According to research, Alzheimer’s disease can affect individuals’ quality of life in profound ways. It is a common disease in the population, especially the elderly's. It is estimated that individuals over 65 years of age approximately 6% of people have Alzheimer’s disease and individuals over 85 years of age, the prevalence increases to 50%.
Alzheimer’s disease is one of the most common forms of dementia which worsens as it progresses and eventually leads to death. Alzheimer’s disease is a serious disorder of the brain which significantly affects the ability of a person to do their daily activities.
In medical terms, Alzheimer's disease is associated with the injury or death of neurons in the hippocampus brain region which is responsible for memory and learning. As this disease progresses, it affects the entire brain region. Amyloid beta is a protein in the brain which is associated with neural development. Evidence indicates that changes in the CFS levels of amyloid beta are associated with the development of Alzheimer's disease. Alzheimer’s disease is of two types:
1. Early onset Alzheimer’s disease
Early onset Alzheimer’s disease is also known as familial Alzheimer's disease and most of the cases of this type occur due to carrying mutations in one of the three - presenilin 1, presenilin 2, and amyloid precursor protein genes. Evidence suggests that more than 230 mutations has been found in one of the three genes that is involved in this type of Alzheimer's disease. These mutations lead to the production of 42 amino acids form of amyloid, resulting in the development of early onset Alzheimer's disease.
2. Late onset Alzheimer’s disease
Late onset Alzheimer's disease is also known as sporadic Alzheimer's disease and it is strongly associated with factors like oxidative stress, mitochondrial damage, and ApoE polymorphism in the vascular endothelium. Late onset Alzheimer's disease is linked to various risk factors such as diabetes, hypertension, obesity, and other metabolic syndromes.
How Alzheimer’s disease affects the brain?
The human brain consists of billions of cells and each cell is interconnected to many other cells in order to function normally. These nerve cells perform their jobs in groups and each group is responsible for some special tasks such as memory, thinking, vision, and smell. These cells store information and communicate with other cells to function smoothly. Research suggests that Alzheimer’s disease occur when damage is caused to these cells.
Most often Alzheimer’s disease occurs due to the build up of plaque in the spaces between the nerve cells. A large number of plaques and tangles build up in the brain of patients having Alzheimer's disease. These plaques are the deposits of a protein, known as beta-amyloid.
What are the symptoms of Alzheimer’s disease?
Alzheimer’s disease is associated with a large number of symptoms but generally, it begins with symptoms like problems with memory, thinking, and behavior. As this disease progresses, it is also associated with other symptoms such as:
- Problems with language
- Problems with decision making
- Problems with vision (seeing objects in three dimensions)
Alzheimer’s disease can be categorized into three stages - mild, moderate, and severe.
- A mild form of Alzheimer's disease is accompanied by greater memory loss and other problems that are associated with the cognitive system such as getting lost, behavioral changes, and problems with keeping things safe.
- A moderate form of Alzheimer's disease basically occurs when the parts of the brain that controls language and consciousness are damaged. At this stage, memory loss gets worse and patients start to find problems in recognizing people. Along with problems with memory, patients also experience symptoms like hallucination and delusions.
- A severe form of Alzheimer's disease is basically a final stage which occurs when the plaques and tangles have spread in the entire brain. In this stage, patients are completely dependent on others.
What is Atypical Alzheimer's Disease?
Atypical Alzheimer's disease is another type of Alzheimer's disease. Generally, this disease begins with symptoms like memory loss and decline in the cognitive system. But many times the earliest symptoms of this disease are not memory loss and such cases are known as atypical Alzheimer's disease. The atypical Alzheimer's disease is also caused due to the build up of plaque and tangles, but in this case the first part to be affected is not hippocampus. Hippocampus is the part of the brain that controls memory. Atypical Alzheimer's disease is categorized into three:
Posterior cortical atrophy - It occurs when the areas at the back and upper rear of the brain, which are responsible for vision and awareness are damaged. As a result, the early symptoms include problems with reading and identifying things.
Logopenic aphasia - It occurs when the damage is caused to the left side of the brain which is responsible for speech. As a result, the early symptoms include the problems associated with speech.
Frontal variant - It occurs when the damage is caused to the lobes of the front brain that is responsible for reasoning. As a result, the early symptoms are associated with problems with decision making.
What are the risk factors for Alzheimer’s disease?
There are various factors that could lead to the development of Alzheimer's disease such as:
1. Age - It is one of the most common risk factors as the age of an individual increases, the risk of developing Alzheimer's disease increases. Most of the patients who develop this disease are more than 65 years old.
2. Genetics - It is a rare risk factor but many times some genes leads to the occurrence of this disease. Most often, Alzheimer's disease due to genetics occur before the age of 65
3. Medical conditions - Evidence suggests that there are various medical conditions that increase the risk of developing this disease. Sometimes, it develops as a complication of another medical condition such as diabetes, hypertension, smoking addiction, obesity, and other metabolic disorders.
Multiple studies have been conducted to investigate the role of health and lifestyle in the development of this disease and it was observed that people who adopt healthy lifestyle during their mid life are less likely to develop Alzheimer’s.