Alzheimer’s disease is an irreversible, progressive brain disorder that slowly destroys thinking skills and memory. Alzheimer's eventually destroys the ability to carry out simple tasks. Most people with Alzheimer’s notice the first symptoms in their mid-60s.
Some people notice the symptoms earlier. This is called having early onset Alzheimer's.
What causes Alzheimer's?
The causes of Alzheimer’s disease are not understood. In some cases of early onset Alzheimer’s there is a genetic component. Whereas late onset Alzheimer’s comes from brain changes that happens over decades.
A combination of genetic, environmental, and lifestyle factors liekly cause Alzheimers. The importance of any one factor differs from person to person.
What are the signs of Alzheimer's?
The first Alzheimer's symptoms are often a decline in finding words, vision/spatial issues and/or impaired reasoning or judgment.
People first experience Mild Cognitive Impairment, before reaching a Dementia stage of Alzheimer's. The dementia stages of Alzheimer's are described below.
The first symptoms of Alzheimer's tend to be short term memory loss. People have a hard time remembering recently learned facts and are unable to learn new information.
Problems with attentiveness, planning, flexibility, and abstract thinking or impairments in semantic memory can also be a sign of the early stages of Alzheimer's.
Other symptoms such as, apathy, irritability and reduced awareness of memory difficulties are common. Mild cognitive impairment can be a transitional stage between normal ageing and dementia.
Most Alzheimer's sufferers are diagnosed at the Mild Alzheimer's stage. At the Mild Alzheimer's stage, sufferers experience greater memory loss and more cognitive difficulties. Problems include wandering, getting lost, trouble handling money, repeating questions, taking longer to complete tasks and personality and behavior changes.
In the Moderrate Alzheimer's stage, damage occurs in areas of the brain that control language, reasoning, sensory processing, and conscious thought. Sufferers experience more memory loss and confusion grow worse. People start having problems recognizing family and friends. Learning new things, carrying out multistep tasks such as getting dressed, or coping with new situations becomes difficult.
In the Moderate stage of Alzheimer's people may start having hallucinations, delusions, and paranoia. They may also behave impulsively.
In the Severe Alzheimer's stage plaques and tangles spread throughout the brain. The brain tissue shrinks significantly. Severe Alzheimer’s sufferers cannot communicate and are completely dependent. The Alzheimer's sufferer may now be in bed most or all of the time as the body shuts down.
The Brain and Alzheimer's
In Alzheimer's disease amyloid plaques accumulate between nerve cells or neurons in the brain. Amyloid is a protein fragment that the body produces normally. In a healthy brain amyloid fragments break down and are eliminated. In Alzheimer's the fragments accumulate to form hard insoluble plaques.
Neurofibrillary tangles are formed into insoluble twisted fibers inside the brain. The tau protein forms part of a structure called a microtubule. In Alzheimer's disease the tau protein is abnormal and the microtubule structures collapse.
As Alzheimer's progresses, brain tissue shrinks. The ventricles chambers within the brain that contain cerebrospinal fluid are noticeably enlarged.
In the early stage of Alzheimer's short-term memory begins to decline when the cells in the hippocampus degenerate. People with Alzheimer's lose the ability to perform routine tasks. As Alzheimer's spreads through the cerebral cortex, judgment worsens, emotional outbursts may occur and language is impaired.
Advancement of the disease leads to the death of more nerve cells and subsequent changes in behavior, such as wandering and agitation. In the final stage, people may lose the ability to feed themselves, speak, recognize people and control bodily functions. Memory worsens and may become almost non-existent. Constant care is typically necessary.