neurologist

British actor Patrick Stewart died Wednesday at 86. His spokesperson said Thursday that he died from Alzheimer’s disease and Lewy body dementia.

The two conditions often occur together, said UCLA neurology professor Dr. Keith Vossel, and when that happens, the individual’s decline may be faster.

Lewy body dementia is the second-most-common form of degenerative dementia, behind Alzheimer’s disease, Vossel said. It occurs when a protein called alpha-synuclein aggregates in clumps inside the brain. The condition is under-recognized and under-diagnosed in part because its symptoms can overlap with those of Alzheimer’s.

Other celebrities who suffered from the condition include Robin Williams, who took his own life at 63, and Casey Kasem.

The condition is named after Friedrich H. Lewy, the neurologist who discovered the brain abnormalities in the early 1900s, according to the Alzheimer’s Assn. website.

“Essentially the only way to really diagnose these conditions together is after an autopsy and to see the hallmark features of the diseases under the microscope,” Vossel said.

Lewy body dementia symptoms tend to start with rapid eye movement sleep behavior disorder, such as screaming or kicking during sleep. A sufferer may have rigidity or tremors in one of their arms or legs. And they may experience slowness of movement.

A patient may be diagnosed with Lewy body dementia after also experiencing cognitive symptoms within one year of motor symptoms. Cognitive symptoms could include illusions or hallucinations — some patients report sensing a shadowy figure nearby — and difficulties with problem solving and navigation. The condition is also marked by dramatic fluctuations in alertness that occur within hours of the same day.

Another early feature of Lewy body dementia is anxiety, Vossel said.

By contrast, Alzheimer’s disease typically is associated with memory and language loss, and is more associated with apathy and depression than with anxiety. The course of Alzheimer’s disease is slightly slower than that of Lewy body dementia, according to Vossel.

Lewy body dementia is more common in men than in women. Anyone over the age of 60 is at higher risk of having a degenerative condition. Lewy body dementia is most common in people in their 70s to 80s, he said.

There is currently no cure for Lewy body dementia, which is terminal and progressive. After a diagnosis, people can typically expect to live six to eight years before they need 24-hour care, Vossel said.

But medication can help manage symptoms. Clinical studies have found that cardiovascular fitness can slow the rate of decline, Vossel said.

Those who suspect they have Lewy body dementia symptoms should contact a neurologist or a clinician trained in either geriatric medicine or geriatric psychiatry for an evaluation, Vossel said.

It is unclear when Billy Joel will perform again.

The 77-year-old singer has to take “a series of tests” before being able to tour again, he told the Hollywood Reporter in a health update following his 2025 brain disorder diagnosis.

“I’m not allowed to drive,” Joel said in the interview published Thursday. “And I can’t do performances because what the neurologist told me, every time you do a show, it’s like you’re getting a concussion.”

Joel canceled concerts in May 2025 after revealing two months before that he had a brain disorder known as normal pressure hydrocephalus, or NPH, which causes physical and mental issues.

“This condition has been exacerbated by recent concert performances, leading to problems with hearing, vision and balance,” Joel said in a statement on his Instagram in May 2025. “Under his doctor’s instructions, Billy is undergoing specific physical therapy and has been advised to refrain from performing during this recovery period.”

NPH is a brain disorder in which excess cerebrospinal fluid accumulates in the brain’s ventricles, according to the Alzheimer’s Assn. It can cause cognitive issues, difficulty walking and the loss of bladder control. Those suffering with NPH often walk with a wide stance and their bodies bent forward as if they were trying to maintain balance on a boat — a feeling that Joel described while on Bill Maher’s podcast “Club Random” on July 21, 2025.

Other symptoms include mild dementia that involves short-term memory loss, a lack of interest in daily activities and difficulty completing routine tasks.

NPH is one of the few causes of dementia that can be controlled or reversed with surgical treatment, usually involving the placement of a shunt.

It is unclear whether Joel underwent the procedure, although the “Uptown Girl” singer initially postponed his concerts in March 2025 after undergoing unspecified surgery and physical therapy.

The surgery took place just weeks after the crooner lost his balance on Feb. 22, 2025, while performing “It’s Still Rock and Roll to Me” at the Mohegan Sun Arena in Uncasville, Conn.; however, it is unclear if the tumble and subsequent surgery were at all related to the NPH diagnosis he revealed to the public that May.

For now, Joel reports that he is “OK” and the diagnosis is “not that serious,” per his THR interview. Neurologists have warned the singer, however, about the risks involved in performing, including that the lighting and sound can cause stress in the body.

“And [neurologists] said, ‘Well, you really shouldn’t be doing that right now.’ So they have to test me further to see if I can go back and do performing again, which I would like to be able to do,” he said.

Times staff writer Alexandra Del Rosario and former assistant editor Christie D’Zurilla contributed to this report.