Lewy body dementia

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.