In the first interview with the media since the death of comedian Robin Williams, his wife Susan Williams said that the Oscar winner was "just disintegrating" physically and mentally in the months before his death.
Williams, who died in August 2014 at age 63, had hanged himself with a belt at their California home.
He was diagnosed with Parkinson's disease three months prior to his suicide, and an autopsy found he also had Lewy body dementia (LBD), which causes a progressive decline in mental abilities, his widow said.
While LBD is not a rare disease - it affects nearly 1.4 million individuals in the United States - it is known to be underdiagnosed because its symptoms can closely resemble other more commonly known diseases like Alzheimer's and Parkinson's.
Here are some things you need to know about LBD:
1. HOW IT GOT ITS NAME
The disease is named after German neurologist Friederich Lewy. In 1912, while he was researching Parkinson's disease, Lewy discovered abnormal protein deposits that disrupt the brain's normal functioning in people with Parkinson's.
2. WHO CAN GET THE DISEASE
LBD can affect both men and women. The disease becomes more common over the age of 65, but people under 65 can develop it in certain cases.
3. WHAT ARE THE SYMPTOMS
People suffering from LBD will experience symptoms such as delusions, changes in thinking and reasoning, trouble interpreting visual information, acting out dreams and visual hallucinations.
It also shares symptoms with other forms of dementia, such as a hunched posture, balance problems and rigid muscles like Parkinson's and memory loss that may be significant but less prominent than in Alzheimer's.
4. HOW COMMON IS IT
LBD accounts for around 4 per cent of all recorded dementia. However, based on studies of brain tissue after death, scientists think it may represent as much as 10 per cent of all dementia.
5. IS THERE A CURE
There is currently no cure or any medications aimed at specifically treating the disease. Doctors may prescribe the same drugs used to treat Alzheimer's and Parkinson's for the treatment of LBD. However, some medications can worsen LBD symptoms.