There are more than a hundred types of dementia, all of which are caused by different changes in the brain. The most well-known is Alzheimer’s disease, caused by a build-up of the proteins amyloid and tau. Then there’s another protein called alpha-synuclein, which builds up into clumps called Lewy bodies, which cause other forms of dementia.
“The term ‘Lewy body dementia’ can be really confusing, because it’s actually an umbrella term for dementia with Lewy bodies and Parkinson’s disease dementia,” says UNC Health neurologist Hannah Noah, MD, MPH. “These two conditions are very similar, but the difference is the onset of cognitive symptoms relative to motor symptoms.”
The motor symptoms of Parkinson’s—tremor, stiffness, slowness—are caused by Lewy bodies in the brain stem; they reduce dopamine, a brain chemical, and affect movement. But if the Lewy bodies are in the parts of the brain responsible for memory and thinking, cognitive symptoms are more pronounced.
A person who starts to experience cognitive symptoms at least a year after the motor symptoms of Parkinson’s is diagnosed with Parkinson’s disease dementia, while a person who has certain cognitive symptoms is diagnosed with dementia with Lewy bodies. A diagnosis of dementia with Lewy bodies doesn’t always mean a person will develop the movement problems associated with Parkinson’s disease, though they may exhibit some of those motor symptoms.
Doctors still don’t know why this protein builds up and causes these symptoms, but they have learned more about distinguishing this type of dementia from others.
Symptoms of Lewy Body Dementia
Dementia with Lewy bodies has four key features, Dr. Noah says.
“Visual hallucinations are really specific to dementia with Lewy bodies,” she says. “You might see animals, pets, children, bugs. These hallucinations tend to be well-formed, as opposed to the abstract images you might see before a migraine.”
Abstract hallucinations tend to be colors, flashes, shapes and patterns, while the hallucinations associated with dementia with Lewy bodies are very realistic.
People with this dementia may also have an REM sleep disorder in which the body does not stay still during REM sleep; typically, the only part of the body that moves during that stage is the eyes.
“You may see someone acting out their dreams, punching the air or throwing themselves out of bed,” Dr. Noah says.
The third notable feature of dementia with Lewy bodies are the cognitive changes you might notice with other dementias, including difficulty paying attention or concentrating, unorganized thoughts, changes in judgment and memory and a sense that the person is out of it for parts of the day.
Last, if you have dementia with Lewy bodies you could have some motor symptoms, such as a tremor or slowness, but “it’s often more subtle than someone with Parkinson’s disease,” Dr. Noah says.
Again, if the motor symptoms show up first and are the only symptoms for at least a year, then you’d typically be diagnosed first with Parkinson’s disease, and then with Parkinson’s disease dementia.
Your doctor may make a diagnosis of dementia with Lewy bodies based on the presence of those four features. They may also order a skin biopsy or a spinal tap to draw cerebrospinal fluid; both can reveal the presence of abnormal alpha-synuclein.
“The biomarker testing can bolster confidence in the diagnosis, but if someone is having well-formed visual hallucinations, acting out their dreams and has those subtle motor symptoms, we can be pretty certain about dementia with Lewy bodies,” Dr. Noah says.
Treating Lewy Body Dementia
Like other dementias, Lewy body dementia has no cure. Treatment focuses on the symptoms you have and how much they bother you.
“With sleep disorders, we can use melatonin or clonazepam (Klonopin) to decrease your movements, but it’s also helpful to get a bed rail and keep sharp objects away from the bed,” Dr. Noah says.
For cognitive symptoms, your doctor may prescribe the same cholinesterase inhibitors used for treatment of Alzheimer’s disease; these medications work by stopping the enzymes that break down acetylcholine, a neurotransmitter that is important for memory. With more acetylcholine in the brain, people tend to have improved attention and reduced confusion.
If you’re experiencing bothersome motor symptoms, your doctor may do a trial of levodopa, the same medication used for Parkinson’s disease symptoms.
“For hallucinations, antipsychotics can be helpful, but we typically don’t treat unless these are bothering the person,” Dr. Noah says. “Once the person knows they’re hallucinating, these hallucinations are typically not disturbing or distressing.”
However, some antipsychotics shouldn’t be used because of the ways that Lewy bodies affect dopamine in your brain. This can be important to know if you end up in the emergency department.
“This is a disease where you are dopamine-deficient, and some of the antipsychotics used in emergency departments, like haloperidol (Haldol) work by blocking dopamine,” Dr. Noah says. “That can cause serious side effects, like an inability to move. I will usually add these medications to a patient’s allergy list, but it’s important to be aware of the risk.”
Symptoms will continue to progress.
“This type of dementia does move a little faster than Alzheimer’s disease, though it’s still years, not months,” Dr. Noah says, noting that it’s typically six to eight years from the time of diagnosis until death. “Connecting with dementia support programs can be really helpful for both the patient and their family.”
If you or a loved one are showing symptoms of dementia, talk to your doctor or find one near you.