What Is Lewy Body Dementia?
Lewy body dementia is associated with abnormal deposits of a protein called alpha-synuclein in the brain. These deposits, known as Lewy bodies, disrupt the way brain cells work and communicate. Lewy body dementia is an umbrella term that covers two closely related conditions on the same disease spectrum: dementia with Lewy bodies, in which thinking problems appear first or around the same time as movement problems, and Parkinson's disease dementia, in which a person with established Parkinson's disease later develops dementia. The distinction depends mainly on which symptoms came first, and the two conditions share many of the same features.
What Are the Main Symptoms?
Clinicians look for four core clinical features when considering dementia with Lewy bodies:
- Fluctuating cognition and alertness: the person may be fairly clear one day, or even one hour, and markedly confused, drowsy or staring the next. These ups and downs are a hallmark of the condition.
- Recurrent, well-formed visual hallucinations: seeing people, animals or objects that are not there, often described in detail.
- REM sleep behavior disorder: physically acting out dreams during sleep, sometimes years before other symptoms begin.
- Spontaneous Parkinsonism: movement changes similar to Parkinson's disease, such as slowed movement, stiffness or rigidity, a shuffling walk or tremor.
Not every patient has every feature
A person does not need all four features to have Lewy body dementia. Some people mainly show fluctuations and hallucinations, while others first come to attention because of movement or sleep problems. Keeping notes about which symptoms appear, and when, helps the clinician see the pattern.
How Is Lewy Body Dementia Different from Alzheimer's Disease?
In early Alzheimer's disease, memory loss is usually the first and most prominent problem. In Lewy body dementia, early difficulties more often involve attention, alertness, judgment and visuospatial skills, such as judging distances or navigating familiar spaces, while memory may be relatively preserved at first. Detailed visual hallucinations, dramatic day-to-day fluctuations and Parkinson-like movement changes appear earlier and more often in Lewy body dementia than in Alzheimer's disease. The two conditions can also overlap: many older adults have both Lewy body and Alzheimer's changes in the brain, which is one reason a careful clinical evaluation matters.
What Is REM Sleep Behavior Disorder?
During normal REM (dreaming) sleep, the body is temporarily paralyzed. In REM sleep behavior disorder, that paralysis is incomplete, so a person may talk, shout, kick, punch or move around while acting out dreams. Bed partners are often the first to notice. Because these movements can lead to falls or injury, it is important to make the sleep area safer, for example by padding sharp furniture corners, moving breakable objects away from the bed and, in some cases, placing the mattress closer to the floor. A clinician should evaluate these symptoms, both for safety and because they can be an early sign of Lewy body disease.
How Is Lewy Body Dementia Diagnosed?
There is no single routine blood test that definitively diagnoses Lewy body dementia. Diagnosis is based on the clinical picture: a detailed history, including what family members and caregivers have observed, cognitive testing and a neurologic examination. Brain imaging and other selected tests may support the diagnosis or help rule out other causes, and a sleep study is sometimes used to confirm REM sleep behavior disorder. Because symptoms overlap with Alzheimer's disease, Parkinson's disease and medication side effects, evaluation by a clinician experienced with dementia is especially valuable.
How Is Lewy Body Dementia Treated?
There is no cure, but treatment can meaningfully improve symptoms and quality of life. Care focuses on symptom management and caregiver support:
- Cholinesterase inhibitors, such as donepezil or rivastigmine, often help with thinking, attention, hallucinations and fluctuations.
- Parkinsonian movement symptoms are managed carefully, since standard Parkinson's medicines can sometimes worsen hallucinations or confusion.
- Sleep problems, including REM sleep behavior disorder, can often be treated once they are recognized.
- Physical activity, physical therapy and fall-prevention measures help maintain mobility and safety.
- Depression and anxiety are common and treatable.
A critical medication warning
People with Lewy body dementia can have severe sensitivity to antipsychotic medications, particularly traditional dopamine-blocking agents. These drugs can cause dangerous worsening of stiffness, confusion, sedation and other serious reactions in this condition. Medication choices require specialist supervision, and families should make sure every prescriber knows about the Lewy body dementia diagnosis. Never stop a prescribed medication abruptly; instead, raise concerns with the prescribing clinician.
What Should Illinois Families Know?
- Recognize fluctuations: keep a simple log of good periods and confused periods to share with the clinician.
- Document hallucinations and sleep behaviors, including what the person saw or did and how often it happens.
- Prevent falls with good lighting, clear walkways, grab bars and a review of balance and mobility.
- Review all medications regularly with a clinician who knows about the Lewy body dementia diagnosis.
- Seek caregiver support early through education programs, support groups and local aging resources.
- Arrange an evaluation by a qualified clinician, ideally one experienced with dementia and movement disorders.
Frequently asked questions
- Is Lewy body dementia the same as Parkinson's disease?
- No, but they are related. Both involve alpha-synuclein deposits in the brain. Parkinson's disease begins with movement symptoms, while Lewy body dementia involves early cognitive decline. When dementia develops in someone with established Parkinson's disease, it is called Parkinson's disease dementia.
- Do all patients with Lewy body dementia experience hallucinations?
- No. Visual hallucinations are common and are a core feature, but not every person with Lewy body dementia has them.
- Can Lewy body dementia cause memory loss?
- Yes, although memory problems often appear later than in Alzheimer's disease. Early difficulties more often involve attention, alertness, problem-solving and visuospatial skills.
- Is Lewy body dementia curable?
- There is no cure, but medications and supportive care can help manage symptoms, improve quality of life and support caregivers.
- Why can antipsychotic medications be dangerous in Lewy body dementia?
- People with Lewy body dementia can have severe sensitivity to dopamine-blocking antipsychotic drugs, which may cause serious worsening of movement, confusion and sedation. Any such medication should be used only under specialist supervision.
Finding Alzheimer's and Dementia Support in Illinois
Families often benefit from memory evaluations, caregiver education, community support programs, dementia care planning and local aging and caregiver resources. These pages can help you get started:
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Explore Illinois Dementia Guide for information about dementia symptoms, diagnosis, treatment options, and resources for families and caregivers. Watch additional educational videos as they become available in our dementia video library.
This website provides educational information and does not replace individualized medical evaluation, diagnosis, or treatment. Medication decisions for Lewy body dementia require supervision by a qualified clinician. Do not stop prescribed medications abruptly. If you believe someone is experiencing a medical emergency, call 911.