Alzheimer's Disease Archive

The shift from this condition to dementia is not necessarily inevitable.

 Image: © gradyreese/Getty Images

Will I get dementia? That common question takes on urgency if you have mild cognitive impairment (MCI), a slight but noticeable change in memory and thinking skills. But the progression from MCI to dementia is not automatic. In fact, MCI is not always permanent. "It depends on the underlying cause," says Dr. Joel Salinas, a neurologist at Harvard-affiliated Massachusetts General Hospital.

What are the causes of MCI?

MCI is not dementia (see "What is dementia?"), but it's not normal thinking, either. It often stems from disease or treatments for disease, including

Practicing a new and challenging activity is a good bet for building and maintaining cognitive skills.

Your brain has the ability to learn and grow as you age — a process called brain plasticity — but for it to do so, you have to train it on a regular basis.

"Eventually, your cognitive skills will wane and thinking and memory will be more challenging, so you need to build up your reserve," says Dr. John N. Morris, director of social and health policy research at the Harvard-affiliated Institute for Aging Research. "Embracing a new activity that also forces you to think and learn and requires ongoing practice can be one of the best ways to keep the brain healthy."

In the journals

Older adults who develop hearing loss are more likely to experience greater cognitive decline and develop dementia than their counterparts without hearing problems, according to a meta-analysis published online Dec. 7, 2017, by JAMA Otolaryngology — Head and Neck Surgery. Researchers examined data from 36 studies including more than 20,000 people who underwent both cognitive evaluations and hearing tests. Those with age-related hearing loss were more likely to have cognitive impairment or a diagnosis of dementia.

The study found a small but statistically meaningful association between hearing loss and a variety of specific cognitive abilities, including executive function, memory, processing speed, and visuospatial ability (how you recognize shapes and sizes and estimate the distance between two objects). The association between hearing loss and weaker cognitive skills was still strong even after accounting for risk factors like high blood pressure and smoking.

If you are noticing problems in yourself or a loved one, here's where to turn for help and support.

 Image: © simarik/Getty Images

You're talking with a friend about a movie you saw recently, but can't remember the actor's name. Last week you found yourself upstairs, but couldn't remember what you came up to look for. Your keys are always missing. You worry: are these normal memory lapses or early signs of Alzheimer's disease or another form of dementia?

"Because there has been so much attention paid lately to the aging baby boomer population, I think Alzheimer's disease is getting a lot of attention, which is leading a lot of people to believe they may have the condition," says Dr. Suzanne Salamon, associate chief of the gerontology division at Beth Israel Deaconess Medical Center and assistant professor of medicine at Harvard Medical School.

News briefs

You've probably heard about tests to measure chemicals in the blood that indicate chronic inflammation in the body. They are sometimes used to estimate risk for heart disease. But what about using these kinds of biomarkers to gauge your risk for declining brain health? A study published Nov. 1, 2017, in Neurology found that having certain inflammatory markers in midlife was associated with brain shrinkage and poor memory in older age.

Researchers measured five inflammation biomarkers in about 1,600 middle-aged people and gave them brain scans and a memory test about 25 years later. Compared with people with no elevated inflammation markers, people with high levels of three or more biomarkers scored lower on the memory test and had about 5% shrinkage in the hippocampus and other parts of the brain associated with Alzheimer's disease.

Research we're watching

Among people who have atrial fibrillation (afib), those who take anti-clotting medications may be less likely to develop dementia later in life than those who don't take the drugs, a new study finds.

Afib, a disorder marked by a rapid, irregular heartbeat, raises the risk of stroke as well as dementia. Anti-clotting drugs are known to lower the risk of stroke, but the drugs' effects on dementia weren't clear. So Swedish researchers examined hospital and pharmacy registry data from nearly half a million people who were diagnosed with afib between 2006 and 2014.

In the journals

 Image: © Purestock/Thinkstock

If you have persistent trouble detecting or identifying odors, that may be an early sign of dementia, according to a study in the Sept. 25, 2017, Journal of the American Geriatrics Society. Almost 3,000 older adults, ages 57 to 85, who did not have dementia were asked to detect and identify five common odors like peppermint, fish, orange, rose, and leather. Five years later, the researchers found that almost half of those who performed poorly on the smell test (were either unable to detect the odors or unable to identify what the smells were) had been diagnosed with dementia. In comparison, 79% of those who scored high on the smell test did not have dementia.

The results only show an association between poor sense of smell and dementia, but the researchers noted that a smell test could be a simple way to identify high-risk people. It isn't clear how sense of smell and dementia may be linked, but the researchers speculated that underlying causes of dementia, like amyloid plaque buildup and tau tangles in the brain, also may affect the olfactory (sense of smell) system.

MCI can be tough to identify, but there may be ways to postpone, and possibly prevent, its impact on memory and thinking.

Everyone has the occasional bout of forgetfulness, whether it's misplacing your keys or blanking out on a name. But if these episodes become frequent or interfere with daily life, you may have mild cognitive impairment, or MCI.

MCI falls somewhere between the usual cognitive decline of normal aging and the more serious signs of dementia and Alzheimer's disease. An estimated 10% to 20% of adults older than 65 have MCI, according to the Alzheimer's Association. But this gray area of brain health is often difficult to detect.

Factors that harm your heart may be bad for your brain.

 Image: © Nik01ay/Thinkstock

During middle age, factors that leave you prone to a heart attack or stroke — high blood pressure, diabetes, and smoking — may raise your risk of developing dementia a quarter-century later, new research suggests. All three things affect your vascular (blood vessel) health.

The recent study, which adds to the growing evidence linking heart health to brain health, has elements that make findings especially reliable, says Dr. Gad Marshall, a Harvard Medical School assistant professor of neurology. "For understanding the vascular risks for dementia, this study is as close to definitive as we can get," he says.

On call

 Image: © Digital Vision/Thinkstock

Q. I have been seeing a lot about brain training programs to improve memory. Do they really work?

A. Brain training programs promise to preserve cognitive abilities, but so far research has not found they can delay or prevent brain decline.