Actor Bruce Willis has frontotemporal dementia: 6 facts about the condition

Action star Bruce Willis is best known for ‘Die Hard’ and ‘Armageddon’.

The condition of veteran actor Bruce Willis, who retired last year after a speech disorder diagnosis, has worsened, his family announced on February 16. "We now have a more specific diagnosis: frontotemporal dementia," they said.

Willis, 67, is best known for his roles in the films Die Hard, Armageddon and The Sixth Sense. He also appeared in the hit TV shows Moonlighting and Friends, for which he won two Emmy Awards (best leading actor in a drama series and outstanding guest actor in a comedy series).

Here are six facts to know about his diagnosis --  frontotemporal dementia:

- Frontotemporal dementia (FTD) affects the brain's frontal and temporal lobes. It is an uncommon type of dementia that tends of have an early onset. Most FTD cases are found among those aged between 45 and 65, according to the UK's National Health Service.

Actor Bruce Willis' 'condition has progressed' to dementia, says family

- The disorder has physical symptoms like movements becoming stiff or slower, muscle weakness and loss of bowel or bladder control. It also impairs speech and mental abilities. Patients may also act impulsively, feel a loss of motivation and neglect personal care. At later stages, frontotemporal dementia causes memory troubles.

- The cause of FTD is abnormal protein formation inside brain cells. This abnormality often has a hereditary link.

- FTD has two key variants -- frontal variant that impacts personality and behaviour and primary progressive aphasia that causes difficulties with speech and communication.

- FTD is not a life-threatening disease but can increase the risk of other, more serious illnesses. One of the most common causes of death in FTD patients is pneumonia. Another concern is fall-related injuries.

- There are no treatments for the condition at present but medicines may be prescribed to relieve its symptoms. These include antipsychotic medicines, antidepressants and sleeping aids.