What is mild cognitive impairment?
Mild cognitive impairment is a condition in which a person experiences a slight – but noticeable – decline in mental abilities (memory and thinking skills) compared with others of the same age. The minor decline in abilities is noticeable by the person experiencing them or by others who interact with the person, but the changes are not severe enough to interfere with normal daily life and activities.
What’s the difference between mild cognitive impairment and decline due to normal aging?
Some gradual mental (cognitive) decline is seen with normal aging. For example, the ability to learn new information may be reduced, mental processing slows, speed of performance slows, and ability to become distracted increases. However, these declines due to normal aging do not affect overall functioning or ability to perform activities of daily living. Normal aging does not affect recognition, intelligence, or long-term memory.
In normal aging, a person may occasionally forget names and words and misplace things. With mild cognitive impairment, the person frequently forgets conversations and information that one would ordinarily remember such as appointments and other planned events.
What is dementia?
Dementia is a general term used to describe a decline in mental function that is severe enough to interfere with daily living.
Does having mild cognitive impairment always lead to the development of dementia?
There are some cases in which the cause of the mild cognitive impairment is due to the effects of a treatable illness or disease. However, researchers have now determined that for most patients with mild cognitive impairment (MCI), the MCI is a point along the pathway to dementia. The MCI is considered the stage between the mental changes that are seen in normal aging and early-stage dementia. MCI can be due to a variety of diseases, such as Alzheimer’s or Parkinson’s disease, just as dementia can be due to a variety of reasons such as Alzheimer’s or Parkinson’s disease, dementia with Lewy bodies, vascular dementia, frontotemporal dementia, and other causes.
According to the American Academy of Neurology, of people aged 65 or older who have mild cognitive impairment:
- About 7.5 percent will develop dementia in the first year after diagnosis of mild cognitive impairment
- About 15 percent will develop dementia in the second year
- About 20 percent will develop dementia in the third year
How common is mild cognitive impairment?
The American Academy of Neurology estimates that mild cognitive impairment is present in about 8 percent of people age 65 to 69, in 15 percent of 75 to 79 year-olds, in 25 percent of those age 80 to 84, and in about 37 percent of people 85 years of age and older.
Symptoms and Causes
What are the symptoms of mild cognitive impairment?
Examples of memory and thinking problems that might be seen in someone with mild cognitive impairment include:
- Memory loss. Forgets recent events, repeats the same questions and the same stories, forgets the names of close friends and family members, forgets appointments or planned events, forgets conversations, misplaces items often.
- Language problems. Has trouble coming up with the desired words. Has difficulty understanding written or verbal (spoken to) information.
- Attention. Loses focus. Is easily distracted.
- Reasoning and judgment. Struggles with planning and problem solving. Has a hard time making decisions.
- Complex decision-making. May struggle, but can complete complex tasks such as paying bills, taking medications, shopping, cooking, household cleaning, driving.
What causes mild cognitive impairment?
All possible causes of mild cognitive impairment have not been completely discovered. In a small number of cases, another condition may be causing the symptoms seen in mild cognitive impairment. Some of the possible conditions include:
- Depression, stress, and anxiety
- Thyroid, kidney or liver problems
- Sleep apnea and other sleep disorders
- Diseases or conditions that affect blood flow in the brain (tumors, blood clots, stroke. traumatic brain injury, normal pressure hydrocephalus)
- Low vitamin B12 levels or other nutrient levels
- Eye or hearing problems
- An infection
- Side effects of certain prescription (for example, anticholinergic drugs used to treat bladder conditions, Parkinson’s disease and depression) or illegal drugs
- History of alcoholism
Many of these causes of mild cognitive impairment are treatable.
Most cases of MCI, however, are due to a variety of diseases, such as Alzheimer’s or Parkinson’s disease. (Similarly, like dementia is due to a variety of diseases such as Alzheimer’s or Parkinson’s disease, dementia with Lewy bodies, vascular dementia, frontotemporal dementia, and other causes.)
Diagnosis and Tests
How is mild cognitive impairment diagnosed?
First, your doctor will perform a thorough medical history including asking about current and previous diseases and illnesses, current and previous medications, and family history of memory problems and dementia. He or she will also ask you (and your close friend or family members) if there have been noticeable changes in your ability to function in your usual day-to-day living and activities.
Your doctor will also look for other causes of the symptoms of mild cognitive impairment (see, “what causes mild cognitive impairment”). Ruling out other causes usually involves blood tests and possibly brain scans, such as magnetic resonance imaging (MRI) scan.
Short mental status tests may be given to assess memory, attention, short-term recall, and other brain functions. Sometimes more in-depth thinking skills testing, called neuropsychological testing, is ordered. These tests assess memory, planning, decision-making, ability to understand information, language and other complicated thinking tasks.
No single test should be used to make a diagnosis of mild cognitive impairment or dementia. Your doctor’s clinical judgment is also necessary. He or she will likely be able to confirm a diagnosis of mild cognitive impairment if you show impairment on the kinds of tests mentioned above but are otherwise functioning well.
Management and Treatment
How is mild cognitive impairment treated?
No medications are currently approved to treat mild cognitive impairment. Drugs used to treat the symptoms of Alzheimer’s disease have been tried with mixed results (some trials have shown a benefit in using these drugs for mild cognitive impairment; others have not). Most recently, a worldwide review of studies of mild cognitive impairment by the American Academy of Neurology concluded that drugs used to treat Alzheimer’s disease showed no cognitive benefit or slowdown in progression of mild cognitive impairment to dementia. Trials of others drugs including NSAIDs, ginkgo biloba, and vitamin E have not shown clear benefit.
If testing has determined a treatable medical condition as the cause of the mild cognitive impairment, the patient should be treated for those conditions. Also, medications may be prescribed if behavioral or psychiatric symptoms (for example, agitation, anger, anxiety, sleep problems, depression, delirium) are present and interfering with the patient’s quality of life.
Are there risk factors for the development of mild cognitive impairment?
Scientists know that the strongest risk factors for the development of mild cognitive impairment are the same as those for dementia: older age, family history of dementia, and conditions that increase the risk of cardiovascular disease including high blood pressure, high cholesterol levels, diabetes, obesity, and stroke.
What can I do to help my brain health if I have been diagnosed with mild cognitive impairment?
According to the American Academy of Neurology’s practice guideline for patients with mild cognitive impairment, the best thing you can do to maintain your brain health is to exercise (particularly aerobic exercise) twice a week.
Although there is no clear-cut proven link that doing any of the following will help slow memory and thinking skill decline, these are general recommendations for maintaining good health.
- Maintain good blood pressure, cholesterol levels, and blood glucose levels
- Stop smoking and avoid excess drinking
- Eat a healthy diet
- Maintain appropriate weight
- Reduce stress
- Get an adequate amount of sleep
- Exercise the brain (doing puzzles, quizzes, card games, reading, learning a new language or playing a new instrument)
- Engage in social activities
Most important, see your doctor every 6 to 12 months so that he or she can check for changes in your memory or thinking skills over time.
Outlook / Prognosis
What’s the outcome for people with mild cognitive impairment (MCI)?
Researchers believe that most patients with mild cognitive impairment (MCI) will go on to develop dementia. MCI is a stage between the mental decline seen in normal aging and the onset of early dementia.
It is not yet possible to know the rate of decline in a particular person with mild cognitive impairment. Researchers continue to study the mental and medical changes that occur in patients with mild cognitive impairment in the hopes of better predicting who might be at an increased risk of developing – and the speed at which they develop -- specific types of dementia.