Alzheimer's disease is a progressive form of dementia. It is a neurological disorder that causes the brain to shrink and brain cells to die. It affects the person's thinking, behavioral, and social skills, which means it affects his ability to function independently. This disease was named after Dr. Alois Alzheimer in 1906. He found two abnormal structures in a woman's brain after she died of an unusual mental illness. These two structures were plaques and tangles, which are the main features of Alzheimer's disease:

Plaques - The beta-amyloid proteins clump together to form plaque that build-up between nerve cells, or neurons.

Tangles - These are twisted fibers of another protein called tau that develops inside cells or neurons.

Another feature is the loss of connections between nerve cells. Many other complex changes in the brain are thought to play a role in Alzheimer's too. These damages in the brain cause Alzheimer's disease. This damage first takes place in parts of the brain that are associated with memory, such as the hippocampus and the entorhinal cortex. It gradually starts affecting the cerebral cortex, which is responsible for language, reasoning, and social behavior Many other areas of the brain are eventually affected. 

Symptoms:

Symptoms of Alzheimer's disease vary according to the stage of the condition. Generally, it starts affecting daily functions of a person such as:

• Memory loss
• Language
• Behaviour and personality
• Reasoning

Symptoms of severe stage of Alzheimer's:

• Almost total memory loss
• Loses their communication ability, they can hardly speak few words or phrases.
• Becomes unaware of surroundings, which leads to confusion
• Easily catches infections, especially pneumonia and skin infections.

Risk factors of Alzheimer's disease:

• Age (above 60-65)
• Hereditary
• Traumatic head injury
• Depression
• High blood pressure
• Cardiovascular disease

Prevention:

The study shows living a healthy lifestyle helps protect your brain from cognitive decline. Here are some strategies that you can use to prevent or reduce the risk of developing Alzheimer's disease.

Maintain physical fitness - Exercise increases the blood flow and oxygen to your brain, which maintains brain cell health.

Stay mentally fit - Read, do crossword puzzles, play board games or chess, or play any musical instrument which requires brain work.

Be socially active - Regularly talk with family and friends; join group activities such as religious groups, exercise classes, book clubs or laughter clubs as they say laughter is a best medicine.

Eat healthy - Follow an age-appropriate, well-balanced diet. 

People with Alzheimer's never really notice their mental health decline, so people around them like family and friends should pay attention seek medical help if they observe any of the above symptoms. Be aware; take care of loved ones because Alzheimer's can be difficult for both patient and family.