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Conditions

Mild cognitive impairment (MCI)

An intermediate state between normal and dementia — risk is raised, but independence is preserved

A fork in the road between a healthy brain and a brain showing signs of dementia

Mild cognitive impairment (MCI) is an intermediate state between normal age-related decline and dementia. A decline in memory or thinking is already noticeable and confirmed by tests, but the person retains independence in daily life.

How it differs from dementia

The key difference is independence. In MCI there are complaints about memory or thinking and an objective decline on testing, but the person still manages everyday tasks. In dementia the impairment already interferes with independent living. MCI is not an inevitable sentence: the condition can stay stable for years.

Types and prognosis

An amnestic type is distinguished (memory is affected first — a higher risk of progression to Alzheimer’s disease) and a non-amnestic type. The impairment may involve one or several domains; involvement of several domains means a greater risk of progression. On average about 10–15% of people with MCI progress to dementia per year, but about half do not progress over 5 years, and some return to normal.

Causes and what to do

MCI may be driven by early neurodegeneration or vascular damage, but there are also reversible causes: vitamin B12 deficiency, hypothyroidism, depression, sleep disorders, drug side effects. That is why a work-up matters. Controlling vascular factors, physical activity, and mental and social engagement all help.

Calculate using this marker

Calculators where Mild cognitive impairment (MCI) is used directly:

Cognitive Age 20 questions on memory, thinking speed, and mental flexibility — your cognitive age in 5 minutes Open Mental Age 12 questions on emotion, openness, and maturity — the age of your mind across five personality dimensions Open

Frequently asked questions

Does MCI always progress to dementia?

No. On average about 10–15% progress per year, but roughly half of people do not progress to dementia over 5 years, and some even return to normal scores, especially if the cause is reversible.

Which causes of MCI are reversible?

Vitamin B12 deficiency, reduced thyroid function, depression, sleep disorders (including apnea) and the side effects of some drugs. Detecting and correcting them can improve cognition.

Related terms

Dementia A progressive decline in cognitive function that disrupts daily life. Alzheimer's disease A neurodegenerative disease — the most common cause of dementia. Cognitive aging Age-related changes in memory, thinking speed and concentration — normal, not a disease Cognitive age The brain's age from memory, thinking speed and flexibility Neurodegeneration The progressive death of neurons — the basis of Alzheimer's, Parkinson's and dementias Vitamin B12 (cobalamin) A water-soluble vitamin for DNA synthesis, nervous-system function and blood formation. It is stored in the liver, with reserves lasting 3–5 years. Homocysteine A sulfur-containing amino acid — a marker of the risk of heart attack, stroke and dementia. It rises with a deficiency of B12, B9 or B6.

Sources

  1. Classification and Epidemiology of MCI (PMC)
  2. MCI: searching for the prodrome of Alzheimer’s disease (PMC)
info
This content is educational and does not replace consultation with a physician. Reference ranges may vary depending on the laboratory and method — rely on the ranges stated on your own test report.
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