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Dealing with Dementia: When Thinking and Behavior Decline

NIH | Jan 16, 2015, noon

Forgetfulness, confusion, or having trouble remembering a name or word can be a normal part of life. But when thinking problems or unusual behavior starts to interfere with everyday activities—such as working, preparing meals, or handling finances—it’s time to see a doctor. These could be signs of a condition known as dementia.

Dementia is a brain disorder that most often affects the elderly. It’s caused by the failure or death of nerve cells in the brain. By some estimates, up to half of people ages 85 and older may have Alzheimer’s disease, the most common cause of dementia. Although age is the greatest risk factor for dementia, it isn’t a normal part of aging. Some people live into their 90s and beyond with no signs of dementia at all.

“Dementia really isn’t a disease itself. Instead, dementia is a group of symptoms that can be caused by many different diseases,” says Dr. Sanjay Asthana, who heads an NIH-supported Alzheimer’s disease center at the University of Wisconsin. “Symptoms of dementia can include problems with memory, thinking, and language, along with impairments to social skills and some behavioral symptoms.”

Several factors can raise your risk for developing dementia. These include aging, smoking, uncontrolled diabetes, high blood pressure, and drinking too much alcohol. Risk also increases if your family members have had dementia.

Dementia can be reversed when it’s caused by dehydration or other treatable conditions. But most forms of dementia worsen gradually over time and can’t be corrected. Scientists are searching for ways to slow down this process or prevent it from starting in the first place.

The 2 most common causes of dementia in older people are Alzheimer’s disease and vascular dementia, a condition that involves changes to the brain’s blood supply. Vascular dementia often arises from stroke or arteriosclerosis (hardening of the arteries) in the brain. Other causes of dementia include Parkinson’s disease, HIV infection, head injury, and Lewy body disease. (Lewy bodies are abnormal protein clumps in brain cells.)

Dementia in people under age 60 is often caused by a group of brain diseases called frontotemporal disorders. These conditions begin in the front or sides of the brain and gradually spread. A rare, inherited form of Alzheimer’s disease can also occur in people in their 30s, 40s, and 50s.

The symptoms of dementia can vary, depending on which brain regions are damaged. “In general, the left side of the brain is involved in language, and the right side is very involved in social behavior,” says Dr. Bruce L. Miller, who directs an NIH-funded dementia center at the University of California, San Francisco.

In the case of a frontotemporal disorder, “if it begins in the left side of the brain, you tend to have worsening language problems; if it starts on the right, it affects behavior and might be mistaken for a psychiatric condition,” Miller explains. Damage to particular left brain regions can cause people to become apathetic, lose their inhibitions, or show no consideration for the feelings of others.

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