Alzheimer
Alzheimer's is the most common cause of dementia, a general term for memory loss and other cognitive abilities serious enough to interfere with daily life. Alzheimer's disease accounts for 60-80% of dementia cases.
Dementia is the name for a group of symptoms associated with an ongoing decline of brain functioning. It can affect memory, thinking skills and other mental abilities.
The exact cause of Alzheimer's disease is not yet fully understood, although a number of things are thought to increase your risk of developing the condition.
These include:
· increasing age
· a family history of the condition
· untreated depression, although depression can also be one of the symptoms of Alzheimer's disease
· lifestyle factors and conditions associated with cardiovascular disease
Alzheimer's is not a normal part of aging. The greatest known risk factor is increasing age, and the majority of people with Alzheimer's are 65 and older. Alzheimer’s disease is considered to be younger-onset Alzheimer’s if it affects a person under 65. Younger-onset can also be referred to as early-onset Alzheimer’s. People with younger-onset Alzheimer’s can be in the early, middle or late stage of the disease.
Alzheimer's worsens over time. Alzheimer's is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer's, individuals lose the ability to carry on a conversation and respond to their environment. On average, a person with Alzheimer's lives 4 to 8 years after diagnosis but can live as long as 20 years, depending on other factors.
Signs and symptoms of Alzheimer's disease
Alzheimer's disease is a progressive condition, which means the symptoms develop gradually over many years and eventually become more severe. It affects multiple brain functions.
The first sign of Alzheimer's disease is usually minor memory problems.
For example, this could be forgetting about recent conversations or events, and forgetting the names of places and objects.
As the condition develops, memory problems become more severe and further symptoms can develop, such as:
· confusion, disorientation and getting lost in familiar places
· difficulty planning or making decisions
· problems with speech and language
· problems moving around without assistance or performing self-care tasks
· personality changes, such as becoming aggressive, demanding and suspicious of others
· hallucinations (seeing or hearing things that are not there) and delusions (believing things that are untrue)
· low mood or anxiety
Microscopic changes in the brain begin long before the first signs of memory loss.
The brain has 100 billion nerve cells (neurons). Each nerve cell connects with many others to form communication networks. Groups of nerve cells have special jobs. Some are involved in thinking, learning and remembering. Others help us see, hear and smell.
To do their work, brain cells operate like tiny factories. They receive supplies, generate energy, construct equipment and get rid of waste. Cells also process and store information and communicate with other cells. Keeping everything running requires coordination as well as large amounts of fuel and oxygen.
Scientists believe Alzheimer's disease prevents parts of a cell's factory from running well. They are not sure where the trouble starts. But just like a real factory, backups and breakdowns in one system cause problems in other areas. As damage spreads, cells lose their ability to do their jobs and, eventually die, causing irreversible changes in the brain.
Two abnormal structures called plaques and tangles are prime suspects in damaging and killing nerve cells.
1. Plaques are deposits of a protein fragment called beta-amyloid (BAY-tuh AM-uh-loyd) that build up in the spaces between nerve cells.
2. Tangles are twisted fibers of another protein called tau (rhymes with “wow”) that build up inside cells.
Though autopsy studies show that most people develop some plaques and tangles as they age, those with Alzheimer’s tend to develop far more and in a predictable pattern, beginning in the areas important for memory before spreading to other regions.
Scientists do not know exactly what role plaques and tangles play in Alzheimer's disease. Most experts believe they somehow play a critical role in blocking communication among nerve cells and disrupting processes that cells need to survive.
It's the destruction and death of nerve cells that causes memory failure, personality changes, problems carrying out daily activities and other symptoms of Alzheimer's disease.
Alzheimer’s disease is caused by the abnormal build-up of proteins in the brain. The build-up of these proteins — called amyloid protein and tau protein — leads to cell death.
The human brain contains over 100 billion nerve cells as well as other cells. The nerve cells work together to fulfill all the communications needed to perform such functions as thinking, learning, remembering, and planning. Scientists believe that amyloid protein builds up in the brain cells, forming larger masses called plaques. Twisted fibers of another protein called tau form into tangles. These plaques and tangles block the communication between nerve cells, which prevents them from carrying out their processes. The slow and ongoing death of the nerve cells, starting in one area of the brain (usually in the area of the brain that controls memory) then spreading to other areas, results in the symptoms seen in patients with Alzheimer’s disease.