Dementia Is Defined by Loss of ‘Thinking’ Brain Functions
Maintaining Your Health
on Mackinac
By Yvan Silva, M.D.

Dementia is defined by the loss of intellectual ability; the losses of cognitive or “thinking” function. Dementia is not necessarily a normal progression of aging, although it is more common in older adults. Persons with dementia exhibit changes, especially to those familiar with them, confusion, lack of ability to remember things or where they placed them; they begin to deteriorate in their skills to perform activities of daily living. There are several causes of dementia and it is important to differentiate the diagnosis of cause to effectively manage care.

Memory loss is well known to be associated with growing older. In dementia the loss of memory increases progressively. It may be gradual, but it does increase continuingly. Thinking becomes unclear or even irrational and there is a loss of problem solving skills. Confusion is an important sign. People who suffer with dementia lose their interest in daily personal and social activities; they often exhibit behavioral changes such as anger, agitation, and delusion. Becoming lost in usually familiar surroundings frequently leads to concerns by family members and friends.

Dementia results from changes in the brain that prevent normal transmission within the central nervous system and higher functions that direct thinking and decision making. The most common cause is Alzheimer’s disease. Nerve cells, neurons that promulgate cognitive function and memory, become damaged. The cause is not exactly known but abnormal proteins begin to build up in some areas of the brain. Tiny protein plaques and fibrous tangles are found in the brain on microscopic examination. Changes are also observed in the whole brain, which diminishes in size, usually by about 15 percent in volume. Because this disease is familial, it is important for family members to obtain autopsy confirmation in appropriate circumstances. Again, Alzheimer’s disease affects older individuals, but sometimes it can begin in younger adults. Known risk factors for this disease include family history and advancing age.

Dementia can ensue and progress as a result of very small strokes that deprive the brain of blood flow, especially to those areas responsible for memory and thinking. This is known as vascular dementia, and the strokes result from tiny blood clots in the circulation of the brain, or areas of bleeding that stay contained and damage brain cells. Brain tissues can be affected by abnormal neurological processes, such as Parkinson’s disease that causes tremors and muscle stiffness, and Huntington’s disease, an inherited disease that causes abnormal movements and dementia. Although less common, infections of the brain and central nervous system can cause dementia, like HIV, the human immunodeficiency virus that causes AIDS, syphilis, tuberculosis, or bacterial or viral meningitis, infections of the brain covering tissues, or encephalitis, infections of the brain tissue.

It is important to get a detailed, comprehensive evaluation when a person begins to exhibit symptoms of dementia. A careful review of the onset and progression, the general health of the individual, and a thorough physical examination is a good start. Ancillary laboratory and radiographic tests to identify possible reversible causes, such as infection, are indicated. There is no cure for Alzheimer’s disease or vascular dementia.

There are several promising lines of research into causes and treatment, including possible vaccines underway for Alzheimer’s. Attention to cardiovascular health for family members of patients with vascular dementia is important for their individual benefits.

Prescription medications are now available that may help to slow the progress of dementia. There is mounting evidence that physical activity may be related to the onset and progression of dementia. In two studies, one in men 71 to 93 years of age, and one in women aged 70 to 81 years, it was shown that long-term physical activity, including walking, was associated with a reduced risk of dementia. Better maintenance of cognitive function and a lesser decline was observed in both men and women in these age groups. This adds to our knowledge that regular physical activity included in our lifestyles, including the elderly, is beneficial.

Dr. Silva is a professor of surgery at Wayne State University and a resident of Woodbluff on Mackinac Island.