Some days your dad is sharp, chatty and completing the crossword. Other days he stares into space, can't follow a conversation, and tells you there's a child sitting in the corner of the room. He's also started shuffling when he walks, and your mum says he's been shouting and kicking in his sleep.
That combination of ups and downs, visual hallucinations, movement changes and restless sleep can be confusing for families, and for doctors too. It's also a pattern that can point to Lewy body dementia, often shortened to LBD.
This guide explains what LBD is, how it differs from Alzheimer's, how it's diagnosed and treated, and what helps day to day.
What Is Lewy Body Dementia?
Lewy body dementia is a type of dementia caused by abnormal deposits of a protein called alpha-synuclein inside nerve cells in the brain. These deposits are called Lewy bodies. The World Health Organization lists dementia with Lewy bodies among the main forms of dementia alongside Alzheimer's disease, vascular dementia and frontotemporal dementia.
"Lewy body dementia" is an umbrella term for two related diagnoses:
Dementia with Lewy bodies (DLB): thinking problems appear first, or around the same time as movement symptoms.
Parkinson's disease dementia: someone who has had Parkinson's disease for some time goes on to develop dementia.
Both involve the same underlying brain changes, and many of the symptoms overlap.
Common Symptoms
The National Institute on Aging describes a decline in thinking, especially in attention, visual perception, and planning and organisation. Over time, people also develop more distinctive symptoms, which may include:
Fluctuations in thinking, attention and alertness. Good periods and bad periods can swing within a day.
Visual hallucinations early in the illness, often detailed, such as seeing people or animals that aren't there.
Parkinson-like movement changes: slowness, stiffness, tremor or difficulty walking.
REM sleep behaviour disorder: physically acting out dreams by yelling, punching, kicking or falling out of bed.
More trouble with complex tasks, like multitasking and problem solving, than with memory, at least early on.
Alzheimers.gov adds other symptoms people may experience, including depression, anxiety, loss of interest, daytime sleepiness, sensitivity to heat and cold, dizziness and a poor sense of smell.
How It Differs from Alzheimer's
Alzheimer's usually starts with memory problems, particularly remembering recent events. LBD often starts differently, with changes in attention, visual perception, alertness, movement or sleep, while memory may be relatively preserved at first.
The NIA notes that dementia with Lewy bodies is often hard to diagnose because early symptoms can look like Alzheimer's or a psychiatric illness. Some people also have both Alzheimer's and Lewy body changes, which is one reason diagnosis can be tricky. Our guide to the difference between dementia and Alzheimer's explains how the main types relate.
What Causes It?
Researchers don't yet fully understand why Lewy bodies form. The National Institute of Neurological Disorders and Stroke notes that some conditions, particularly REM sleep behaviour disorder and loss of smell, are linked to a higher risk of LBD. Having a relative with LBD may increase risk, but it's not usually considered a hereditary disease. Age is the biggest risk factor.
How Is It Diagnosed?
There's no single test. Diagnosis usually involves:
a detailed history of symptoms, often with input from family
memory and thinking tests
a neurological exam looking at movement
blood tests and brain scans to rule out other causes
sometimes a sleep study, or specialised scans in some settings
Because symptoms overlap with Alzheimer's, Parkinson's and some psychiatric conditions, it's worth seeing a specialist, such as a neurologist, geriatrician or memory clinic, who has experience with LBD.
Keeping a simple diary of symptoms helps a lot here. Note when good and bad periods happen, any hallucinations, falls or sleep disturbances. Fluctuations are easy to miss in a short appointment. Our step-by-step guide to memory assessments explains what to expect.
Treatment and the Medication Warning Every Family Should Know
There's no cure for LBD, but treatments can help manage symptoms. According to the NIA's treatment guidance, options may include medicines for thinking and hallucinations, carefully managed medication for movement symptoms, and clonazepam or melatonin for REM sleep behaviour disorder. Physical, occupational and speech therapy can also help.
The most important thing to know: people with LBD can have severe reactions to antipsychotic medications. The NIA lists side effects including increased confusion, worse parkinsonism, extreme sleepiness and low blood pressure that can cause fainting. Some effects can be permanent. It advises that typical antipsychotics such as haloperidol generally should not be prescribed for people with LBD.
This matters most in emergencies. The NINDS suggests caregivers tell hospital staff about the LBD diagnosis and medication sensitivities, and ask that the person's neurologist be consulted before any medication is given for behaviour changes. Many families carry a card or letter with this information.
Fluctuations are one of the hardest parts of LBD to describe to a doctor. Elli Cares daily check-ins let someone record how they're feeling each day, and family in the care circle can add observational notes about good days, hard days, hallucinations or sleep. A downloadable GP report brings it together for appointments. Medication reminders can also help keep complex schedules on track.
Caring for Someone with LBD
LBD brings some particular challenges. These approaches can help:
Plan around fluctuations. Schedule important tasks and appointments for the person's better times of day, and allow for "off" days without treating them as failure.
Respond calmly to hallucinations. If a hallucination isn't frightening, it may not need challenging. If it is distressing, reassure, move to a different room or improve the lighting. Tell the doctor about any new or upsetting hallucinations.
Reduce fall risk. Movement changes, dizziness and fluctuating attention all raise fall risk. See our guide to fall prevention tools.
Keep the bedroom safe. For REM sleep behaviour disorder, move sharp furniture away from the bed and consider whether a bed partner should sleep separately for safety. Our article on dementia and sleep has more.
Keep routines steady. Familiar routines, familiar people and calm environments help. Our guide to daily routines for people with early dementia is a starting point.
Look after yourself. LBD can be especially demanding for carers. Connect with others who understand. The Lewy Body Dementia Association and the Alzheimer's Association both offer information and support, and our guide to caregiver support groups explains what they offer.
Frequently Asked Questions
What are the first signs of Lewy body dementia?
Early signs can include fluctuating attention and alertness, visual hallucinations, movement changes like slowness or stiffness, acting out dreams during sleep, and difficulty with planning and complex tasks.
How is Lewy body dementia different from Alzheimer's?
Alzheimer's usually starts with memory loss. LBD more often starts with changes in attention, alertness, visual perception, movement or sleep, and hallucinations are more common early on.
Why are antipsychotics dangerous in Lewy body dementia?
People with LBD can have severe reactions, including worse confusion, stiffness, extreme sleepiness and fainting. Some typical antipsychotics generally should not be prescribed. Always tell doctors and hospital staff about an LBD diagnosis.
Is Lewy body dementia hereditary?
It's not usually considered hereditary, although having a family member with LBD may slightly increase risk.
Knowledge Makes a Difference
LBD is less well known than Alzheimer's, which means families often become the people who explain it to others. Understanding the symptoms and the medication risks is one of the most protective things you can do. To see how Elli supports families day to day, visit our Seniors and Families page.
