What is Dementia?

Dementia(formerly known as Alzheimer’s disease) is a collective term for patients with neurological changes that lead to abnormal decline in brain functions; it is also a disease that occurs due to the loss of brain functions, which would gradually affect memory, thinking, language use, judgment, behaviour and character. Patients will experience gradual deterioration in memory and other cognitive functions (such as learning capacity, comprehension, language use, sense of orientation and judgment); some patients will also have symptoms of depression, hallucinations or personality changes.
 
In a healthy and normal brain, nerve cells make use of nerve conductors to communicate, wherein acetylcholine plays a key role in learning and memory. Acetylcholinesterase is an enzyme in the cerebral circulation that breaks down acetylcholine for the management and control of message transmission. The acetylcholine level in the brain of dementia patients is abnormally low, which causes the loss of connection between nerve cells and the inability to transmit information, thereby making them unable to perform their functions of memory, learning and communication. Generally speaking, patients can live for eight to ten years on average upon diagnosis of dementia. Although some patients show a faster rate of deterioration, others may manage to live for as long as 20 years even after detection of the disease.


Source：律敦治及鄧肇堅醫院 - 認知障礙症照顧者手冊