Alzheimer’s Disease, Its Causes, Symptoms, And Therapy

First described by German neuropathologist Alois Alzheimer in the early 1900’s, Alzheimer’s disease is a complex, gradually progressive, degenerative neurological disorder characterized by devastating impairments in memory, thinking and reasoning and subsequently, associated behavioral changes. While estimates between studies vary, researchers approximate that around 47 million people suffer from dementia caused by Alzheimer’s, with the prevalence predicted to triple to more than 131 million by 2050 as a greater majority of the population makes their way into the older years. The disorder is irreversible and terminal, and through the course of its development, destroys an individual’s ability to learn, make judgments, communicate and eventually, dependently accomplish activities of daily living. However, accumulating evidence now shows that exercising four to five times a week may delay the progression of Alzheimer’s, especially in individuals with toxic accumulations of beta amyloid – the neuron-clogging protein that appears to be the causal factor and marker for memory regression.

The definitive causal effects of Alzheimer’s remain largely unknown. Growing evidence suggests, however, that there are several genetic and environmental risks factors which may include, but are not limited to: diabetes, hypertension, obesity, depression, smoking, low educational attainment and physical inactivity. It is believed that in early-onset Alzheimer’s a genetic mutation may be to blame while in late-onset Alzheimer’s, a complex series of progressive changes may result in the disease. Interestingly enough, approximately 40-80% of individuals diagnosed with Down syndrome are diagnosed with early-onset Alzheimer’s disease as a result of the fact that the extra chromosome they possess contains the gene that generates amyloid protein.

What has been identified in postmortem Alzheimer’s patients is the presence of extracellular plaques containing beta amyloid protein and neurofibrillary tangles containing tau protein in the frontal and temporal lobes of the brain – most specifically, the hippocampus. These abnormalities disrupt the flow of neuron impulses and result in Alzheimer’s symptomology. In addition, some autopsies have shown a significantly lower number of nerve cells and connections that are vital to both memory and mental abilities as the disease spreads and cells lose their ability to do their job and are subsequently no longer able to survive. Though some studies have shown that most individuals will develop plaques and tangles as they age, patients with Alzheimer’s have been found to develop them in greater numbers and beginning in the areas crucial to memory. Those with family members who have been diagnosed are also at an uncontrollably increased risk of developing the disease, as are individuals who have suffered from a serious head injury.

Though symptoms may vary widely, most of those who are diagnosed notice an initial “forgetfulness” that is severe enough to affect their ability to function (i. e. misplacing items, becoming confused or lost in familiar places, having trouble with language, etc. ). Toxic changes of the brain related to Alzheimer’s disease begin prior to signs of the disease and the many stages of the disease often overlap, also making it difficult to identify in which specific stage a person may be. While there is no certain evidence to say that Alzheimer’s disease is caused by the aging process, as a result of the fact that there is a notably higher number of individuals with Alzheimer’s disease in their older age, most will explain away these unusual behaviors as a normal part of the aging process – especially if they appear to be entirely healthy physically. However, in doing so, this results in a lack of effective intervention. Research continues to observe how brain atrophy, mitochondrial dysfunction, inflammation, vascular damage and the presence of free radicals contribute to Alzheimer’s damage.

Pharmacotherapy has always been in a dominant position for the treatment of Alzheimer’s. Some drugs such as cholinesterase inhibitors are used to block the enzyme responsible for destroying acetylcholine – a neurotransmitter. NMDA antagonists are used to block neurotransmitters from activating receptors that result in degeneration of the cells. These two classes of drugs are not affected by exercise. Other medications may also be used for the management of non-cognitive symptoms. However, these drugs are often helped to lessen and stabilize the symptoms of Alzheimer’s, they have shown to further cognitive decline in memory and executive function in some older adults. Neurosurgical approaches have also failed to prove effective to date in the treatment of Alzheimer’s. Consequently, accumulating and promising evidence has shown that exercise may amend or reduce the progression of cognitive impairment and is thus, much more effective in Alzheimer’s management.

Some studies have found that regular exercise maintains the integrity of the brain’s white matter which encompasses billions of nerve fibers and is linked to executive function. Of the lifestyle changes that have been studied, regular physical exercise has been identified to improve thinking and memory, reduce the likelihood of dementia and even, have a protective and healing effect on brain functioning. Physical exercise increases blood circulation to the brain which subsequently triggers a number of neurobiological mechanisms, increases protective chemicals, and counters some of the natural age-related reductions in cognitive function. In doing so, physical exercise improves function and endurance of cells and their respective pathways and thus, functional capabilities of the individual, reduces neurological symptoms and enhances neuroplasticity as well as decreasing rates of hippocampal (i. e. part of the brain that deals primarily with learning and memory) atrophy. Jogging, walking, biking, swimming and stretching may also prevent the progression of Alzheimer’s as well as metabolic diseases, which are all risk factors for diseases affecting the brain. However, although physical exercise has been identified as a powerful instrument for slowing the decline of physical and cognitive decline, there is currently no consensus regarding the best regimen.

The most basic recommendations of exercise in Alzheimer’s patients are fifteen minutes or more daily of walking which can improve cognition, and moderate-to-high-intensity resistance training which can not only improve motor function in progressed Alzheimer’s disease, but also help to reduce the risk of developing Alzheimer’s by upwards of 50%. Socialized exercise has also been proven to be an important aspect for this population as there may be a lack of interest in many Alzheimer’s patients. Incorporating a number of balance and coordination exercises into both aerobic and anaerobic practices also play a part in improving postural and motor functioning, reducing the risk of falls in Alzheimer’s patients. In an interesting series of events, however, one study found that women had more pronounced increases in cognitive performance and executive functioning than men following six months of aerobic exercise. Nonetheless, it is important for those prescribing exercise to individuals with Alzheimer’s disease doing so in confidence that the individual will have someone else with them as they perform exercise. This is due to the fact that these individuals may have difficulty with endurance and coordination. Defining the most optimally-effective preventative exercise prescription proves to be challenging as a result of the questionable evidence found, but the range of opportunity for beneficial effects of physical exercise is broad, and something that even leisurely physical activity can fall into.

Alzheimer’s disease is one of the principal causes of decreased quality of life amongst aging individuals, though exercise is proving to be one of the greatest improvements in the management of the disease. Scientists are constantly working to advance our understanding of Alzheimer’s, and the intense, ongoing research regarding exercise’s effect on Alzheimer’s patients offers hope to those who once saw Alzheimer’s as a diagnosis that would leave them without a medical means to better their quality of life. Although the quality of evidence may be minimal and it is challenging to draw specific and practical exercise recommendations, multicomponent exercise interventions are a promising, cost-effective way in which to prevent the onset of Alzheimer’s disease, as well as to manage the slow decline in functional capacity of Alzheimer’s patients.