Ten to 20 percent of adults 65 and better are diagnosed with mild cognitive impairment (MCI), and risk for this condition increases with age. MCI is also associated with a greater risk of dementia, although dementia is not inevitable for those diagnosed with MCI. Recently the Journal of the American Medical Association conducted a review of the literature in order to provide recommendations for how to best manage this condition.
MCI is defined as a pre-dementia stage on the continuum of cognitive decline, in which an individual has an objective impairment in cognition that is not severe enough to require help with activities of daily living (ADLs). The main criteria distinguishing MCI from dementia is this preservation of independence, and a lack of social or occupational impairment among individuals with MCI.
As with dementia, there are multiple potential causes for MCI. These include Alzheimer’s Disease, but other conditions such as cerebrovascular disease, infections, or vitamin deficiencies can produce MCI as well. The risk of MCI increases with age, and is higher in men than women. Additional risk factors for MCI include lower educational levels, vascular risk factors such as diabetes or high blood pressure, vitamin D deficiency, and sleep-disordered breathing. Depression is also associated with cognitive impairment, and this is likely bidirectional, with depression leading to greater risk of cognitive decline and cognitive decline leading to greater risk of depression.
About nine percent of cases of MCI are reversible, so an individual with MCI should undergo laboratory tests to identify whether the cause of their MCI is reversible (such as infection, kidney failure, hyperglycemia, vitamin B12 or folate deficiency, or hypothyroidism). Of those cases that are not reversible, individuals with MCI need to be informed that only a minority of individuals with MCI will progress to dementia annually. Even after 10 years, between 40 and 70 percent of individuals may not progress to dementia. And between 15 and 20 percent of individuals diagnosed with MCI will have improved cognition one to two years later (although still qualifying for an MCI diagnosis).
Even though many forms of MCI are not reversible, steps can be taken to reduce the risk of MCI progressing to dementia and possibly bring about cognitive improvements. One such step is to focus on reducing risk factors associated with stroke prevention and cardiovascular conditions, such as activities and treatments associated with better heart health, including managing blood pressure and treating diabetes. However, the article also cautions against over-treating blood pressure and diabetes, since hypoglycemia and hypotension are also associated with cognitive decline. In addition to medical treatment related to vascular health, there are a number of beneficial behaviors related to both better vascular and cognitive outcomes, including engaging in physical and mental activity, as well as cessation of smoking, heavy drinking, and illicit drug use. In terms of physical activity, both aerobic and strength training have been shown to provide benefit. The paper also recommends encouraging social engagement, which has been associated with the preservation of memory and lower risk of cognitive decline. Poor vision and hearing are also associated with cognitive decline, so these should be checked as well. Finally, individuals with MCI are at greater risk of falls, so extra attention should be paid to gait and mobility.
MCI should not be assumed to lead to an eventual, inevitable dementia diagnosis. While it carries an increased risk of dementia, an important element of managing MCI is taking steps that can reduce that risk of developing dementia, and this message should also be a part of counseling and discussions surrounding this frightening medical condition.
Langa KM and Levine DA. The diagnosis and management of mild cognitive impairment: a clinical review. JAMA (2014); 312(23): 2551–2561.