Overview

Mild cognitive impairment (MCI) is the stage between the expected decline in memory and thinking that happens with age and the more serious decline of dementia. MCI may include problems with memory, language or judgment.

People with MCI may be aware that their memory or mental function has "slipped." Family and close friends also may notice changes. But these changes aren't bad enough to impact daily life or affect usual activities.

MCI may increase the risk of dementia caused by Alzheimer's disease or other brain disorders. But some people with mild cognitive impairment might never get worse. And some eventually get better.

Products & Services

Symptoms

The brain, like the rest of the body, changes with age. Many people notice they become more forgetful as they age. It may take longer to think of a word or to recall a person's name.

If concerns with mental function go beyond what's expected, the symptoms may be due to mild cognitive impairment (MCI). MCI may be the cause of changes in thinking if:

  • You forget things more often.
  • You miss appointments or social events.
  • You lose your train of thought. Or you can't follow the plot of a book or movie.
  • You have trouble following a conversation.
  • You find it hard to make decisions, finish a task or follow instructions.
  • You start to have trouble finding your way around places you know well.
  • You begin to have poor judgment.
  • Your family and friends notice any of these changes.

If you have MCI, you also may experience:

  • Depression
  • Anxiety
  • A short temper and aggression
  • A lack of interest

When to see a doctor

Talk to your health care provider if you or someone close to you notices you're having problems with memory or thinking. This may include trouble recalling recent events or having trouble thinking clearly.

Causes

There's no single cause of mild cognitive impairment (MCI), although MCI may be due to early Alzheimer's disease. There's no single outcome for the disorder. Symptoms of MCI may remain stable for years. Or MCI may progress to Alzheimer's disease dementia or another type of dementia. In some cases, MCI may improve over time.

MCI often involves the same types of brain changes seen in Alzheimer's disease or other forms of dementia. In MCI, those changes occur at a lesser degree. Some of these changes have been seen in autopsy studies of people with MCI.

These changes include:

  • Clumps of beta-amyloid protein, called plaques, and tangles of tau proteins that are seen in Alzheimer's disease.
  • Microscopic clumps of a protein called Lewy bodies. These clumps are 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:

  • Decreased size of the hippocampus, a brain region important for memory.
  • Increased size of the brain's fluid-filled spaces, known as ventricles.
  • Reduced use of glucose in key brain regions. Glucose is the sugar that's the main source of energy for cells.

Risk factors

The strongest risk factors for MCI are:

  • Increasing age.
  • Having a form of a gene known as APOE e4. This gene also is linked to Alzheimer's disease. But having the gene doesn't guarantee that you'll have a decline in thinking and memory.

Other medical conditions and lifestyle factors have been linked to an increased risk of changes in thinking, including:

  • Diabetes
  • Smoking
  • High blood pressure
  • High cholesterol
  • Obesity
  • Depression
  • Obstructive sleep apnea
  • Lack of physical exercise
  • Low education level
  • Lack of mentally or socially stimulating activities

Complications

People with MCI have an increased risk — but not a certainty — of developing dementia. Overall, about 1% to 3% of older adults develop dementia every year. Studies suggest that around 10% to 15% of people with MCI go on to develop dementia each year.

Prevention

Mild cognitive impairment can't be prevented. But research has found some lifestyle factors may lower the risk of getting MCI. Studies show that these steps may help prevent MCI:

  • Don't drink large amounts of alcohol.
  • Limit exposure to air pollution.
  • Reduce your risk of a head injury.
  • Don't smoke.
  • Manage health conditions such as diabetes, high blood pressure, obesity and depression.
  • Practice good sleep hygiene and manage any sleep problems.
  • Eat a healthy diet full of nutrients. Include fruits and vegetables and foods low in saturated fats.
  • Stay social with friends and family.
  • Exercise at a moderate to vigorous intensity most days of the week.
  • Wear a hearing aid if you have hearing loss.
  • Stimulate your mind with puzzles, games and memory training.

Mild cognitive impairment (MCI) care at Mayo Clinic

Nov. 02, 2022
  1. Knopman DS, et al. Alzheimer disease. Nature Reviews. Disease Primers. 2021; doi:10.1038/s41572-021-00269-y.
  2. Jankovic J, et al., eds. Alzheimer disease and other dementias. In: Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed Sept. 21, 2022.
  3. Zhuang L, et al. Cognitive assessment tools for mild cognitive impairment screening. Journal of Neurology. 2021; doi:10.1007/s00415-019-09506-7.
  4. What is mild cognitive impairment? National Institute on Aging. https://www.nia.nih.gov/health/what-mild-cognitive-impairment. Accessed Sept. 21, 2022.
  5. Mild cognitive impairment (MCI). Alzheimer's Association. https://www.alz.org/alzheimers-dementia/what-is-dementia/related_conditions/mild-cognitive-impairment. Accessed Sept. 21, 2022.
  6. Lewis JE, et al. The effects of twenty-one nutrients and phytonutrients on cognitive function: A narrative review. Journal of Clinical and Translational Research. 2021; doi:10.18053/jctres.07.202104.014.
  7. Kellerman RD, et al. Alzheimer's disease. In: Conn's Current Therapy 2022. Elsevier; 2022. https://www.clinicalkey.com. Accessed Sept. 21, 2022.
  8. Ferri FF. Mild cognitive impairment. In: Ferri's Clinical Advisor 2023. Elsevier; 2023. https://www.clinicalkey.com. Accessed Sept. 21, 2022.
  9. Petersen RC, et al. Practice guideline update summary: Mild cognitive impairment: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Neurology. 2018; doi:10.1212/WNL.0000000000004826.
  10. Budson AE, et al. Subjective cognitive decline, mild cognitive impairment and dementia. In: Memory Loss, Alzheimer's Disease, and Dementia. 3rd ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed Sept. 21, 2022.
  11. Cognitive impairment in older adults: Screening. U.S. Preventive Services Task Force recommendation statement. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/cognitive-impairment-in-older-adults-screening. Accessed Sept. 21, 2022.
  12. Levenson JL, ed. Dementia. In: The American Psychiatric Association Publishing Textbook of Psychosomatic Medicine and Consultation-Liaison Psychiatry. 3rd ed. American Psychiatric Association Publishing; 2019. https://psychiatryonline.org. Accessed Sept. 21, 2022.
  13. Livingston G, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet. 2020; doi:10.1016/S0140-6736(20)30367-6.
  14. Abdi Beshir S, et al. Aducanumab therapy to treat Alzheimer's disease: A narrative review. International Journal of Alzheimer's Disease. 2022; doi:10.1155/2022/9343514.
  15. Memory, forgetfulness and aging: What's normal and what's not? National Institute on Aging. https://www.nia.nih.gov/health/memory-forgetfulness-and-aging-whats-normal-and-whats-not. Accessed Sept. 26, 2022.
  16. Ami T. Allscripts EPSi. Mayo Clinic. April 21, 2022.
  17. Alzheimer's disease research centers. National Institute on Aging. https://www.nia.nih.gov/health/alzheimers-disease-research-centers#minnesota. Accessed Sept. 26, 2022.
  18. About the Alzheimer's Consortium. Arizona Alzheimer's Consortium. https://azalz.org/about/#institutes. Accessed Sept. 26, 2022.
  19. Aducanumab approved for treatment of Alzheimer's disease. Alzheimer's Association. https://www.alz.org/alzheimers-dementia/treatments/aducanumab. Accessed Sept. 28, 2022.
  20. Graff-Radford J (expert opinion). Mayo Clinic. Sept. 30, 2022.
  21. Shi M, et al. Impact of anti-amyloid-β monoclonal antibodies on the pathology and clinical profile of Alzheimer's disease: A focus on aducanumab and lecanemab. Frontiers in Aging and Neuroscience. 2022; doi:10.3389/fnagi.2022.870517.
  22. Cummings J, et al. Alzheimer's disease drug development pipeline: 2022. Alzheimer's and Dementia. 2022; doi:10.1002/trc2.12295.