Mild Cognitive Impairment
- Mild cognitive impairment (MCI) is defined as significant cognitive impairment in the absence of dementia, as measured by standard memory tests:
- Concern regarding change in cognition
- Preservation of independence in functional activities (ADLs)
- Impairment in ≥1 cognitive domains (attention, executive dysfunction, memory, visuospatial, language)
- Other terms used in the literature relating to MCI: cognitive impairment not dementia (CIND); mild cognitive disorder. Some of these conditions do not progress to dementia. DSM-5 mentions “mild neurocognitive disorder” (mNCD), which may be a precursor to Alzheimer disease and has many of the same features as MCI.
- Predominant sex: male > female
- Predominant age:
- Higher in older persons and in those with less education
- 12 to 15/1,000 person-years in those aged ≥65 years
- 50 to 75/1,000 person-years in those aged ≥75 years
- MCI is more prevalent than dementia in the United States.
- 12–18% for those aged ≥60 years; ~25% for ages 80 to 84 years; prevalence increases with age and for those with lower educational level (2).
Etiology and Pathophysiology
- Subtypes of MCI:
- Single-domain amnestic
- Multiple-domain amnestic
- Single-domain nonamnestic
- Multiple-domain nonamnestic
- The amnestic subtypes are higher risk for progression to Alzheimer disease.
- Vascular, neurodegenerative, traumatic, metabolic, psychiatric, or a combination
In certain subsets of MCI where the disease will progress to Alzheimer disease, one must consider apolipoprotein (APO) E4 genotype: Various pathways exist leading to amyloid accumulation and deposition thought to be associated with Alzheimer disease.
- Diabetes; hypertension; hyperlipidemia; cerebrovascular disease
- Sleep apnea
- APO E4 genotype
- Low educational levels
- Sedentary lifestyle
Optimize vascular risk factors and focus on a healthy, active lifestyle.
Commonly Associated Conditions
See “Risk Factors.”
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