Lewy Body Dementia: Signs and Symptoms

Dementia is a broad term that describes the loss of cognitive abilities like thinking, remembering, using language, and making decisions. Lewy body dementia (LBD) is one type of dementia, named after the scientist who discovered this variation. This type of dementia is thought to be caused by a buildup of a specific protein in the brain.  

There are two types of LBD: dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD). In general, both types of LBD are caused by the same accumulation of protein in the brain and have the same symptoms, including loss of cognitive abilities, changes in sleep and behavior, hallucinations, and movement or coordination challenges. Both types of LBD are also progressive, meaning most people will have mild symptoms at first that steadily worsen over time. 

The main difference between DLB and PDD is the order in which symptoms appear. In DLB, cognitive changes happen first, followed by movement symptoms. In PDD, people experience movement-related difficulties and are typically diagnosed with Parkinson’s disease, only to then experience dementia symptoms later on.

The cognitive (brain-related) changes of Lewy body dementia include many different types of symptoms, from loss of memory to hallucinations to changes in alertness. Because LBD is progressive, people typically have only a few or mild symptoms at first, with more frequent and severe symptoms developing over the course of the disease.

These symptoms are most common:

• Difficulty paying attention
• Trouble organizing thoughts
• Challenges with making decisions and problem-solving
• Inability to stay awake during the day
• Visual hallucinations (seeing or smelling things that aren’t there)
• Forgetting how to speak
• Not being able to remember details or recall memories

People with LBD most often experience changes to their cognition and movement abilities, though usually not at the same time and not in the same order. People diagnosed with Parkinson’s disease dementia will notice movement changes first before developing cognitive changes (and vice versa for people with dementia with Lewy bodies).

Changes in movement can include the following symptoms:

• Shaking or tremors in the hands
• Stiffness or rigidity
• Slowed movement, especially when walking
• Freezing in place
• Posture changes
• Limited facial expressions
• Changes in handwriting
• Loss of balance or increase in falls
• Trouble swallowing

The changes to the brain that happen with Lewy body dementia can cause serious disruptions to sleep. In fact, as many as 90% of people with LBD might be affected by sleep disturbances. This can include:

• Feeling excessively sleepy or sleeping more during the day
• Not being able to sleep well at night
• Having an increased risk of restless legs syndrome (RLS), which causes uncomfortable sensations in your legs and an inability to keep them still at night
• Acting out dreams, talking during sleep, and falling out of bed due to changes in rapid eye movement (REM) sleep

The sleep symptoms of LBD can occur at any time during the disease. Changes in REM sleep can even be considered one of the earliest signs of LBD, beginning long before other symptoms.

Typically occurring as LBD progresses over time, behavior symptoms can be troubling and difficult to manage for both people with the disease and their caregivers. These behavior symptoms may look like:

• Agitation, restlessness, or irritability
• Depression
• Anxiety or fear
• Apathy
• Withdrawal from social situations
• Physical or verbal aggression
• Paranoia or extreme distrust of others
• Loss of inhibitions, such as saying or doing socially inappropriate things
• Delusions

The autonomic nervous system (ANS) is the part of the body responsible for regulating involuntary actions like breathing, heart rate, blood pressure, and digestion. Some people with Lewy body dementia will notice changes to their autonomic nervous system, such as:

• Inability to regulate body temperature or extreme sensitivity to temperature changes
• Dizziness or fainting
• Incontinence (loss of urinary control)
• Constipation
• Problems with sweating
• Erectile dysfunction
• Loss of smell

It can be challenging to tell when symptoms of Lewy body dementia begin since they can mimic symptoms of other cognitive or movement-related disorders or even look like the signs of normal aging at first. That said, while there’s no cure for LBD, treatments can improve the lives of both the person living with dementia and their caregivers.

If you or your loved one has had persistent changes to their cognitive abilities, physical movements, or behaviors, see a healthcare provider for further evaluation. They can help you and your loved one understand what’s causing their symptoms and offer appropriate treatment options.

Lewy body dementia is a common type of dementia caused by a buildup of proteins in the brain. The condition has two types: dementia with Lewy bodies and Parkinson’s disease dementia. Both types cause similar symptoms, such as changes in cognition, movement, sleep, behavior, and nervous system functioning.

If you or a loved one are experiencing symptoms of LBD, seeing a healthcare provider for support and evaluation is important.