Which disorders are associated with mild cognitive impairment (MCI)?

Updated: Apr 22, 2019
  • Author: Sonal Mehta, MD; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Answer

Answer

Mild cognitive impairment (MCI) may result from virtually any disorder that causes brain dysfunction. Common causes include the following:

  • Alzheimer disease (AD)

  • Cerebrovascular disease

  • Parkinson disease

  • Frontotemporal degenerations

  • Thyroid disease

  • HIV infection

  • Depression

  • Metabolic and endocrine disease [26]

  • Adverse central nervous system effects of drugs and toxicants

  • Cerebral infection

  • Traumatic brain injury

  • Cognitive adverse effects of sleep disorders

  • Cobalamin deficiency

  • Chronic psychological stress

According to an analysis of 5150 patients aged 65 years or older from the Cardiovascular Health Study, patients with atrial fibrillation (AF) reach clinical thresholds for cognitive impairment and dementia at an earlier age than patients without AF, even in the absence of clinical stroke. [27, 28]

Depressive disorders are particularly prevalent in older adults (approximately 15%), who frequently exhibit vague somatic symptoms and anxiety and report inability to concentrate and poor memory. These patients typically deny a sad mood but often admit to sleep symptoms, lack of interest in things they used to enjoy, loss of appetite, and lack of motivation. Depression may certainly be accompanied by cognitive dysfunction that abates with successful treatment of the depression.

The association between depression and AD and other dementias is likely to be complex, and depression may be misdiagnosed in the realm of dementia. Framingham data have helped bolster the epidemiologic association, documenting a 50% increase in AD and dementia in those who were depressed at baseline. [29] During a 17-year follow-up period, a total of 21.6% of participants who were depressed at baseline developed dementia, compared with 16.6% of those who were not depressed.

In another related study, recurrent depression was noted to be particularly pernicious: having 1 depression episode conferred an 87-92% increase in dementia risk, whereas having 2 or more episodes nearly doubled the dementia risk (but did not increase the risk of incident MCI). [30]


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