On the 10th anniversary of the death of Hollywood legend and comedic genius Robin Williams, celebrities have paid tribute to the “extraordinary, intuitive and sensitive” man that he was.

More than 20 co-stars, collaborators, directors and friends, including Sally Field (Mrs Doubtfire) and Billy Crystal (Comic Relief, Fathers Day), remembered the good times, and spoke about how the world is a lonelier place without him in their lives.

“I miss being able to talk with him, laugh with him, grow older with him,” Crystal told Vanity Fair.

But 10 years on, what more do we know about the research, clinical trials and possible cures for the deadly Lewy body dementia (LBD), with which he was posthumously diagnosed after his suicide on August 11, 2014.

The US National Institute of Neurological Disorders and Stroke (NIH) said the cause of LBD was still unknown, but it was making progress on diagnosis, risk factors and treatments.

Sadly, “there is currently no cure for LBD”, which has two related forms – dementia with Lewy bodies and Parkinson’s disease dementia.

But there are medications, therapies and support for carers, if caught early.

Williams’ widow, Susan Schneider Williams, who became a leading spokesperson on LBD, described it as a “ghost disease”.

“A few months before he passed, he was given a Parkinson’s [disease] diagnosis,” Schneider Williams told CNN at a Life Itself conference in 2022.

“But that was just the tip of the iceberg.”

The misdiagnosis was in May 2014, after Williams had been experiencing severe memory, movement, personality, reasoning, sleep and mood changes.

He had multiple tests to identify LBD, a disease associated with abnormal deposits of a protein called alpha-synuclein in the brain, explains the NIH.

“None of the doctors knew that there was this ghost disease underlying all of this … when that was revealed, that was like essentially finding out the name of my husband’s killer.”

In May, the Lewy Body Dementia Association reported that scientists were researching whether small samples of tissues “such as skin or saliva glands” could help make more accurate diagnoses possible during life.

Susan Schneider Williams and Robin Williams in New York in 2012. Photo: AAP

Since Williams’ death at age 63, Schneider Williams has made it a priority to correct misassumptions about his death, and educate others about this still relatively little known brain disease.

She served on the board of the American Brain Foundation for six years and remains one of their ambassadors. She also helped establish the Lewy Body Dementia Fund, which received a $US3 million ($4.6 million) research grant.

She contributed to the documentaries, Robin’s Wish, and Spark: Robin Williams and His Battle with Lewy Body Dementia, and wrote a detailed paper in the Neurology journal in 2016 that the LBD plaguing him was “the terrorist in my husband’s brain”.

“He hated that he could not find the words he wanted in conversations. He would thrash at night and still had terrible insomnia,” she said.

“At times, he would find himself stuck in a frozen stance, unable to move, and frustrated when he came out of it. He was beginning to have trouble with visual and spatial abilities in the way of judging distance and depth. His loss of basic reasoning just added to his growing confusion.

“It felt like he was drowning in his symptoms, and I was drowning along with him … Robin was losing his mind and he was aware of it.

“By wintertime, problems with paranoia, delusions and looping, insomnia, memory, and high cortisol levels – just to name a few – were settling in hard.”

When filming Night At The Museum 3 “Robin was having trouble remembering even one line for his scenes, while just three years prior he had played in a full five-month season of the Broadway production, Bengal Tiger At The Baghdad Zoo, often doing two shows a day with hundreds of lines – and not one mistake,” she wrote.

“This loss of memory and inability to control his anxiety was devastating to him.”

She said doctors and researchers wanting to mitigate the kinds of experiences her husband endured “have a tall order … but progress is being made.”

Two great mates, Robin Williams and Billy Crystal, at the 76th Academy Awards in 2004. Photo: Getty

On the anniversary of Williams’ death, celebrities from Hilary Swank and Matt Damon to Robert De Niro and Terry Gilliam, shared anecdotes of time spent with Williams throughout his near-50 years in the theatre, on stage or on movie sets.

“Our times together with Comic Relief were simply jazz,” Crystal said.

“The speed of his comedy was breathtaking. I felt like a bull rider: Stay on for eight seconds and you win. Our times offstage were so important to us. We could talk about anything with no attempts at humour. Kids, parents, life’s ups and downs.

“Then we’d have late-night calls where we could go for an hour or two as different characters. [One time] I was watching Ronald Reagan’s funeral and the phone rang.

“Hi, Bill, it’s me, Ron. I just wanted you to know I’m in heaven and all is good.”

“Oh, Mr President, what’s heaven like?

“Well, it’s really hot here.

“Wait, sir, if I may: If it’s really hot, you might not be in heaven. You might be in the ‘other place’.

“Oh, that explains why I’m in a hot tub and Nixon’s b–s are resting on the bridge of my nose.”