Mild cognitive impairment (MCI) is a condition in which people have more memory or other thinking problems than normal for their age, but their symptoms do not cause disability. Older people with MCI are at greater risk for developing dementia caused by Alzheimer’s, but not all of them do. Some may even go back to normal cognition. Studies are underway to learn why some people with MCI progress to Alzheimer’s dementia and others do not.
The problems associated with MCI may also be caused by certain medications, cerebrovascular disease (which affects blood vessels that supply the brain), and other factors, including depression or anxiety. Some of the problems brought on by these conditions can be managed or reversed through treatment at places like the Penn Memory Center.
The type of MCI with memory loss as the main symptom is called amnestic MCI. In another type, non-amnestic MCI, the main symptom is an impaired thinking skill other than memory loss, such as trouble planning and organizing or poor judgment.
Dementia is the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities to such an extent that it causes disability, meaning, it interferes with a person’s daily life and activities. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a person’s functioning, to the most severe stage, when the person must depend completely on others for basic activities of daily living.
Many conditions and diseases cause dementia. The most common cause of dementia in older people is Alzheimer’s disease. Other causes include different kinds of brain changes that lead to vascular dementia, Lewy body dementia, and frontotemporal disorders.
In addition, some people have mixed dementia—a combination of two or more disorders, at least one of which is dementia. A number of combinations are possible. For example, some people have Alzheimer’s disease and vascular dementia at the same time.
Alzheimer’s disease is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. In most people with Alzheimer’s, symptoms first appear in their mid-60s. Alzheimer’s disease is the most common cause of dementia and MCI among older adults.
The disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. Her symptoms included memory loss, language problems, and unpredictable behavior. After she died, he examined her brain and found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary, or tau, tangles).
These plaques and tangles in the brain are still considered some of the main features of Alzheimer’s disease. Another feature is the loss of connections between nerve cells (neurons) in the brain. Neurons transmit messages between different parts of the brain, and from the brain to muscles and organs in the body.
Although treatment can help manage symptoms in some people, currently there is no cure for this devastating disease.