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About Alzheimer’s Disease: Facts, Symptoms and Risk
Factors
What is Alzheimer’s disease?
Alzheimer’s disease is a progressive brain disorder that gradually destroys a person’s memory and ability to learn, reason, make judgments, communicate and carry out daily activities. As the disease progresses, individuals experience changes in personality and behavior. Although there is currently no cure for Alzheimer’s, new treatments are on the horizon.
Alzheimer’s disease advances at widely different rates with the duration of the illness often varying from three to 20 years. The areas of the brain that control memory and thinking skills are affected first. As the disease progresses, cells in other regions of the brain die as well. Eventually, complete care of the person with Alzheimer’s will be needed.
Are memory-loss complaints a sign of Alzheimer’s?
It is estimated that 10 million people per year in the U.S. alone visit their primary care physician with complaints about loss of memory or impaired memory. Early Alzheimer’s disease is a major contributor to memory decline in otherwise healthy and non-demented elderly persons. However, age-associated memory impairment is a decline in short-term memory that sometimes accompanies aging. It does not progress to other cognitive impairments as Alzheimer’s does.
Currently, various tests are used to distinguish memory impairment due to aging from mild cognitive impairment and memory deficits of early Alzheimer’s. Patients with Alzheimer’s disease can retain motor-type procedural memory. The selective impairment of episodic memory before the diagnosis of Alzheimer’s is consistent with the view that early changes in the hippocampal complex play an important role in the memory deficit in preclinical Alzheimer’s.
Why is early detection important?
In its early stages, it can be difficult to distinguish Alzheimer’s disease from mild cognitive impairment (MCI). MCI has evolved in recognition of the fact that measurable memory deficits, more severe than can be accounted for by simple aging, are identified without functional decline sufficient for a diagnosis of dementia. MCI is quite frequent. Nearly one in four persons over 65 years of age in the U.S. has some degree of cognitive impairment, not including elderly persons with dementia.
Furthermore, the prevalence of non-dementia cognitive impairment increased with age, from 19.2 percent for people 65 to 74 years of age to 38 percent for people 85 years of age and older. More than 80 percent of patients with MCI develop Alzheimer’s within 10 years at a rate of about 10 to 15 percent of patients per year. Upon autopsy of the brains of those diagnosed with MCI, over half were found to have Alzheimer’s, a third had evidence of cerebral infarcts and less than one-fourth showed no signs of either disease.
All current treatments, as well as most emerging ones, can only delay the onset or slow the progression of Alzheimer’s disease. Accordingly, early diagnosis is critical to extending a patient’s quality of life. Diagnosis at or before the first symptoms can add years to patients’ functional, non-impaired lives, allowing them to attend family weddings, see the births of grandchildren, or simply put their affairs in order while cognitively intact. Unfortunately, definitive methods for Alzheimer’s diagnosis have remained elusive.
How many people are at risk for Alzheimer’s?
According to the 2004 Revision of the World Population Prospects from the Department of Economic and Social Affairs of the United Nations, the number of people in the U.S. over the age of 60 was nearly 50 million in 2005. This number is expected to reach more than 104 million by 2050, while globally, the number of people 60 and older will increase from around 672 million in 2005 to around 1.9 billion by 2050.
It is well known that a great majority of AD cases develop in people over 60, with more than 90 percent of Alzheimer’s cases in the U.S. and worldwide developing in people of this age group. Given the percentage of each age group known to have Alzheimer’s disease, the at-risk population for Alzheimer’s is essentially everyone over the age of 60.
If an Alzheimer’s sufferer can be treated with approved drugs and kept out of a long-term care facility for as little as six months, not only he or she will enjoy a higher quality of life, but the savings for healthcare systems worldwide would be enormous.
Which populations have the highest risk of Alzheimer’s?
The high-risk population is everyone over the age of 75 and those over 65 who also have added risk factors such as high blood pressure, stroke or family history. Transitioning from age 65 to 75 increases the likelihood of Alzheimer’s disease from one in 10 to one in seven. If added risk factors are present, the probability becomes even greater.
This is especially evident in those over age 85. One study showed that nearly half of all people age 85 and older have some form of dementia, and this group is at the highest risk of Alzheimer’s disease. This age group is also one of the fastest-growing segments of the population. Four million Americans are currently age 85 or over; by 2050, the U.S. Census Bureau estimates this group will grow to nearly 19 million Americans.