About Alzheimer's Disease: Other Dementias

• What is dementia?
• Vascular Dementia
• Lewy Body Disease
• Frontotemporal Disorders

What is dementia?

Dementia is the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities to such an extent that 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. Two of the most common causes of dementia in older people are Alzheimer’s disease and vascular dementia. Others include frontotemporal dementia and other frontotemporal disorders and Lewy body disease.

Vascular Dementia

Vascular dementia, considered the second most common form of dementia after Alzheimer’s disease, results from interrupted blood flow to the brain, often after a stroke or series of strokes. The symptoms can be similar to those of Alzheimer’s, and both conditions can occur at the same time (called mixed dementia). A common type of vascular dementia is multi-infarct dementia, caused by a series of small strokes.

Recent research has shown that Alzheimer's and vascular disease-associated cognitive impairment are closely intertwined. For example, a large proportion of people diagnosed with Alzheimer's also have brain damage due to vascular disease. In addition, several studies have found that many of the major risk factors for vascular disease may also be risk factors for Alzheimer's. The overlap between the two may be important because drugs and lifestyle modifications known to be effective in preventing vascular disease, such as controlling high blood pressure, lowering cholesterol, and engaging in physical activity, may also help prevent Alzheimer's disease.

See also: Vascular Dementia: A Resource List

Lewy Body Disease

Lewy body disease is another common cause of dementia in older people. Lewy body disease happens when abnormal structures (microscopic deposits, or lesions, of abnormally aggregated proteins), called Lewy bodies, build up in areas of the brain. The disease may cause a wide range of symptoms, including: changes in alertness and attention, hallucinations, problems with movement and posture, muscle stiffness, confusion, and loss of memory.

Lewy body disease can be hard to diagnose, because Parkinson's disease and Alzheimer's disease cause similar symptoms. Scientists think that Lewy body disease might be related to these diseases, or that they sometimes happen together.

For more information, see the National Institute of Neurological Disorders and Stroke Dementia with Lewy Bodies Information Page.

Frontotemporal Disorders

Frontotemporal disorders are a form of dementia caused by a family of brain diseases known as frontotemporal lobar degeneration (FTLD). These disorders are the result of damage to neurons (nerve cells) in parts of the brain called the frontal and temporal lobes. As neurons die in the frontal and temporal regions, these lobes atrophy, or shrink. Gradually, this damage causes difficulties in thinking and behaviors controlled by these parts of the brain. Many possible symptoms can result, including strange behaviors, emotional problems, trouble communicating, or difficulty with walking and other basic movements.

Frontotemporal disorders can be grouped into three types, defined by the earliest symptoms physicians identify when they examine patients.

• Progressive behavior/personality decline—characterized by changes in personality, behavior, emotions, and judgment (e.g., behavioral variant frontotemporal dementia).
• Progressive language decline—marked by early changes in language ability, including speaking, understanding, reading, and writing (e.g., primary progressive aphasia).
• Progressive motor decline—characterized by various difficulties with physical movement, including shaking, difficulty walking, frequent falls, and poor coordination.

See:  Frontotemporal Disorders: Information for Patients, Families, and Caregivers and Frontotemporal Disorders: A Resource List