You see an actor on TV and have trouble remembering her name — that “tip of the tongue” sensation. Or you walk into a room to retrieve something only to forget what it was you came to get, a phenomenon known as the doorway effect. These sorts of things happen to most of us as we get older.
Mild cognitive impairment (MCI) is a stage between cognitive changes associated with normal aging and the more serious decline of dementia.
“MCI is an umbrella term for an early stage of loss of cognitive, or thinking, ability,” says Tamar Gefen, a neuropsychologist at Northwestern Memorial Hospital. “An individual does not lose their ability to carry out their typical activities of daily living. They have cognitive problems but can still work, can still drive. No one would necessarily from the outside know that there’s anything wrong with their thinking.”
The changes, however, are serious enough to be noticed by the person affected and by family caregivers and others who know them well. Ardeshir Hashmi, M.D., section chief of the Center for Geriatric Medicine at the Cleveland Clinic, likens MCI to borderline diabetes, a condition that develops before a person gets type 2 diabetes.
“That is what MCI is to memory impairment,” he says. “You don’t have dementia at the time but are you borderline or at risk of developing it in the future. It’s sort of a warning stage.”
There are two categories of mild cognitive impairment.
Amnestic MCI affects memory. A person may start to forget information they would have recalled easily before, such as the contents of a recent conversation, an appointment they’ve been reminded of multiple times or a recurring event like a close relative’s birthday.
Non-amnestic MCI affects other thinking skills. You can remember things, but other ways you engage your brain become more difficult. These might include:
• Your ability to make sound decisions or understand instructions.
• Spatial ability — you have trouble navigating through your environment or gauging distances.
• Language — losing your train of thought or forgetting familiar words when speaking.
• Calculation — difficulty with anything that involves math, for example.
What’s behind the brain fog?
According to the Alzheimer’s Association, 12 to 18 percent of people age 60 or older are living with mild cognitive impairment. An estimated 10 to 15 percent of individuals with MCI develop dementia each year.
“Some people [with MCI] will be in the early stages of a neurodegenerative process, such as Alzheimer’s disease,” says C. Munro Cullum, a neuropsychologist at the UT Southwestern O’Donnell Brain Institute. “Others may be experiencing cognitive decline or memory loss due to vascular risk factors, such as a series of small mini-strokes or hyper-cholesterol building up over many years, leading to reduced blood flow through blood vessels in the brain.”
“There are people who have MCI and remain stable, and some actually get better and revert back to normal cognition,” Hashmi says. “Depending on the underlying cause, it may be a treatable thing.”