The recent death of Ted Turner brought renewed attention to Lewy body dementia — the condition he had been living with for several years before his passing. Turner had spoken publicly about his diagnosis, and his death prompted many people to ask a question that is more common than it should be: what exactly is Lewy body dementia, and how is it different from Alzheimer's?
The honest answer is that most people — including, at times, the doctors treating it — don't fully understand it. Lewy body dementia is consistently underdiagnosed, underrecognized, and confused with other conditions. For families watching a loved one decline and trying to understand what they're facing, that confusion compounds an already painful situation. This article explains what the condition actually is, what distinguishes it, and what families and caregivers need to know.
What Lewy Body Dementia Is
Lewy body dementia is a progressive brain disorder caused by abnormal deposits of a protein called alpha-synuclein that accumulate inside neurons. These deposits are called Lewy bodies, named after the neurologist Friedrich Lewy, who first identified them in the early 20th century. As Lewy bodies spread through the brain, they disrupt normal function in the regions they affect — producing the cognitive, behavioral, physical, and autonomic symptoms that define the condition.
There are technically two related diagnoses under the Lewy body umbrella. Dementia with Lewy bodies (DLB) is diagnosed when cognitive symptoms appear before or at the same time as movement problems. Parkinson's disease dementia (PDD) is diagnosed when a person has had Parkinson's disease for at least a year before significant cognitive decline appears. The underlying pathology — Lewy body deposits — is the same in both. Clinicians distinguish them primarily by timing, and the practical distinction matters more for research classification than for families trying to understand what their loved one is experiencing.
How It Differs From Alzheimer's
Alzheimer's disease and Lewy body dementia can look similar in early stages — both involve memory problems, confusion, and progressive cognitive decline. But several features set Lewy body dementia apart, and recognizing them matters because the conditions are managed differently and respond differently to medications.
Fluctuating cognition. One of the most distinctive features of Lewy body dementia is that the person's clarity of thought varies significantly — not just day to day, but sometimes hour to hour. A person may seem relatively sharp in the morning and deeply confused by afternoon. They may have stretches of lucidity that give family members false hope, followed by episodes of profound disorientation. In Alzheimer's, cognitive decline is generally more gradual and consistent. In Lewy body dementia, the fluctuations are part of the disease itself, not simply good days and bad days.
Visual hallucinations. Detailed, recurrent visual hallucinations — often of people, children, or animals that the person can see clearly but that are not there — are a core feature of Lewy body dementia and occur in the majority of people with the condition. These hallucinations are typically not frightening at first; many patients describe them matter-of-factly. They are generated by the disease process, not by psychological disturbance, and they are one of the features most useful in distinguishing Lewy body dementia from Alzheimer's, where hallucinations are less common and tend to appear later.
Parkinsonism. Many people with Lewy body dementia develop movement symptoms similar to Parkinson's disease — tremor, rigidity, slowed movement, and a shuffling gait. These may be present from the beginning or develop as the disease progresses. The overlap with Parkinson's is one of the reasons Lewy body dementia is frequently misdiagnosed.
REM sleep behavior disorder. In healthy sleep, the brain paralyzes the body during REM (dreaming) sleep to prevent acting out dreams. In REM sleep behavior disorder, that paralysis fails — and the person physically acts out what they are dreaming, sometimes talking, shouting, kicking, or striking out. This can be dangerous to a bed partner and deeply disturbing to witness. Importantly, REM sleep behavior disorder can appear years or even decades before other symptoms of Lewy body dementia. It is increasingly recognized as an early warning sign.
Why It Gets Misdiagnosed So Often
Studies suggest the average time between the onset of symptoms and a correct Lewy body dementia diagnosis is one to two years — and many cases are never correctly identified during the patient's lifetime, with the diagnosis made only after death through autopsy. Several factors drive this.
The symptoms overlap significantly with Alzheimer's, Parkinson's, and psychiatric conditions. A person who comes to a doctor with memory problems and hallucinations may be diagnosed with Alzheimer's. A person with movement problems and cognitive changes may be diagnosed with Parkinson's. A person whose prominent early symptoms are the hallucinations or behavioral changes may be referred for psychiatric evaluation. Each of those is a plausible initial interpretation — and each misses the underlying condition.
The fluctuating nature of the disease also works against accurate diagnosis. A person who is relatively coherent at a clinic appointment may not present the degree of impairment their family has been observing at home. Physicians who see the patient only briefly may underestimate the severity of what is happening between appointments.
There is also simply less awareness of Lewy body dementia among both the general public and, in some cases, among primary care physicians. Alzheimer's has decades of public education behind it. Lewy body dementia does not.
A Critical Warning About Certain Medications
This is one of the most important things in this article, and it cannot be stated strongly enough: people with Lewy body dementia can have severe, potentially life-threatening reactions to certain antipsychotic medications.
When someone with Lewy body dementia develops hallucinations or behavioral disturbances, a physician who does not recognize the underlying diagnosis may prescribe a conventional antipsychotic — haloperidol, for example, or certain other medications in this class — to manage those symptoms. In a person with Lewy body dementia, these drugs can trigger a reaction called neuroleptic sensitivity: sudden and severe worsening of Parkinson-like symptoms, extreme rigidity, high fever, confusion, and rapid cognitive decline. In some cases it can be fatal.
This risk is the reason an accurate diagnosis matters so urgently. A family that knows their loved one has Lewy body dementia can ensure that any treating physician — including emergency room doctors who may not have access to the full medical history — knows about this sensitivity before any medication is prescribed.
If you are a caregiver for someone with Lewy body dementia, the Lewy Body Dementia Association recommends keeping written documentation of this medication sensitivity and carrying it to all medical appointments. In an emergency situation, the ability to quickly inform treating staff of this risk can be critical.
Other Symptoms to Know
Beyond the four core features above, Lewy body dementia can produce a range of other symptoms that reflect its effects on the autonomic nervous system — the part of the nervous system that regulates automatic body functions.
Orthostatic hypotension — a sudden drop in blood pressure when standing up — is common and can cause dizziness, fainting, and falls. This is a significant fall risk for older adults and one that caregivers should be alert to, particularly when helping someone transition from sitting to standing.
Urinary incontinence and constipation are frequent. Sensitivity to heat and cold and difficulty regulating body temperature can occur. Excessive daytime sleepiness — separate from the nighttime sleep disturbances — affects many patients.
Depression and anxiety are also common features of the disease and often appear early, sometimes before significant cognitive changes. These are not simply psychological reactions to the diagnosis; they are part of the neurological process itself.
What Progression Typically Looks Like
Lewy body dementia is a progressive condition with no cure. The rate of progression varies significantly from person to person, but the average survival after diagnosis is five to eight years, with a range from two to twenty. This is broadly similar to Alzheimer's, though the course of Lewy body dementia tends to involve a wider range of physical and behavioral symptoms alongside cognitive decline.
In earlier stages, the fluctuating cognition, hallucinations, and sleep disturbances are often the most prominent features, alongside the early motor symptoms if present. As the disease advances, mobility typically decreases, swallowing difficulties can develop, and the degree of cognitive impairment increases. Full-time care is generally required in later stages.
One thing worth understanding: because of the day-to-day fluctuations that are characteristic of the disease, caregivers sometimes experience a particularly difficult emotional cycle — a period of relative clarity that feels like improvement, followed by a sharp decline back. This is the disease, not a meaningful recovery. Recognizing the fluctuating pattern for what it is can help families set realistic expectations and make better care decisions.
For Caregivers: What Helps
Caring for someone with Lewy body dementia is among the most demanding caregiving situations because of the combination of cognitive, behavioral, physical, and autonomic symptoms — often in a person who may have periods of awareness about what is happening to them.
On the hallucinations: The standard advice for managing hallucinations in Lewy body dementia is not to argue or insist the hallucination isn't real, but also not to play along in a way that increases the person's distress. Many patients are not frightened by the hallucinations — they simply report them. When distress does occur, redirecting attention or changing the environment is generally more effective than confrontation. Reducing clutter and improving lighting can sometimes reduce the frequency and intensity of visual hallucinations.
On fall prevention: The combination of Parkinsonism and orthostatic hypotension creates significant fall risk. Grab bars, non-slip surfaces, removing floor rugs, and careful assistance when the person is changing position are all important. Slow transitions from lying to sitting to standing — pausing at each position to allow blood pressure to stabilize — can reduce fainting episodes.
On sleep: Keeping the sleeping environment safe for someone who may act out dreams is important. This may mean separate sleeping arrangements for a bed partner, padding around the bed, or other modifications depending on the severity of REM behavior disorder.
On the medical team: Ideally, someone with Lewy body dementia should be seen by a neurologist with specific experience in movement disorders or dementia — and preferably one familiar with Lewy body disease specifically. A geriatric psychiatrist may be involved for behavioral symptom management. The Lewy Body Dementia Association's website maintains a directory of LBD specialists and can help connect families with appropriate care.
If You're Concerned About a Family Member
If someone in your family is showing symptoms that might suggest Lewy body dementia — fluctuating clarity of thought, detailed visual hallucinations, significant changes in sleep behavior, new movement problems alongside cognitive changes — the most important step is a thorough evaluation by a neurologist. A primary care physician is a reasonable starting point, but given how commonly Lewy body dementia is misdiagnosed in general practice, a specialist referral is worth pursuing.
Be specific with the doctor about all the symptoms you have observed, including the sleep behaviors, which may not come up in a standard cognitive evaluation. A bed partner's account of nighttime behavior is often diagnostically important.
The Lewy Body Dementia Association (lbda.org) is the primary patient advocacy and family support organization in the United States for this condition. They offer a helpline, educational resources, a specialist locator, and support groups — and are a considerably better starting point for family information than a general internet search.