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.

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.)

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