Mild Cognitive Impairment – a subtle but detectable memory disorder -- falls in-between everyday forgetfulness and dementia.
People can expect a certain degree of forgetfulness with age. While frustrating, there is no indication that such normal memory lapses will eventually lead to Alzheimer’s disease. But new evidence suggests that more persistent memory problems may be a reason for concern. The disturbances fall somewhere in-between age-associated memory impairment (AAMI) and early dementia.
Known as mild cognitive impairment (MCI), kind of memory loss causes patients to forget more than is normal for their age, but they do not exhibit the same cognitive problems associated with dementia, such as feeling disoriented or confused about routine activities.
Some experts contend that this transitional state may be an early warning sign for memory disorders later in life. In fact, studies show that 10 to 12% of patients with mild cognitive impairment progress to Alzheimer’s disease each year, compared to a rate of 1 to 2% a year for the general population.
What Is Mild Cognitive Impairment?
Misplacing your car keys or occasionally forgetting a name is by no means unusual. But individuals with mild cognitive impairment are likely to forget important information on a regular basis. Often, they may want to remember something, but can’t. When compared to people of their same age, those with mild cognitive impairment have greater difficulty remembering as many details, and usually forget things repeatedly. For example, they may ask a person the same question over and over again, only to keep forgetting the answer.
These kinds of memory problems are often apparent to family and friends, who may become concerned that the person is suffering from Alzheimer’s disease. Patients with dementia, however, have other symptoms in addition to memory problems, such as becoming disoriented. People with mild cognitive impairment are generally able to live independently but may be less active socially.
Who Is at Risk for Mild Cognitive Impairment?
Researchers from a number of institutions, including Johns Hopkins, have studied a group of 3,608 people, age 65 and older, and periodically looked for signs of memory impairment through the better part of a decade. Overall, 19% of people in this age group developed mild cognitive impairment during the study, the researchers reported in the Archives of Neurology.
Typically, experts have considered mild cognitive impairment a condition that affects mainly memory but not other aspects of cognition, such as attention, concentration, visuospatial skills, or language. However, the investigators in the Archives study found that people with mild cognitive impairment had a high likelihood of having deficits in other cognitive areas in addition to memory, which could have affected how well they were able to perform daily functions, such as balancing a checkbook.
In a second study in the same publication, the same authors found that many of the demographic and genetic characteristics associated with mild cognitive impairment are the same as those for Alzheimer’s disease. These include being older, being African-American, and having low levels of education (high school or less).
Also, some medical conditions and procedures, particularly those that involve the heart and blood vessels, are more prevalent in the mild cognitive impairment population than in people without mild cognitive impairment. Compared to people without mild cognitive impairment, those with the condition showed a greater prevalence of high blood pressure, depression, heart disease, diabetes, and stroke than people without this form of dementia.
Is Mild Cognitive Impairment Treatable?
By intervening at the first signs of memory trouble, researchers hope to delay Alzheimer’s disease, or prevent it altogether. Large-scale studies are underway to test whether therapies can halt or slow the conversion from mild cognitive impairment to Alzheimer’s disease.
However, one such study, presented at the 9th International Conference on Alzheimer’s Disease and Related Disorders, did not show a significant benefit for vitamin E or Aricept (donepezil) in slowing the development of Alzheimer’s disease in people with mild cognitive impairment. Although after 18 months of treatment, patients who took Aricept had a delayed progression to Alzheimer’s disease compared with those who took a placebo, by three years, people with mild cognitive impairment who took Aricept, vitamin E, or a placebo ultimately all progressed to Alzheimer’s disease at the same rate.
The Bottom Line on Mild Cognitive Impairment
People who are having a much harder time than usual remembering important information should consult a doctor, since these problems could signal dementia or an underlying medical condition. A diagnosis of mild cognitive impairment will at least confirm that memory problems are not the result of other causes. Routine screening for mild cognitive impairment is not recommended at this time, since there is no proven way to treat the condition or prevent further memory decline. Although mild cognitive impairment appears to increase the chances of future memory disorders, patients should keep in mind that many people with this condition do not progress to Alzheimer’s disease.
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Posted in Memory on April 6, 2006
Reviewed June 2008
