What Causes Cognitive Decline?

Posit Science

As we grow older, many of us notice that although our experiences have made us wiser, our memory and thinking have slowed down a little. Usually, this is a normal, if unwelcome, part of healthy aging, and can be managed or even alleviated with some work. But more significant memory loss can be a sign of Alzheimer's disease (AD) or another serious condition. Here are a few definitions of the causes of cognitive slowing in maturity.

Normal Age-Related Cognitive Changes
Studies confirm that the ability to remember details about our experiences, to manipulate multiple bits of information at the same time, and to identify the source of what we have learned often declines as we get older. This process actually begins as early as age 30, though it accelerates and becomes more noticeable after age 50. Although these cognitive changes can be annoying -- and ultimately, can limit your activities and interests -- they are part of normal aging. Recent research has indicated that keeping your mind engaged in new and challenging activities can help to prevent or reverse this normal "cognitive decline."

Mild Cognitive Impairment (MCI)
Mild cognitive impairment (MCI) is a term that's used to describe a more serious kind of memory decline. Like those aging normally, people with MCI may complain their memory isn't what it used to be, and their loved ones might agree. But in addition to these general complaints, they also do worse on certain memory tests compared to others in their age group. Unlike in Alzheimer's disease and other forms of dementia, though, people with MCI do not show impaired judgement.

Scientists aren't certain exactly how many people have MCI. Estimates range from 1 percent to 26 percent of Americans age 65+. For some people, MCI represents a transitional period between the mild and manageable memory problems associated with normal aging, and the debilitating symptoms of AD. Estimates vary, but a number of studies suggest that about 10 percent of those with a specific type of memory-related MCI go on to develop AD each year.

For more info on MCI, visit the Mayo Clinic.

Alzheimer's Disease
Alzheimer's is the most common type of dementia. Currently an estimated 4.5 million Americans are afflicted with the disease. Unless effective therapies or cures are found, that number is expected to more than triple by 2050 as the baby boom ages and the number of people surviving into their 70s, 80s and 90s increases. That's because older people are much more likely to get Alzheimer's: While less than 10 percent of people age 65+ have Alzheimer's, over 47 percent of people age 85+ do.

Next: Other forms of dementia >