Trends in aging: Alzheimer's and Dementia Part 1: Dementia

By Wendy McHaney
Sept. 27, 2013 at 4:27 a.m.

Wendy McHaney

Wendy McHaney

This next series of columns focuses on dementia, primarily Alzheimer's disease. Dementia is a general term for memory loss and other mental abilities severe enough to interfere with daily life.

Dementia is not a specific disease and is rather an overall term to describe a wide range of symptoms associated with a decline in memory or other thinking skills.

It is caused by permanent damage or death of the brain's nerve cells, which interferes with the cells' ability to communicate with each other.

The brain has many distinct regions, each being responsible for different functions such as memory, judgment and movement.

When cells in a particular region are damaged, that region cannot carry out functions normally.

Alzheimer's disease is the most common cause of dementia in people over the age of 65, and represents about 60 percent of all dementias.

Because of the complexity and prevalence of Alzheimer's disease, I plan to dedicate several columns to the disease. Therefore this first column will focus on the other types of dementia.

Vascular dementia is the second most common cause of dementia after Alzheimer's disease. This type of dementia usually occurs because of brain injuries, such as microscopic bleeding and blood vessel blockage. Impaired judgment or ability to plan steps needed to complete a task is more likely to be the initial symptom, as opposed to the memory loss of Alzheimer's.

Another type of dementia is Lewy bodies, and people with this disease often have memory loss and thinking problems common in Alzheimer's, but are more likely than people with Alzheimer's to have initial or early symptoms, such as sleep disturbances, visual hallucinations, muscle rigidity or other muscle movement features similar to Parkinson's disease.

Parkinson's disease dementia is a decline in thinking and reasoning that can develop at least a year after being diagnosed with the disease. Symptoms include changes in memory, concentration and judgment, and trouble interpreting visual information. An estimated 50-80 percent of those with Parkinson's eventually experience dementia as their disease progresses.

Frontotemporal dementia is characterized by changes in personality and behavior and difficulty with language. Nerve cells in the front and side regions of the brain are especially affected.

Huntington's Disease is a progressive brain disorder caused by a single defective gene on chromosome 4. Symptoms include abnormal involuntary movements, a severe decline in thinking and reasoning skills and mood changes such as irritability or depression.

Mixed dementia is characterized by the hallmark abnormalities of more than one type of dementia, the most common being a mix of Alzheimer's and vascular dementia.

Recent studies suggest that mixed dementia is more common than previously thought.

SOURCE: Alzheimer's Association, Alzheimer's Foundation of America

Wendy McHaney is a certified senior adviser and the owner and director of operations of Senior Helpers. For more information about Senior Helpers, visit



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