Maintaining Your Health on Mackinac
Alzheimer's Disease Is Most Common Form of Senile Dementia
By Yvan Silva, M.D.

In 1906, a German physician, Alois Alzheimer, described abnormal plaques and tangles in the brain of a 55-year-old woman who had died after spending the last years of her life in a mental institution. Over the years, this disease has become known as the most common form of senile dementia. In 2000, it was estimated that 20 million people were diagnosed with Alzheimer's worldwide, with approximately 4.5 million in the United States. It is a progressive condition with a decline in mental abilities such as memory, language usage, and logical thinking, which interferes with physical and social activities. It is age-related, generally manifesting in the mid60s, although it can affect people in their 40s and 50s. According to some estimates, as the population grows and people live longer, there will be a threefold rise in the number of people living with Alzheimer's by the year 2050. The average lifespan has kept increasing over the past decades to about 77, where it is today.

Many scientists believe that the main cause of the disease is linked to a protein known as beta amyloid. An increase in the amount of this protein and an abnormality that causes "stickiness" is linked to the formation of sticky plaques outside the neurons in the brain, and stringy tangles within them. These changes in the brain cause decreased activity in areas important for processing memory and language. An emerging yet controversial theory offered is that excess of beta amyloid is toxic to neurons in a similar way that cholesterol excess is damaging to the lining of blood vessels. An important focus of research is underway to test this hypothesis as well as several others, with the goals of prevention and cure.

The diagnosis of Alzheimer's is usually based on criteria developed to classify an individual as definite, probable, or possible, depending on the evaluation of clinical symptoms and other testing parameters. It is said that there is a low rate of recognition by family members and even some physicians during the early stages. It is difficult, obviously, to distinguish dementia from the mental wear and tear of normal aging. Two simple tests are available, the first a scoring test for orientation, memory, and concentration, and the second a test to score daily activities and social independence. While these initial tests are helpful, they apply to the broad area of dementia, and there are dozens of conditions that can mimic it - depression, dehydration, effects of drugs, and others. Some dementias like Alzheimer's are irreversible and diagnosis requires specific testing.

The clinical features that predominate are amnesia and memory impairment, deterioration of language abilities, visual deficits, and difficulties with spatial configuration. In the later phases of the condition, motor and sensory abnormalities ensue; there are problems with gait and loss of overall abilities for independent living. Lapses of memory and forgetfulness occur from time to time as aging continues. Symptoms of Alzheimer's vary from person to person, but they do worsen over time. There are some common characteristics. Individuals regress in the performance of normal activities such as written communications, balancing bank accounts, and use of public transport; activities such as eating, grooming, and using the toilet become increasingly difficult. Confusion, disorientation, and getting lost in familiar surroundings ensue as the process moves from mild to moderate. Behavioral changes progress over time. Mood changes and apathy usually develop early and continue; agitation and psychotic behavior are characteristic in the middle stages.

Moderate symptoms include increasing difficulties with activities of daily living, anxiety and depression, problems with sleeping, wandering, and recognizing familiar individuals, family members, and close friends. In the late stages loss of speech, inability to eat and weight loss, and loss of control over bodily functions progress to total dependence on others for daily living.

Diagnosing Alzheimer's disease begins with a detailed medical history of general health, co-morbid conditions, and risk factors pertaining to overall health - hypertension, diabetes, arthritis, and other issues usually associated with age, family history, and lifestyle. There are neuropsychological tests that help to evaluate memory, attention, problem solving, and other areas. These can sometimes be limited by the degree of dementia that might render a patient uncommunicative. A battery of tests that include blood counts, tests of thyroid function, X-rays, and scans are used when indicated.

Magnetic resonance imaging (MRI) and brain scans are used to establish if there are lesions in the brain. PET (positron emission tomography) scans show the activity of various regions of the brain. In Alzheimer's disease, activity can be decreased in areas that are important in processing memory and language.

There is no cure for Alzheimer's. There are medications that may delay progression of the disease or improve symptoms such as anxiety, sleeping difficulties, or depression. A treatment plan should be put in place with close involvement of doctors, nursing specialists, and social workers in strong alliances with family members and caregivers. There are support groups that provide practical help as well. There are practical guidelines available for caregivers in local communities to provide medical and social care for patients. The national network created by the Alzheimer's Association, Safe Return, is an important resource.

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