CausesBy Mayo Clinic staff
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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
- McDade EM, et al. Mild cognitive impairment: Epidemiology, pathology, and clinical assessment. http://www.uptodate.com/index. Accessed June 12, 2012.
- McDade EM, et al. Mild cognitive impairment: Prognosis and treatment. http://www.uptodate.com/index. Accessed June 12, 2012.
- Petersen RC. Mild cognitive impairment. The New England Journal of Medicine. 2011;364:2227.
- Shadlen MF, et al. Evaluation of cognitive impairment and dementia. http://www.uptodate.com/index. Accessed June 12, 2012.
- Petersen RC, et al. Mild cognitive impairment: Ten years later. Archives of Neurology. 2009;66:1447.
- Preventing Alzheimer's disease and cognitive decline. National Institutes of Health State-of-the-Science Conference Statement. April 26-28, 2010. http://consensus.nih.gov/2010/docs/alz/ALZ_Final_Statement.pdf. Accessed June 12, 2012.
- Geda YE, et al. Computer activities, physical exercise, aging, and mild cognitive impairment: A population-based study. Mayo Clinic Proceedings. 2012;87:437.
- Press D, et al. Prevention of dementia. http://www.uptodate.com/index. Accessed June 12, 2012.
- Essentials of a diagnostic work-up. Alzheimer's Association. http://www.alz.org/professionals_and_researchers_14902.asp. June 14, 2012.
- What is sleep apnea? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/sleepapnea. Accessed June 14, 2012.
- Ahlskog JE, et al. Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging. Mayo Clinic Proceedings. 2011;86:876.