What Is Lewy Body Dementia?

It’s the third most common form of dementia, but most people have never heard of Lewy body dementia.

When the 79-year-old media mogul Ted Turner revealed during a TV interview in late September 2018 that he hadLewy body dementia, it was probably the first time many viewers had heard of this disease.

“It’s a mild case of what people have as Alzheimer’s.It’s similar to that, but not nearly as bad,” Turner told the journalist Ted Koppel during the interview forCBS Sunday Morning. (1)

“Alzheimer’s is fatal. Thank goodness I don’t have that. But I also have got … let’s … I can’t remember the name of it.”

“That’s all right,” said Koppel. “Tell me what the …”

“That’s dementia.I can’t remember what my disease is!” Turner said, laughing.

“It’s an unpleasant thing to remember,” said Koppel.

“You bet,” said Turner.

Lewy Body Dementia Affects at Least 1.4 Million Americans and Probably More

Turner was not exactly correct when he described Lewy body dementia as a milder form ofAlzheimer’s disease.

So what is it?

Lewy body dementia is a progressive brain disease affecting an estimated 1.4 million people in the United States. (2)

医学专家通常认为它是third most common form of dementia, following Alzheimer’s (the leading cause) and vascular dementia.

But experts believe Lewy body dementia may be widely underdiagnosed because some of its symptoms resemble those ofAlzheimer’s disease,Parkinson’s disease, or psychiatric disorders likeschizophrenia.

Researchers have also begun to recognize that many people diagnosed with Alzheimer’s disease may also have Lewy body dementia, vascular dementia, or all threeforms of dementiasimultaneously — a condition called mixed dementia.

As with other types of dementia,Lewy body dementia causessevere loss of cognitive ability that interferes with a person’s everyday activities.

Researchers are working to better understand why some people develop Lewy body dementia.

They do know that this disease typically affects men and women over age 50. Other risk factors include having Parkinson’s disease or a condition calledREM(rapid eye movement) sleep behavior disorder. (3)

REM sleep behavior disorder causes people to physically act out vivid, sometimes violent dreams — sometimes yelling, flailing, or punching bed partners — while they remain asleep.

Lewy body dementia is not considered a genetic illness (with the exception of a very small number of cases linked to mutation), but having a relative with the disease seems to increase risk.

Inside the Brain of a Person With Lewy Body Dementia

Like Alzheimer’s disease, Lewy body dementia is caused by abnormal protein deposits in the brain. WhileAlzheimer’s is linked to tau and amyloid proteins, Lewy body dementia is associated with a protein called alpha-synuclein. (4)

In a healthy person,alpha-synuclein helps neurons(brain cells)communicateby producing chemicals calledneurotransmitters, including two key ones:acetylcholineanddopamine.

But when alpha-synuclein begins to accumulateinside neurons,forming clumps calledLewy bodies, neurons no longer function adequately and begin to die.

This impacts thinking, memory, behavior, sleep, mood, and movement.

There are two forms of Lewy body dementia, both characterized by the presence of Lewy bodies in the brain:

• Dementia with Lewy bodies
• Parkinson’s disease dementia

Dementia with Lewy bodies typically begins with cognitive symptoms, while Parkinson’s disease dementia generally starts with physical symptoms.

Over time, however, people with either condition begin to show the same constellation of symptoms.

Lewy bodies are named forFriedrich Lewy, an eminentGerman-born neurologist. In 1912, he discovered theabnormal proteindeposits now called Lewy bodies in the brains of people with Parkinson’s disease.

Symptoms of Lewy Body Dementia May Overlap With Those of Alzheimer’s or Parkinson’s Disease

With Alzheimer’s, short-termmemory lossis a signature trait of the disease, especially in its early stages.

For people with Lewy body dementia, memory issues may not be among the first symptoms but they may develop as the disease progresses.

TheLewy Body Dementia Associationcalls this a “multi-system disease” because it affects so many different parts of the brain and body.

Symptoms may include:

• Visualor otherhallucinations, which occur in up to 80 percent of patients, often early on; these may include seeing shapes, animals, or people that aren’t there.
• Periods of alertness and confusion that can fluctuate significantly from hour to hour or day to day; there may be episodes of drowsiness, long periods of staring into space, or disorganized speech.
• Movement disorders that resemble symptoms of Parkinson’s such as slowed movement, rigid muscles, tremor, or a shuffling walk
• Acting out dreams while still asleep
• Problems withautonomic nervous systemfunction, resulting in dizziness, poor body-temperature control, difficulty swallowing,incontinence, orconstipation
• Depression
• Apathy (3)

Medications Can Help Make Symptoms More Tolerable

As with Alzheimer’s, there is currently no cure for Lewy body dementia.

After the onset of symptoms, people with this disease live for 5 to 8 years, on average, although those numbers can also range from 2 to 20.

Drugs can slow the progression of this disease somewhat and make symptoms more bearable.

Many of these medications have been approved by the U.S. Food and Drug Administration (FDA) for thetreatment ofAlzheimer’s disease, with clinical evidence that they can also help people with other forms of dementia.

路易体痴呆患者可能会发现一些relief from taking cholinesterase inhibitors — which includeAricept (donepezil),Razadyne (galantamine), andExelon (rivastigmine)—which help Alzheimer’s patients with memory loss, confusion, and problems with thinking and reasoning. (5)

In fact, patients with Lewy body dementia may have a better response to these drugs than Alzheimer’s patientstypically do.

Cholinesterase inhibitors may also help reduce hallucinations and delusions, although doctors warn the drugs take time to kick in, can cause side effects like nausea, and aren’t always effective.

The FDA has approved a single Alzheimer’s drug,Exelon, to treatParkinson’s disease dementia. While it can boost cognitive function, it, too, has side effects.

For Lewy bodydementia patientshaving movement-related symptoms, doctors may recommend a Parkinson’s medication calledcarbidopa-levodopa (Sinemet, Parcopa, Stalevo). But because of serious side effects, like hallucinations and delusions, physicians prescribe this drug with caution.

Klonopin (clonazepam), a drug used for seizures andpanic attacks, can reduce REM sleep behavior disorder at very low doses. Side effects can include dizziness, unsteadiness, and cognitive problems.

The sleep hormonemelatoninmay also help, on its own or in combination withclonazepam.

Physicians sometimes prescribe so-called atypicalantipsychoticdrugs — such asSeroquel (quetiapine)andClozaril (clozapine)— to treat hallucinations, delusions, agitation, and other behavioral symptoms. (6) But the evidence for these drugs is both limited and mixed, with some studies showing effectiveness and others ineffectiveness. The drugs can also cause side effects that may reduce quality of life or cause additional medical problems. (7)

Traditional (typical) antipsychotic medication can be dangerous for people with Lewy body dementia. Drugs such asHaldol (haloperidol)can result in severe confusion, extremeParkinsonism, sedation, and even death.

This potentially life-threatening response makes accuratediagnosis of Lewy body dementiaeven more critical.