cases.

Walking speed and unexplained falls

Another early sign of MCI or dementia is walking issues and falls, Furmanski says. A person might be shuffling, leaning to one side, walking slower or experiencing unexplained falls.

"Patients will say their walking seems off somehow," Furmanski says. "Trying to organize a path to move around obstacles, rugs and your house can be an early sign of cognitive impairment."

A 2022 study found declining cognitive function coupled with slowed walking speed is associated with greater dementia risk in older adults. Gait speed can predict not only dementia but also other geriatric syndromes such as falls, frailty and disability.

But certain health issues can also mimic cognitive decline. Thyroid problems, medication mix-ups, vitamin deficiencies, hearing or vision issues and depression can present symptoms of cognitive decline. Once those issues are treated or corrected, MCI or dementia might be ruled out by your doctor.

The mental toll of cognitive decline

"When diagnosed, people go through all kinds of classic coping responses, like denial, sadness and anxiety, and feeling defensive and angry about what they're seeing or what others are seeing," says Dax Volle , MD, a geriatric psychiatrist at Dartmouth Hitchcock Medical Center and Clinics .

Volle encourages a person diagnosed with mild cognitive impairment or dementia to initiate conversations with their loved ones early on about caregiving and end-of-life planning.

"The hardest part of all this is the uncertainty," Volle says, adding that it's impossible to predict the severity of someone's eventual cognitive decline.

Preventing cognitive decline

"One of the theories is, 'use it or lose it,'" Goldstein says.

Dementia and MCI cannot be reversed or cured. But 40% of dementia cases worldwide can be prevented or delayed by lifestyle factors.

Lack of exercise, poor diet, smoking, heavy alcohol consumption, high blood pressure, diabetes, high cholesterol, depression and untreated sleep apnea are some of the biggest contributors to dementia.

Staying active cognitively , exercise, and eating well can also stave off memory or impairment issues.

Diagnosis, treatment and support

Dartmouth Health treats some Alzheimer's patients with Lecanemab, a new FDA-approved intravenous infusion therapy that treats early-stage Alzheimer's disease and slows its progression over time.

Advanced diagnostic measures for Alzheimer's include using biomarkers taken from a skin biopsy or a lumbar puncture, and neuroimaging techniques to understand the disease better, Volle says. Meanwhile, a new study published in July shows that a blood test can diagnose Alzheimer's with 90% accuracy.

If you or a loved one has dementia or MCI, the Aging Resource Center at Dartmouth Health's Geriatric Center of Excellence offers free Alzheimer's Association workshops, advanced care planning, caregiver education classes, events and more.

Just because your brain peaks at age 30 doesn't mean cognitive impairment or dementia is in your future.

"I wouldn't say cognitive decline is inevitable," Goldstein says. "But normal cognitive aging is just a part of life."

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