The Aging Brain and Alzheimer ’s disease

Most of us sense that time is passing and realize that at some point death will be inevitable. Before we get to that ultimate end our body goes through various changes will ultimately lead up to that point. On average human life expectancy ranges from 70 to 80 years. As we began to age and start to approach the latter part of middle to late adulthood, our senescence, the process of getting old, begins to sink in and become relevant. Throughout the adult life, all physiological functions at some point begin to gradually decline. Not only do we age but so does the brain, the most vital, largest, and most complex organ in our body. When does aging of the brain begin? Probably as soon as the end of puberty. One recent study concluded that aspects of age-related cognitive decline begin in healthy educated adults when they are in their 20s and 30s (Lamberts, Beld, van der Lely 1997). The human brain is responsible for everything that we do, waking in the morning, remembering who and where we are as well as our emotions as related to love, happiness or sadness. Most of our cognitive abilities deteriorate including inductive reasoning, spatial orientation and verbal memory.

The loss of spatial orientation ability underlies a common problem for the elderly, wandering. The shrinkage of one particular brain region, the hippocampus, is most likely responsible for this loss of orientation and wandering. As our brain ages it ages could lead us to the route of death via two ways. With an aging body as well as an aging brain, there’s not much left of us. Our brain could take the normal route to death which is being in the right state of mind or we can take the long difficult route to death that takes us through stages of disease. The brain can be affected by many diseases or disorders such as Alzheimer’s, Cerebral Infarct, Meningitis, and the list goes on. Our ability to remember and to recall our past is what links us to our families, our friends, and our communities. As we age, subtle changes in memory occur. Simple forgetfulness (the “missing keys”) and delay or slowing in recalling names, dates, and events can be part of the normal process of aging. Most normal changes in memory and thinking are of little importance. Not every memory problem becomes dementia, and not every cause of dementia is Alzheimer’s disease. But when memory loss prevents us from performing daily tasks and our accustomed roles in life, it becomes a health concern that needs further evaluation by healthcare professionals.

Memory has various forms that might be affected differently by aging. As we age, we maintain remote memory, procedural memory (performing tasks), and semantic recall (general knowledge) ( Hof, Morrison 2004) However, our ability to learn something new and recall it declines. Other changes can also occur with normal aging: Language comprehension (understanding the rules of language) is preserved as we age, as are vocabulary and one’s understanding of syntax—the way in which words are put together. But some modest decline is seen in our ability to dredge up words and in verbal fluency—one’s ability to “get the words out.” While one’s vocabulary remains unchanged as one ages, the speed with which one processes information gradually slows. For instance, one’s ability to solve problems can decline. In normal aging, so-called executive functions (like planning or abstracting) remain normal for everyday tasks but are slowed when one multitasks or is faced with novel tasks. A slowing of the speed of cognitive processing and reaction time (“hitting the buzzer”) occurs with aging.

Kathleen Berger in her textbook “The Developing Person throughout the Lifespan” (2011) describes Alzheimer’s Disease is one disease that is most feared and the most frequent type of dementia. Alzheimer’s disease is a progressive disease that damages the neurons/ nerve cells of the brain involved in memory, learning, language, and reasoning. As Alzheimer’s progresses, communication among the neurons breaks down. In early stages, short-term memory begins to fail. Over time, functions such as long-term memory, language, and judgment decline. Alzheimer’s disease is the most common cause of dementia in older adults. Dementia is a loss of mental functions—such as thinking, memory, and reasoning—that is severe enough to interfere with a person’s daily functioning. In the case of Alzheimer’s disease neuronal degeneration is not only reflected by neuron and synapse loss in certain areas but also by neuropathiclogic profiles such as neurofibrillary tangles (Morrison Hof 1997) There are two basic types of Alzheimer’s disease: Early-onset Alzheimer’s disease tends to strike people under age 65 and is more likely to run in families.

Late-onset Alzheimer’s disease, the much more common type, generally afflicts people after age 65. The exact cause of Alzheimer’s is unknown, although researchers studying this puzzling disease are making progress. The human brain is made up of billions of neurons, or nerve cells. Each one connects to thousands of other nerve cells, all of which communicate via chemical messengers. At any one moment, millions of these signals are speeding through pathways in the brain, allowing it to process and analyze information and send out instructions to various parts of the body. Deep inside one portion of the brain, is a structure called the hippocampus, which is thought to be where short-term memories are converted into long-term memories. Atrophy, partial or complete wasting away, affects the hippocampus and is often seen in the brains of Alzheimer’s patients. Futhermore, in these patients , the hippocampus and other areas of the brain involved in thinking and decision making are filled with two types of abnormalities—beta-amyloid plaques and neurofibrillary tangles.

Plaques are deposits outside and around the neurons, made up of dense globs of a protein called beta-amyloid, mixed with other cellular material. Tangles are made up of microtubules, part of the transport system inside nerve cells. Scientists are not sure whether these abnormalities cause Alzheimer’s, but they are the focus of a lot of research because Alzheimer’s patients have many more of them than healthy older people do. There are many types as well as stages of Alzheimer’s. Many doctors and researchers categorize Alzheimer’s in two different ways: by the type of disease and by the stages people with Alzheimer’s progress through (Swaab, Dubelar, Hofman, Scherder, Someren , Verwer 2002). Early-onset Alzheimer’s: This is an uncommon form in which individuals are diagnosed with the disease before age 65. Fewer than 10 percent of all Alzheimer’s disease patients have this type. Because of their genetic abnormality, people with Down syndrome are particularly at risk for a form of early-onset Alzheimer’s disease.

Adults with Down syndrome often are in their mid- to late 40s or early 50s when symptoms first appear. Late-onset dementia: The most common form of Alzheimer’s disease, late-onset dementia usually strikes after age 65. It occurs in almost half of all people over the age of 85 and may or may not be hereditary. Late-onset dementia is also called sporadic Alzheimer’s disease. Familial Alzheimer’s disease (FAD): This form of Alzheimer’s disease is known to be entirely inherited. FAD is extremely rare, accounting for fewer than 1 percent of all cases of Alzheimer’s disease. It has a much earlier onset (often in the 40s) and follows clear patterns of inheritance. In addition to age of onset, there are other differences among the types of Alzheimer’s. Younger people who develop Alzheimer’s disease have more of the microscopic changes found in the brains of people with Alzheimer’s disease. These changes include the twisted nerve cell fibers, known as neurofibrillary tangles, and a sticky protein called beta-amyloid, which forms structures called plaques.

Plaques and tangles are associated with damage to healthy brain cells and result in brain shrinkage or atrophy. It may be, though, that younger brains simply need to be more damaged before a person starts to show symptoms, so this may not reflect a true difference in the nature of the disease. A condition called myoclonus—muscle twitching and spasm—is more commonly seen in early-onset than late-onset Alzheimer’s. Some research suggests that people with early-onset Alzheimer’s disease decline at a faster rate than do those with late-onset Alzheimer’s disease. (Fotenos, Mintun, Snyder, Morris, Buckner 2008). Younger people who are diagnosed with the disease tend to be more physically fit and active, and many still have family and career responsibilities. As a result, they tend to feel more powerless, frustrated, and depressed upon diagnosis. Alzheimer’s disease generally affects memory and the ability to think logically.

Other important skills that may be impaired include language, complex motor activities, perception, and organizational skills. In its most severe form, Alzheimer’s disease can interfere with a person’s ability to perform daily tasks, such as dressing, bathing, and eating. Alzheimer’s disease is the single most common cause of dementia. Dementia is a sustained decline in thinking, with memory loss and at least one other area of deficit in great enough degree to interfere with social or occupational activities. Most patients’ symptoms progress slowly over a number of years. Symptoms may not be noticed early on. Sometimes, it is only when family members look back that they realize when the changes started to occur. The symptoms of Alzheimer’s disease may resemble those of other medical conditions or problems, so it is important to talk to your doctor for an accurate diagnosis

Studies show that chemical and structural changes occur in the brains of people with Alzheimer’s disease. These changes interfere with a person’s ability to process, store, and retrieve information. It is not known why these changes occur. (Swab, Dubelar, Hofman, Scherder, Van Someran, Verwer 2002). Scientists have found two significant abnormalities in the brains of people with Alzheimer’s disease: twisted nerve cell fibers, known as neurofibrillary tangles, and a sticky protein called beta-amyloid, which forms structures called plaques. Plaques and tangles are associated with damage to healthy brain cells, causing the brain to atrophy and shrink. Another characteristic of Alzheimer’s disease is the reduced production of certain chemicals in the brain that are necessary for communication between nerve cells. These chemicals, called neurotransmitters, include acetylcholine, serotonin, and norepinephrine.

In the area of the brain responsible for memory, the hippocampus, there is a loss of nerve cells, and decreases occur in the levels of chemicals needed for carrying messages back and forth between the nerve cells (Crews 2007). An estimated 5.4 million Americans of all ages have Alzheimer’s disease in 2012 (Evans DA, Funkenstein HH, Albert MS,1989). This figure includes 5.2 million people age 65 and older and 200,000 individuals under age 65 who have younger-onset Alzheimer’s. One in eight people age 65 and older (13 percent) has Alzheimer’s disease. Nearly half of people age 85 and older (45 percent) have Alzheimer’s disease. Of those with Alzheimer’s disease, an estimated 4 percent are under age 65, 6 percent are 65 to 74, 44 percent are 75 to 84, and 46 percent are 85 or older. The risk of developing Alzheimer’s disease increases as you grow older. At 65 years, 1 percent of the population is affected; at age 85, 30 percent to 50 percent has the disease. While it has been suggested that everyone might develop dementia after living long enough, it should be emphasized that Alzheimer’s is a disease and not simply an exaggeration of normal aging.

If you have family members who have Alzheimer’s, you are more likely to develop the disease, although a clear, inherited pattern of Alzheimer’s disease exists for fewer than 1 percent of all cases. Alzheimer’s disease strikes early and fairly often in certain families, often enough to be singled out as a separate form of the disease and given a label: early-onset familial Alzheimer’s disease, or FAD. Alzheimer’s disease is more prevalent among women than among men. Some studies have shown an association between Alzheimer’s disease and a history of significant head injury. Salib E, Hillier V (1997). Some studies have shown that low education levels are related to an increased risk for Alzheimer’s disease, although why this might be the case is not clearly understood. People with Down syndrome often develop Alzheimer’s disease in their 40s and 50s. One of the most publicized and controversial theories concerns aluminum which became a suspect in Alzheimer’s disease when researchers found traces of this metal in the brains of patients with Alzheimer’s disease ( Exley, Birchall 1993). Many studies since then have either not been able to confirm this finding or have had questionable results.

Aluminum does turn up in higher amounts than normal in some autopsy studies of Alzheimer’s patients but not in all. Various studies have found that groups of people exposed to high levels of aluminum do not have an increased risk. On the whole, scientists can say only that it seems unlikely that exposure to aluminum plays a role in Alzheimer’s disease. It seems that there is not a single test for diagnosing Alzheimer’s disease. Doctors can only diagnose probable Alzheimer’s disease after a thorough medical, psychiatric, and neurological evaluation, to rule out all other possible causes of dementia. Alzheimer’s disease cannot be positively diagnosed until after death, when the brain can be closely examined for certain microscopic changes caused by the disease. However, through thorough testing and a “process of elimination,” doctors today can diagnose probable Alzheimer’s with almost 90 percent accuracy. At this time, there is no cure for Alzheimer’s disease, there is no way of slowing the progression of the disease, and there is no treatment available to reverse its effects. But medicines can help patients with Alzheimer’s disease.

Unfortunately, there is no way to prevent Alzheimer’s, simply because it’s origins and controllable risk factors for Alzheimer’s disease are not yet known. However it is suggested that a lifetime of learning and keeping the mind active can help protect against the disease. One of the most exciting new areas of research involves the risk factors that affect how likely it is that a person will develop Alzheimer’s disease. An examination of the possible risk factors for Alzheimer’s—such as aging, family history, past significant head injury, genetic factors, and low education—leads to theories about how these risks produce plaques, tangles, and cell loss, characteristics that are common in Alzheimer’s disease. Similarly, examination of possible anti-Alzheimer’s factors—including the use of anti-inflammatory medication, certain genetic factors, antioxidant therapies, and high education or occupational demand—generates other theories. Many potential therapies suggested by these theories are now being tested, will be tested in the near future, or are under development. Alzheimer’s disease (AD) gets worse over time, and the course of the disease varies from person to person.

Some people have the disease for only the last five years of their lives, while others may have it for as long as 20 years. The most common cause of death in people with Alzheimer’s disease is infection. In managing the disease, physical exercise and social activity are important, as are proper nutrition, health maintenance, and a calm and well-structured environment. Alzheimer’s disease, like many other chronic illnesses, will not only affect the patient but also the caregiver both physically and mentally. Taking action early will allow you to understand and deal with the many effects of a chronic illness. Learning to manage stress will help you to maintain a positive physical, emotional, and spiritual outlook on life. If depression is present, medications other than those treating the physical illness may be ordered to help lift your mood. Although no cure for Alzheimer’s disease is now available, planning and medical/social management can help ease the burden on both patients and family members.

Physical exercise, good nutrition, activities, and social interaction are important. A calm, structured environment also may help the person with Alzheimer’s disease to continue functioning as long as possible. Currently, about 4 million Americans suffer from Alzheimer’s disease, and about 22,000 people die from Alzheimer’s disease every year. The Alzheimer’s Association estimates that 1 in 10 people over age 65 and nearly half of people over 85 have Alzheimer’s disease. The number of Americans with Alzheimer’s disease is expected to increase to 14 million by 2050, unless a cure or preventive measure can be found. Alzheimer’s is a very serious disease that doesn’t discriminate. Men and women are both prone to this disease, according to (ALZ.org 2012), More women than men have Alzheimer’s disease andother dementias. Almost two-thirds of Americans with Alzheimer’s are women. Of the 5.2 million people over age 65 with Alzheimer’s in the United States 3.4 million are women and 1.8 million are men.

Based on estimates from ADAMS, 16 percent of women age 71 and older have Alzheimer’s disease or other dementias compared with 11 percent of men. I chose to write about Alzheimer’s because as I watch several of my relatives aged, I wonder if any or neither of them will be affected by this disease. I recently lost a church member to this disease and as I watched her deteriorate and ultimately lose her life to it, I wondered how could this have happen to such a beautiful and sharp woman. Well now that I have done extensive research on Alzheimer’s I have more information than I expected. I guess we sometimes take for granted how fragile life can really be, but not me at this point. I plan to educate my family members about this disease so that we all can become familiar with it and also ensure that our aging relatives have regular doctor visits.

References

Alzheimer’s Disease Organization (2012). 2012 Alzheimer’s Disease Facts and Figures. Retrieved December 1, 2012 from http://www.alz.org/downloads Berger, K. (2011). The Developing Person Through the Life Span. New York:
Worth Publishers. Crews DE. Senescence, Aging and Disease. Journal of Physiological Anthropology. 26(3): 365- 372, 2007 Journal: Progress in Brain Research – PROG BRAIN RES , vol. 138, pp. 343-373, 2002 Evans DA, Funkenstein HH, Albert MS, et al. Prevalence of Alzheimer’s disease in a community population of older persons: higher than previously reported. JAMA. 1989;262:2551-2556 Exley C and Birchhall, JD, Age and Aging, ISSN 0002-0729, 09/1993, Volume 22, Issue 5, pp. 391 – 392 GERIATRICS & GERONTOLOGY Fotenos, Anthony F., Mark A. Mintun, Abraham Z. Snyder, John C. Morris, and Randy L.

Buckner. 2008. Brain volume decline in aging. Archives of Neurology 65(1): 113-120

Hebert LE, Scherr PA, Bienias JL, Bennett DA, Evans DA. Alzheimer’s disease in the US
population: prevalence estimates using the 2000 census. Arch Neurol. 2003;60:1119-1122 Hof, P. R., J. H. Morrison. “The Aging brain (includes Alzheimer’s):Morphomolecular
senescence of cortical circuits.” Trends in Neurosci 27 (2004): 607-613. Morrison, John H.; Hof, Patrick R. “Life and Death of Neurons in the Aging Brain”. Publication: Science, Vol. 278, Iss. 5337, p. 412 (1997). Publication .. Salib E, Hillier V. Int J Geriatr Psychiatry. 1997 Mar;12(3):363-8. PMID: 915272