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Lewy body dementia, also known as dementia with Lewy bodies (LBD), stands as the second most common form of dementia after Alzheimer’s disease. This condition is characterized by the formation of protein clusters called Lewy bodies within nerve cells of the brain, particularly impacting regions associated with cognition, memory, and movement. Over time, LBD leads to a progressive decline in mental abilities. It may manifest with visual hallucinations, changes in alertness, and even Parkinson’s–like symptoms such as muscle rigidity, slow movements, walking difficulties, and tremors.
While LBD primarily affects individuals over 65, its symptoms can resemble those of other neurological disorders like Alzheimer’s and Parkinson’s disease. Unfortunately, there is no cure for LBD, but there are management options available. Medications can help alleviate some symptoms, and nonmedical therapies like physical and speech therapy can also provide valuable support for individuals and their loved ones dealing with this challenging condition.
Symptoms
Lewy body dementia can lead to a range of symptoms, including:
- Visual hallucinations: People with Lewy body dementia often experience regular visual hallucinations, where they see things that aren’t actually there. These hallucinations can involve shapes, animals, or people. Sometimes, they might also hear, smell, or feel things that aren’t real.
- Movement issues: This condition can cause movement problems similar to Parkinson’s disease. These may include slow movements, stiff muscles, trembling, or difficulty walking, which can increase the risk of falls.
- Problems with automatic functions: Lewy body dementia can affect the autonomic nervous system, which controls automatic bodily functions like blood pressure, heart rate, sweating, and digestion. This can lead to issues such as sudden drops in blood pressure upon standing, dizziness, falls, loss of bladder control, and constipation.
- Sleep troubles: Many individuals with Lewy body dementia experience a sleep disorder called REM sleep behavior disorder. This condition makes people physically act out their dreams while asleep, leading to actions like punching, kicking, yelling, or screaming during sleep.
- Varying attention: Individuals with this condition may have periods of drowsiness, extended periods of staring into space, frequent daytime naps, or difficulties with organized speech.
- Mood changes: Depression can develop in people with Lewy body dementia, leading to feelings of sadness and hopelessness.
- Cognitive problems: Cognitive problems are common in Lewy body dementia, resembling those seen in Alzheimer’s disease. These issues may involve confusion, difficulty concentrating, problems with spatial awareness, and memory loss.
- Apathy: A loss of motivation and interest in activities may also occur.
In summary, Lewy body dementia can manifest through various symptoms, including visual hallucinations, movement problems, issues with automatic bodily functions, cognitive challenges, sleep disturbances, fluctuating attention, mood changes, and apathy. Understanding these symptoms can help in early diagnosis and appropriate care.
Causes
Lewy body dementia (LBD) and Parkinson’s disease dementia both result from the buildup of Lewy bodies, protein clumps in the brain. The exact causes of LBD are unclear but may involve a mix of genetics, environment, and aging. Recent research found genetic risk factors in APOE and GBA genes, which can increase the risk of LBD, but such genetic causes are rare. Most cases of LBD are not inherited.
Risk factors
Several factors may increase one’s risk of developing Lewy body dementia, such as:
- Age: This condition commonly affects people over the age of 60.
- Sex: Men are at a higher risk of Lewy body dementia than women.
- Family history: The likelihood of having LBD is increased by a family history or having a family member with the condition and Parkinson’s disease.
Diagnosis
Lewy body dementia, also known as dementia with Lewy bodies (DLB), is characterized by a gradual decline in cognitive function, along with at least two of the following symptoms:
- Varying alertness and thinking function.
- Repeated visual hallucinations.
- Parkinsonian symptoms.
- Rapid eye movement (REM) sleep behavior disorder, in which people act out their dreams during sleep.
- Autonomic nervous system problems, resulting in difficulties regulating blood pressure, heart rate, body temperature, and sweating.
Sensitivity to medications that treat psychosis, such as haloperidol, also supports a diagnosis. However, antipsychotic medications are typically avoided for people with Lewy body dementia because they can exacerbate symptoms.
Diagnosing Lewy body dementia involves a combination of the following tests and evaluations:
- Neurological and physical examination: This includes assessing reflexes, strength, balance, and eye movements to check for signs of related conditions like Parkinson’s disease.
- Assessment of mental abilities: A brief cognitive assessment evaluates memory and thinking skills, though it may not specifically distinguish between Lewy body dementia and Alzheimer’s disease. More extensive assessments over several hours can help identify Lewy body dementia.
- Blood tests: These are conducted to rule out physical problems that can impact brain function, such as vitamin B–12 deficiency or an underactive thyroid gland.
- Brain scans: Magnetic resonance imaging (MRI) or computed tomography (CT) scans are used to identify brain abnormalities such as strokes or tumors. Dementia–related features on these scans can suggest different types of dementia, including Alzheimer’s or Lewy body dementia. More specific imaging studies like fluorodeoxyglucose PET brain scans assess brain function, and single–photon emission computerized tomography (SPECT) or PET imaging can reveal reduced dopamine transporter uptake in the brain, aiding in Lewy body dementia diagnosis.
- Sleep evaluation: A polysomnogram examines sleep patterns, particularly to check for REM sleep behavior disorder. An autonomic function test can also identify signs of heart rate and blood pressure instability.
- Heart test: In some countries, healthcare professionals may order a heart test called myocardial scintigraphy to assess blood flow to the heart for indications of Lewy body dementia. However, this test is not used in the United States.
Ongoing research explores emerging biomarkers that may eventually enable early diagnosis of Lewy body dementia before the full disease develops.
Treatment
Lewy body dementia has no cure, but targeted treatments can improve symptoms.
Medications:
- Cholinesterase inhibitors: Drugs like rivastigmine, donepezil, and galantamine increase brain neurotransmitters, aiding memory and cognitive function. They may reduce hallucinations and behavioral issues. Side effects can include upset stomach, muscle cramps, and increased urination.
- Memantine: In moderate or severe cases, memantine may complement cholinesterase inhibitors. It’s an NMDA receptor antagonist.
- Parkinson’s disease medications: Carbidopa–levodopa can ease muscle rigidity and slow movement, but may also cause confusion, hallucinations, and delusions.
- Symptom–specific medications: Doctors may prescribe medications for sleep or movement problems. Avoid memory–worsening drugs like diphenhydramine and oxybutynin.
- Antipsychotic medications: These should be used cautiously due to potential worsening of symptoms. Second–generation antipsychotics like quetiapine or clozapine may be considered in rare cases.
Therapies:
- Behavioral approaches: Sometimes, tolerating hallucinations is better than dealing with medication side effects. Modify the environment by reducing clutter and noise, and avoid correcting or quizzing the person with dementia. Offer reassurance and validation.
- Daily routines: Simplify tasks, break them into smaller steps, and focus on successes. Implement structure and routines during the day to minimize confusion.
Remember to discuss the potential impact of any medications on memory with a healthcare professional and exercise caution with antipsychotic drugs due to their side effects.
