Mild cognitive impairment (MCI)

DEFINITION

Mild cognitive impairment (MCI) is an intermediate stage between the expected cognitive decline of normal aging and the more serious decline of dementia. It can involve problems with memory, language, thinking and judgment that are greater than normal age-related changes. If you have mild cognitive impairment, you may be aware that your memory or mental function has “slipped.” Your family and close friends also may notice a change. But generally these changes aren’t severe enough to interfere with your day-to-day life and usual activities.

Mild cognitive impairment may increase your risk of later progressing to dementia, caused by Alzheimer’s disease or other neurological conditions. But some people with mild cognitive impairment never get worse, and a few eventually get better.

CAUSES

There’s no single cause of mild cognitive impairment (MCI), just as there’s no single outcome for the disorder. Symptoms of MCI may remain stable for years, progress to Alzheimer’s disease or another type of dementia, or improve over time.

Current evidence indicates that MCI often, but not always, arises from a lesser degree of the same types of brain changes seen in Alzheimer’s disease or other forms of dementia. Some of these changes have been identified in autopsy studies of people with MCI. These changes include:

• Abnormal clumps of beta-amyloid protein (plaques) and microscopic protein clumps characteristic of Alzheimer’s disease (tangles)
• Lewy bodies, which are microscopic clumps of another protein associated with Parkinson’s disease, dementia with Lewy bodies and some cases of Alzheimer’s disease
• Small strokes or reduced blood flow through brain blood vessels

Brain-imaging studies show that the following changes may be associated with MCI:

• Shrinkage of the hippocampus, a brain region important for memory
• Plaques throughout the brain
• Enlargement of the brain’s fluid-filled spaces (ventricles)
• Reduced use of glucose, the sugar that’s the primary source of energy for cells, in key brain regions

SYMPTOMS

Your brain, like the rest of your body, changes as you grow older. Many people notice gradually increasing forgetfulness as they age. It may take longer to think of a word or to recall a person’s name.

But consistent or increasing concern about your mental performance may suggest mild cognitive impairment (MCI). Cognitive issues may go beyond what’s expected and indicate possible MCI if you experience any or all of the following:

• You forget things more often.
• You forget important events such as appointments or social engagements.
• You lose your train of thought or the thread of conversations, books or movies.
• You feel increasingly overwhelmed by making decisions, planning steps to accomplish a task or interpreting instructions.
• You start to have trouble finding your way around familiar environments.
• You become more impulsive or show increasingly poor judgment.
• Your family and friends notice any of these changes.

If you have MCI, you may also experience:

• Depression
• Irritability and aggression
• Anxiety
• Apathy