Alzheimer’s disease is the most common cause of dementia worldwide. Those over the age of 60 are most vulnerable to the illness, but it can occur in younger people too, especially when there is a family history of early-onset dementia.
The disease is progressive and 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.
“Alzheimer’s dementia (AD) differs from normal brain ageing,” says Dr Kim Laxton, a psychiatrist at Akeso Clinic.
“With age, the brain, like any organ and muscle in the body, becomes weaker and less effective in its functioning, particularly in its cognitive capacity. Alzheimer’s dementia is a pathological ageing of the brain. Loss of memory and cognitive abilities is the most common symptom and, with time, the person becomes wholly dependent on others for the basic activities of daily living.”
There is a genetic component that renders someone susceptible to the onset of the disease, she adds, but genetics is not the only factor involved in the development of older-age AD. “Certain genetic alleles, present in a person, might predispose them to AD, but other factors such as hypertension and high cholesterol are also implicated as risk factors.”
Early stages of AD presents with word-finding and short-term memory difficulties, such as losing keys, forgetting to pay bills, forgetting names of people and objects, and becoming lost in familiar places.
“Two abnormal structures called plaques and tangles are prime suspects in damaging and killing nerve cells in the brain,” says Laxton. “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.”
Facts and figures
- Alzheimer’s dementia (AD) is evident in both the developed and developing world and is the cause of up to 75% of all dementias globally.
- The most important risk factor for the development of Alzheimer’s Disease is age. With an ageing population that is growing substantially as a result advancing medicine and lifestyle enhancements, there is an expected increase in the number of AD patients.
- AD in those over the age of 65 years is expected to increase from 420 million in the year 2000 to nearly 1 billion by 2030, by the proportion of older people seeing an increase from 7% to 12%.
- The prevalence rate percentages show an increasing trend of the number of AD diagnoses made as age increases. The prevalence rate in the 65-69 year age group is about 1.4% and increases to 23.6% in those 85 years and older.
- According to South Africa’s 2011 census, there are approximately 2.2 million people in South Africa with this particular form of Dementia.