Alzheimer's disease is a progressive neurodegenerative disorder that primarily affects the brain resulting in a slow decline in memory, cognitive function, and the ability to perform simple daily tasks. Alzheimer's disease is the most prominent cause of dementia, a general term for deteriorating intellectual ability interfering with activities that allow normal living. The disease begins with mild memory loss and confusion but continues to worsen, eventually leading to an inability to talk or even recognize relatives. Increased death of neurons in the brain characterizes Alzheimer's disease, with particular effects on the parts responsible for memory, thought, and language. What causes this neuronal death is not fully understood, but it is attributed to genetic factors, environmental factors, and lifestyle that trigger abnormal changes in the brain. Most notable are neurons that accumulate amyloid plaques and tau tangles that impair cell function and eventually lead to cell death. Amyloid plaques are abnormal clumps of a protein called amyloid-beta, which accumulate outside neurons during their lifetime. These plaques are believed to interfere with communication carried out by brain cells; their presence is considered one of the hallmarks of Alzheimer's disease. Tau tangles are twisted strands of another protein, tau, which normally helps stabilize the internal structure of neurons. In the case of Alzheimer's disease, tau becomes abnormal, causing the internal support structure of neurons to collapse, leading to cell death. These plaques and tangles together are believed to disrupt the normal functioning of the brain, leading to the cognitive decline seen in Alzheimer's patients. Currently, it is understood that the causes of Alzheimer's disease are still not well established, unlike the various risk factors that increase the likelihood of developing the disease-aging. It is well known that age is the most important risk factor as the likelihood of showing symptoms of Alzheimer's disease increases with age. Most patients with Alzheimer's disease are aged 65 years or older. However, it can also occur in patients younger than this age; early-onset Alzheimer's is one example, where the individual develops the disease before the age of 65. Nevertheless, the genetic factor plays an important role in the etiology of this disorder. Family history, especially if a close relative, such as a parent or sibling suffers from the disease, increases the risk for the individual. Gene mutations such as APOE have a recognized influence on the likelihood of developing Alzheimer's. One of the variants of APOE, AMPOE-E4, predisposes the individual to such disease, while other variants may provide relative protection. They will certainly not develop the disease, which is mostly due to the many genetic variations that favor one to acquire Alzheimer's disease without any contraindications. Other risk factors include certain lifestyle and environmental factors. These, in fact, increase the risk of developing Alzheimer's disease in people with high blood pressure, diabetes, high cholesterol, or previous experience of head injury. People with sedentary lifestyles, poor diets, or adults who experience chronic levels of stress may also be more susceptible. Growing evidence supports the claim that a lack of cognitive stimulation, social engagement, and lifelong learning may lead to the development of Alzheimer's, while staying mentally and socially active may offer some protection against cognitive decline. Alzheimer's disease is associated with a fatal progressive decline in cognitive function. Early symptoms include mild amnesia and confusion and some language impairment. In the later stages of the disease, individuals may have severe memory loss, especially with regard to recent events, and may not recognize familiar faces and places. There is often a change in mood and behavior, as well as increased irritability, anxiety, and depression. Further stages may see a decrease in everyday activities such as cooking, dressing, laundry, and personal hygiene. In the later stages of this disease, patients are usually completely dependent on caregivers to meet their daily needs. Patients may lose the ability to speak or communicate verbally, and motor skills may be impaired, leading to difficulty in walking and coordination. The final stage of this condition is characterized by varying levels of deterioration in the patient's condition, difficulty in swallowing, incontinence, and eventually succumbing to secondary complications such as pneumonia or other infectious causes, which often lead to death. Diagnosing Alzheimer's disease is a complex process and usually involves medical history evaluation, cognitive testing, and imaging studies. Indeed, because there is no single test to definitively diagnose Alzheimer's, doctors have to assess cognitive abilities and physical health as well as the patient's symptoms to conclude a diagnosis. The neuroimaging technique traditionally used in diagnosing Alzheimer's is MRI or PET to detect structural and functional changes in the brain, for example, loss of shrinkage in selected areas of the brain. Nevertheless, a definitive diagnosis can be made by detecting amyloid plaques and tangles of tau protein in the brain during autopsy. There is no cure for Alzheimer's disease at this time. The only method of treatment is symptomatic control and prevention of disease progression. Currently, there are a few approved drugs for the treatment of Alzheimer's, cholinesterase inhibitors and glutamate regulators. Cholinesterase inhibitors work by increasing the levels of acetylcholine, a neurotransmitter that is often deficient in Alzheimer's patients; for example, these drugs include donepezil, rivastigmine, and galantamine. These drugs improve memory and cognition; however, the above changes are minor and transient. Protecting brain cells from injury is a function performed by this type of glutamatergic modulator. Memantine is an example of one of such drugs.
As a complement to medications, many non-pharmacological aspects such as cognitive therapy, occupational therapy and behavioral methods can enable relatives or people suffering from Alzheimer's to cope with the disease. However, most of these methods are geared towards preserving or improving cognitive ability and enabling the individual's independence while assisting patients and caregivers. It also provides people with the experience of modern life, including the appropriate environment, social and emotional support so that their general well-being can be improved using Alzheimer's aid.
Researchers are still investigating Alzheimer's disease and conducting developmental studies regarding its possible future treatments or cures. They also want to find better knowledge about the basics of the disease, including amyloid plaques and the tau tangles that make it up, in order to develop treatments that will work against these proteins. Immunotherapy is an area of active research evidenced by early successes in clinical trials and aims to stimulate the immune system to clear amyloid plaques. Likewise, breakthroughs in genetic research may enable better forms of treatment, even the possibility of early diagnosis and customized therapies.
Meanwhile, researchers are also working on methods of prevention. Although there is no guarantee that someone will avoid Alzheimer's altogether, some evidence suggests that a healthy lifestyle may avoid or delay the disease. Regular physical activity, a healthy diet rich in fruits and vegetables and low in lean fats, good weight management and good care of chronic health problems such as diabetes and high blood pressure are among these measures. Mental activity, social attachment and emotional well-being are other contributors to cognitive health.
The impact of this disease goes far beyond the actual person suffering from it. There is an emotional, physical and financial impact on those who care for a person with Alzheimer's – often family members – as they feel the burden of care and all that is involved in providing support to an ill loved one. With the ageing of the global population, the number of people suffering from Alzheimer's disease will increase dramatically, resulting in a huge burden on the healthcare system and society at large. Therefore, for effective treatment, diagnosis at an early stage and supportive care are in greater demand than ever before.
Alzheimer's disease is a fatal neurodegenerative disorder that is affecting millions of people worldwide and causing tremendous cognitive decline in addition to impairing the ability to live an independent life. Although it is under constant investigation, no scientifically proven known cause of Alzheimer's exists yet. Environmental, genetic and lifestyle factors appear to play a role in its presentation, and no exact trigger has been identified so far. There is no cure available for this disease and only symptom control and slowing methods can be applied in this situation. Hence, with the increasing spread, research on better clarity on the disease, better treatment modalities and possible cures has to continue.
