Alzheimer’s disease is a progressive, degenerative brain disease and the most common form of dementia, a group of brain disorders that affect a person’s memory, thinking and ability to interact socially. Alzheimer’s disease affects about 1 in 15 people over 65 years, and almost 1 in 4 people over 85 years.
At present, we don’t know what causes Alzheimer’s disease. We do know that people with this illness have abnormal material that builds up in their brain. These protein ‘tangles’ and ‘plaques’ disrupt communication between brain cells and lead to eventual cell death and brain shrinkage. There is currently no cure for Alzheimer’s disease.
While each person experiences a slightly different set of symptoms, the first noticeable symptoms of Alzheimer’s disease in most people is typically memory loss and difficulty in finding words in both speech and writing. Because such lapses are common and a normal part of ageing, the onset of the illness may not be recognised immediately.
As the disease progresses, people around the affected person may begin to notice signs of the disease. The person with Alzheimer’s disease may begin to find it difficult to plan and organise, for example keeping track of monthly finances, and have less knowledge or memory of recent events. They may become withdrawn.
Later in the disease larger deficits in thinking and thought processes may appear, for example difficulties with basic mental arithmetic or inability to remember important personal details, such as their address. The affected person may become confused about where they are or what day it is.
In the severe stages of the disease, the affected person’s personality and behaviour may change. They may experience delusions and hallucinations, have disrupted sleep patterns and need help with dressing and toileting.
We don’t know what causes Alzheimer’s disease. Risk factors include age, having a first degree relative with the disease, having had a head injury in the past, and having low levels of physical activity, hypertension, diabetes, high cholesterol or atrial fibrillation.
There are two types of Alzheimer’s disease: early-onset and late-onset. Early-onset Alzheimer’s disease is rare, affecting only about 5% of people with the disease. People with the early-onset form usually develop the disease between the ages of 30 and 60. Late-onset Alzheimer’s disease makes up the bulk of cases and affects people after the age of 60.