Lewy body dementia is one of the most common types of dementia, but many people don’t know about it and it is often misdiagnosed.

Lewy body dementia is one of the most common types of dementia, affecting approximately 1.4 million Americans.
But many people still do not know much about the disease or its symptoms.
Now that might change after CNN founder and media giant Ted Turner recently told “CBS Sunday Morning” about his diagnosis of Lewy body dementia.
While more than a million people have the disease, getting the right diagnosis can be difficult.
Actor Robin Williams was diagnosed with the disease posthumously.
The symptoms of Lewy body dementia overlap with Alzheimer’s disease and Parkinson’s disease, which makes it difficult to diagnose correctly. Symptoms like hallucinations may also be misdiagnosed as other psychiatric disorders such as schizophrenia.
Complicating diagnosis, Lewy body dementia can occur alongside other brain disorders, including Alzheimer’s disease.
The disease gets its name from abnormal deposits in the brain known as Lewy bodies. These are made of a protein called alpha-synuclein which affects chemicals in the brain, causing problems with thinking, behavior, mood, and movement.
Lewy body dementia is an umbrella term for two related diagnoses — dementia with Lewy bodies and Parkinson’s disease dementia.
Both are caused by the buildup of Lewy bodies in the brain. These can only be seen after death during an autopsy.
Dr. Irene Litvan, a professor of neurosciences and director of the UC San Diego Health Movement Disorders Center, said there is disagreement among some doctors about whether dementia with Lewy bodies is part of the “spectrum of Parkinson’s disease” or if it is a separate disorder.
In dementia with Lewy bodies, people first show signs of a decline in thinking ability.
This can look like Alzheimer’s disease, but early on, people are more likely to have trouble with executive functioning than with memory. Executive tasks include abilities such as planning, multitasking, sequencing, and conceptualizing thoughts.
The main features that distinguish dementia with Lewy bodies from other conditions are:
- visual hallucinations, not caused by medications or other drugs
- fluctuations in alertness, attention, and mental abilities
- slowness of movement, difficulty walking, tremor, or stiffness — this is known as parkinsonism
- REM sleep behavior disorder, in which people “act out” their dreams by talking, yelling, kicking, and other movements
The fluctuations are “very typical of this disease,” said Litvan. “Sometimes a person can act almost normal, but other times they look like they are completely confused.”
Robin Williams’ family only learned that he had a severe case of the disease after his death by suicide in 2014.
In an editorial published in 2016 in the journal Neurology, Robin Williams’ wife Susan Schneider Williams wrote, “I experienced my brilliant husband being lucid with clear reasoning 1 minute and then, 5 minutes later, blank, lost in confusion.”
In contrast, Parkinson’s disease dementia starts as a movement disorder (parkinsonism), with later dementia and changes in mood and behavior.
“Dementia occurs five [times more] in Parkinson’s disease than in the general population,” said Litvan, “but it is usually a late event.”
However, not everyone with Parkinson’s disease develops dementia.
Litvan added that the distinction between when one of these diagnoses ends and the other begins is somewhat “arbitrary.”
According to the nonprofit Lewy Body Dementia Association, Lewy body dementia affects about 1.4 million Americans. It usually
Symptoms are typically mild early on and then can dramatically worsen over time.
“It’s a clear change from what people were before, socially or at work,” said Litvan. “They could do many things before, but they cannot anymore.”
People may have difficulty managing their bank accounts, taking their medications, planning for their day, or running errands.
In the later stages, the decline in a person’s thinking and movement abilities may be so great that they rely entirely on others to care for them.
On average, the disease lasts 5 to 8 years from diagnosis until death, but this can range from 2 to 20 years.
There is currently no cure for Lewy body dementia, but some medications are used to treat the symptoms of the disease.
This includes cholinesterase inhibitors to treat cognitive symptoms, levodopa (a Parkinson’s medication) for movement symptoms, and an antipsychotic medication for hallucinations.
Some doctors believe that people with Lewy body dementia respond better to cholinesterase inhibitors than people with Alzheimer’s disease do.
“The good thing for dementia with Lewy bodies is that in general, people respond much better to medications for cognition,” said Litvan.
Research is ongoing to find better ways to diagnose and treat Lewy body dementia. Some of this work is being done by a consortium of universities funded by the U.S. National Institutes of Health.
Litvan said one of the challenges in finding treatments for Lewy body dementia is the fluctuations in symptoms. If a person taking a new drug improves, is it because the drug is working or are they just having a “good day?”
She said because of that, many researchers are focusing right now on finding better ways to monitor how far along the disease is.