Dementia With Lewy Bodies May Be More Common in Older Adults Than Previously Thought, New Study Finds

What the Latest Research Reveals About This Often-Missed Condition

A new analysis of multiple studies suggests that dementia with Lewy bodies, a brain disorder that progresses faster than Alzheimer’s disease and causes greater daily disability, may be significantly underdiagnosed in older adults. Researchers found that this form of dementia becomes much more common as people age, especially after 65.

The study, published in JAMA Neurology, pooled data from 12 population-based studies around the world. It calculated that about 47 out of every 100,000 adults aged 65 and older develop dementia with Lewy bodies each year. Among this same age group, roughly 352 out of every 100,000 people are currently living with the condition.

For people younger than 65, the numbers were much lower. Only about 0.34 new cases per 100,000 people occur each year, and about 2.5 per 100,000 people have the disease at any given time.

The lead author of the study, Dr. Daniele Urso of the University of Bari Aldo Moro in Italy, explained that despite being considered the second most common degenerative dementia in older adults after Alzheimer’s, “we still know surprisingly little about how common it is at the population level.”

Why This Matters for You and Your Family

Dementia with Lewy bodies is not a rare condition, but it is frequently misdiagnosed. Many people with this disease are told they have Alzheimer’s or Parkinson’s disease instead. This can lead to treatments that do not work well or may even cause harm.

For example, some medications used for Alzheimer’s can worsen symptoms in people with Lewy body dementia. Antipsychotic drugs, sometimes given to manage hallucinations, can cause severe side effects in these patients. Getting the right diagnosis is critical for safe and effective care.

The study found that men had a slightly higher rate of developing this dementia than women. The incidence was 5.45 per 100,000 person-years in men compared to 4.32 in women.

Dr. Michael Okun, a neurologist at the University of Florida Fixel Institute who was not involved in the research, emphasized that recognizing the diagnosis early “can change care, safety, and quality of life for families.” He added that “awareness matters” because this condition is often overlooked.

Understanding Dementia With Lewy Bodies

Dementia with Lewy bodies gets its name from abnormal clumps of a protein called alpha-synuclein that build up in the brain. These clumps, known as Lewy bodies, damage brain cells over time. The disease affects both the outer layer of the brain (the cortex) and deeper brain regions.

The symptoms are different from Alzheimer’s in several important ways. People with Lewy body dementia often experience:

• Fluctuating cognition: Their ability to think clearly can vary dramatically from hour to hour or day to day. They may seem sharp one moment and confused the next.
• Recurrent visual hallucinations: Seeing things that are not there, such as people, animals, or patterns, is very common. These hallucinations are often detailed and can be disturbing.
• REM sleep behavior disorder: People act out their dreams physically, sometimes kicking, punching, or yelling while asleep.
• Spontaneous parkinsonism: Symptoms like stiffness, slow movement, tremors, and trouble walking appear without a known cause like Parkinson’s disease.
• Psychiatric symptoms: Depression, anxiety, and apathy are frequent.
• Autonomic dysfunction: Problems with blood pressure, digestion, bladder control, and temperature regulation can occur.

The disease tends to progress faster than Alzheimer’s, and patients often experience greater functional decline. This means they lose the ability to perform daily tasks more quickly.

The Challenge of Diagnosis

Diagnosing dementia with Lewy bodies is notoriously difficult. The symptoms overlap significantly with other neurodegenerative disorders, especially Alzheimer’s and Parkinson’s disease. This uncertainty can be extremely stressful for patients and their families.

A well-known example of this diagnostic struggle came from Susan Schneider Williams, the wife of actor and comedian Robin Williams. In an essay published in Neurology, she described how her husband had Lewy body disease before he died by suicide. His symptoms were initially mistaken for other conditions, which caused confusion and delayed proper care.

The researchers noted that the numbers in their study likely underestimate the true burden of the disease. They pointed out that many cases are missed in everyday medical practice due to underdiagnosis and a lack of sensitivity in current diagnostic tools.

“Lewy body dementia is more common than many people realize,” Dr. Okun stated. “The numbers likely underestimate the true burden because many cases are missed in everyday practice.” He called for “better recognition, better tools, and more conversations about symptoms like hallucinations, dream enactment, and fluctuating thinking.”

Comparing Lewy Body Dementia to Other Brain Disorders

This study found that dementia with Lewy bodies is actually more common than several other rare neurodegenerative diseases. The researchers compared their findings to published rates for other conditions:

• Frontotemporal dementia: about 2.28 new cases per 100,000 person-years
• Amyotrophic lateral sclerosis (ALS): about 1.59 per 100,000 person-years
• Progressive supranuclear palsy: about 0.81 per 100,000 person-years
• Corticobasal syndrome: about 0.28 per 100,000 person-years

The incidence of dementia with Lewy bodies in older adults (46.85 per 100,000 person-years) is substantially higher than all of these conditions. This reinforces that it is not a rare disorder in the aging population, even though it is often overlooked.

Limitations of the Current Research

The researchers acknowledged several limitations in their work. The meta-analysis included only a small number of studies, and there was high variability among them. The statistical measure of this variability, called I-squared, was 85% or higher, which means the studies differed significantly from each other.

This variability likely reflects the inherent challenges in diagnosing the disease. Changes in diagnostic criteria over time may also have influenced the results. For example, newer criteria might identify more cases than older ones.

Another important limitation is that most of the studies came from high-income countries. Dr. Urso emphasized that “we need more studies from different regions of the world, especially in underrepresented populations, to understand the true global burden of dementia with Lewy bodies.”

Practical Takeaways for Readers

If you or a loved one is experiencing symptoms that might suggest Lewy body dementia, here are some steps to consider:

• Seek a specialist evaluation: A neurologist or a geriatric psychiatrist with experience in movement disorders and dementia can provide the most accurate diagnosis. Ask specifically about Lewy body dementia if symptoms like hallucinations, sleep acting-out, or fluctuating thinking are present.
• Keep a symptom diary: Write down when symptoms occur, how long they last, and what seems to trigger them. This information can be very helpful for doctors.
• Discuss sleep behaviors: If you or your partner notices dream enactment, such as kicking or shouting during sleep, mention this to your doctor. REM sleep behavior disorder often appears years before other symptoms.
• Be cautious with medications: Some drugs used for Alzheimer’s or psychiatric conditions can worsen symptoms in Lewy body dementia. Always inform your doctor about all medications and supplements you take.
• Build a support network: Organizations like the Lewy Body Dementia Association offer resources, support groups, and educational materials for patients and caregivers.

What Experts Say About the Future

Dr. Okun stressed that this study serves as an important reminder. “We need better recognition, better tools, and more conversations about symptoms like hallucinations, dream enactment, and fluctuating thinking,” he said.

Dr. Urso and his team hope their findings will encourage more research and better healthcare planning. “Reliable estimates are also essential for healthcare planning,” he noted. “Dementia with Lewy bodies often requires a different clinical approach compared with other dementias, because patients may present with a complex combination of cognitive, motor, psychiatric, sleep, and autonomic symptoms.”

For now, the key message is clear: dementia with Lewy bodies is not rare in older adults. It is likely more common than current numbers show, and improving diagnosis could make a real difference in how patients live with the disease. Awareness among both doctors and the public is the first step toward better care.

Source: MedPage Today