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Lewy body dementia (LBD) is an umbrella term for two similar and common subtypes of dementia: dementia with Lewy bodies (DLB) and
Parkinson's disease dementia (PDD). As of 2014, they were more often misdiagnosed than any other common dementia.<!-- Walker2015 --> Known as Lewy bodies (discovered in 1912 by Frederic Lewy) and Lewy neurites, these clumps affect both the central nervous system and the autonomic nervous system. The fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) gives Lewy body disease as the causative subtype of dementia with Lewy bodies, and Parkinson's disease as the causative subtype of Parkinson's disease dementia. The Lewy body dementias—dementia with Lewy bodies (DLB), and Parkinson's disease dementia (PDD)—are distinguished by the timing when cognitive and motor symptoms appear. The two Lewy body dementias are often considered to belong on a spectrum of Lewy body disease that includes Parkinson's disease.
A genetic architecture that predisposes an individual to some disease phenotypes is found in Parkinson's disease and the Lewy body dementias. The presence of Lewy bodies is a link between these disorders; the term "diseases with Lewy bodies" therefore may be more accurate than "Lewy body disease".
Cause and mechanisms
Dementia with Lewy bodies and Parkinson's disease dementia are similar in many ways, suggesting there may be a common pathophysiological mechanism, with PDD and DLB at opposite ends of a Lewy body disease spectrum, Lewy bodies and neurites have been found to develop from the aggregation of misfolded alpha-synuclein, a protein thought to assist in neurotransmitter release and vesicle turnover; whether these misfolded proteins are responsible for the neurodegenerative effects remains unclear, and no definitive link between Lewy bodies and neurodegenerative effects has been found. DLB is marked by the presence of Lewy bodies primarily in the cortical regions, and PDD with Lewy bodies primarily in the subcortical basal ganglia.
Despite differences in the timing of the appearance of symptoms, the two dementias "show remarkably convergent neuropathological changes at autopsy".
Diagnosis
Dementia with Lewy bodies and Parkinson's disease dementia have similar neuropathological features, but these features are highly variable and the conditions cannot be distinguished on pathological features alone. Generally, dementia with Lewy bodies is distinguished from Parkinson's disease dementia by the time frame in which dementia symptoms appear relative to parkinsonian symptoms and is diagnosed when cognitive symptoms begin before or at the same time as parkinsonism. Parkinson's disease dementia is the diagnosis when Parkinson's disease is already well established before the dementia occurs.<!-- Page v --> Hershey (2019) says, "DLB is the third most common of all the neurodegenerative diseases behind both Alzheimer's disease and Parkinson's disease".<!-- Page 309 --> As of 2014, the Lewy body dementias affect about 1.3 million people in the US and 140,000 in the UK.
LBD usually develops after the age of 50.
Society and culture
Advocacy and awareness
As of 2014, the Lewy body dementias were more often misdiagnosed than any other common dementia. and according to his widow, Susan Schneider Williams, he experienced depression, anxiety, and increasing paranoia. Upon autopsy, his widow said he was found to have diffuse Lewy body disease, while the autopsy used the term diffuse Lewy body dementia. Dennis Dickson, a spokesperson for the Lewy Body Dementia Association, clarified the distinction by stating that diffuse Lewy body dementia is more commonly called diffuse Lewy body disease and refers to the underlying disease process. According to Dickson, "Lewy bodies are generally limited in distribution" in early Parkinson's disease, while in dementia with Lewy bodies, "the Lewy bodies are spread widely throughout the brain, as was the case with Robin Williams."
The British author and poet Mervyn Peake died in 1968 and was diagnosed posthumously as a probable case of DLB in a 2003 paper published in JAMA Neurology. Sahlas said his death was "variously ascribed to Alzheimer disease, Parkinson disease, or postencephalitic parkinsonism". Nicholas King, a US actor and horticulturist, actress Dina Merrill, Donald Featherstone, who created the plastic pink flamingo, American radio and television host Casey Kasem, Canadian singer Pierre Lalonde, graphic artist/film set designer Ron Cobb, American actor Frank Bonner, Canadian musician and actor André Gagnon, Mark Volman, founding member of the band the Turtles, and American writer and artist Sam Kieth, co-creator of The Sandman and The Maxx.
British author Michael Bywater died of LBD.
Individuals from industry or government who have or died from LBD include Seymour Berry, US Director of the Bureau of Engraving and Printing, Los Angeles Times publisher Otis Chandler, Philip J. Rock,
a US Democratic politician of the Illinois Senate, U.S. media mogul and philanthropist Ted Turner, and Indian-born British billionaire S. P. Hinduja.
Arnold R. Hirsch, an American historian who taught at the University of New Orleans, and Jessie Isabelle Price, an American veterinary microbiologist, died from LBD.
In the sports realm, Jerry Sloan, American professional basketball player and coach, died from LBD. Major League Baseball players Tom Seaver, Andy Carey, and Bill Buckner died of LBD. Stan Mikita, Canadian ice hockey player, was diagnosed with possible LBD, but a post-mortem brain autopsy found that he had chronic traumatic encephalopathy.
In popular culture
Robin's Wish, a documentary exploring Robin Williams's Lewy body disease and how it contributed to his death, was released in September 2020.
Sleepwalk with Me is a book, one-man comedy, and film about a young man with relationship problems and RBD, a precursor to synucleinopathy, including LBD.