People with mild cognitive impairment are more forgetful than normal for their age, but they don’t experience other cognitive problems associated with dementia, such as disorientation or confusion about routine activities.
Routine tasks such as paying bills, shopping, and meal preparation may become challenging. People with mild cognitive impairment may take more time doing these things and they may make more mistakes. They are generally able to live independently but may be less active socially.
About one in five older adults has some type of mild cognitive impairment. In a 2010 study of nearly 2,000 people, about 16 percent of dementia-free people over age 70 were suffering from mild cognitive impairment. Men were more likely to suffer than women, although women may simply experience dementia at a later age. In the study, risk factors included being a carrier of the APOE e4 gene (a known risk factor for late-onset Alzheimer’s disease), never having married, and having less than nine years of education.
In a 2011 study of nearly 1,300 women age 85 and older, 23 percent were diagnosed with mild cognitive impairment. The researchers recommend that women this age should be screened for cognitive problems.
The National Institute on Aging-Alzheimer’s Association workgroup has come up with new diagnostic guidelines for mild cognitive impairment due to Alzheimer’s disease. With mild cognitive impairment, people experience gradual cognitive decline due to Alzheimer’s-related brain changes.
What to look for
A person is thought to suffer from mild cognitive impairment if he or she meets the following criteria:
• A friend, family member, doctor, or the person in question is concerned about a change in his or her cognition compared to the previous level.
• The person is experiencing more difficulties in one or more cognitive areas such as memory, attention, and language than would be expected for his or her age or educational background. Difficulty learning and retaining new information is most common in mild cognitive impairment patients who develop Alzheimer’s-related dementia.
• The person is having trouble performing complex tasks such as paying bills, preparing a meal, or shopping. He or she may take more time, be less efficient, and make more mistakes than in the past. Still, he or she maintains his or her independence with minimal assistance.
• There’s no evidence of significant impairment in social or occupational functioning.
• There should be objective evidence of progressive cognitive decline over time. Cognitive testing can assess the degree of impairment. Scores for people with mild cognitive impairment are usually 1 to 1.5 standard deviations below the mean for their age and education level.
Some formal cognitive tests that assess both immediate and delayed recall can help identify mild cognitive impairment patients who are likely to progress to Alzheimer’s dementia within a few years. They include the Free and Cued Selective Reminding Test, the Rev Auditory Verbal Learning Test and the California Verbal Learning Test.
Other tests can determine impairment in problem-solving, reasoning and language. Doctors may also assess a person’s cognitive function using informal techniques, like asking a patient to learn a street address and then remember it after a delay.
• Vascular, traumatic, and medical illnesses that could explain the decline in cognition must be ruled out. The goal is to increase the likelihood that the underlying cause of mild cognitive impairment is probably Alzheimer’s.
• If a person is known to carry a genetic defect, such as a mutation in APP, PS1 or PS2, he or she is most likely suffering from mild cognitive impairment due to Alzheimer’s disease. Most of these carriers develop Alzheimer’s before age 65. A person who meets the diagnostic criteria for mild cognitive impairment and carries the apolipoprotein E gene is more likely to progress to Alzheimer’s dementia within a few years than someone without this gene.
Biomarkers—such as proteins that can be measured in spinal fluid as well as imaging tests like positron-emission tomography (PET) scans—are being studied or used to increase accuracy in diagnosing mild cognitive impairment.
Doctors are looking for specific proteins—beta-amyloid and tau—which are found in the brain of a person affected by Alzheimer’s disease. Identifying these proteins could help doctors pinpoint the underlying cause of mild cognitive impairment, which could lead to the best treatment and determine whether a person will progress to a more severe stage of mild cognitive impairment or dementia.
What may help
Researchers have discovered that activities such as exercise and computer use may prevent mild cognitive impairment. In a 2010 Mayo Clinic study, adults between ages 70 and 90 who participated in moderate physical exercise like brisk walking or biking and used a computer were less likely to develop mild cognitive impairment.
Another Mayo Clinic study found that consuming more heart-healthy mono- and polyunsaturated fats reduced the risk of mild cognitive impairment among people age 70 and older. These fatty acids—which are found in olive oil, nuts, seafood, and vegetable oils—appear to prevent inflammation and reduce the risk of blood clots, stroke, and heart disease.
Many experts believe that mild cognitive impairment may be an early warning sign of memory disorders later in life. Studies show that up to 15 percent of people with mild cognitive impairment progress to Alzheimer’s disease each year, compared with a rate of 1 to 2 percent a year for the general older population.
Large-scale studies are testing whether therapies can halt or slow the conversion from mild cognitive impairment to Alzheimer’s disease. By intervening at the first signs of memory trouble, doctors hope to delay Alzheimer’s disease, or prevent it altogether.
In a study published in Neurology, moderate drinking—defined as up to one drink per day (mostly wine)—slowed the rate of progression from mild cognitive impairment to dementia by 85 percent compared with those who abstained from alcohol.
Research on medications for staving off dementia has been discouraging, though. For example, in a recent study of people with mild cognitive impairment, researchers found no significant benefit from early intervention with the Alzheimer’s drug donepezil (Aricept) or vitamin E.