What are Lewy body dementia signs and symptoms?

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People with Lewy body dementia may not have every symptom associated with the disease. Any sudden or major change in functional ability or behavior should be reported to a doctor.

The most common symptoms include changes in cognition, movement, sleep, and behavior.

Cognitive symptoms of Lewy body dementia

LBD causes changes in thinking abilities. These changes may include:

Visual hallucinations, or seeing things that are not present. Visual hallucinations occur in up to 80 percent of people with LBD, often early on.

Nonvisual hallucinations, such as hearing or smelling things that are not present, are less common than visual ones but may also occur.

Unpredictable changes in concentration, attention, alertness, and wakefulness from day to day and sometimes throughout the day.

Ideas may be disorganized, unclear, or illogical. These kinds of changes are common in LBD and may help distinguish it from Alzheimer’s disease.

Severe loss of thinking abilities that interfere with daily activities. Unlike in Alzheimer’s dementia, memory problems may not be evident at first but often arise as LBD progresses.

Other changes related to thinking may include poor judgment, confusion about time and place, and difficulty with language and numbers.

Movement problems and Lewy body dementia

Some people with LBD may not experience significant movement problems for several years. Others may have them early on.

At first, movement symptoms, such as a change in handwriting, may be very mild and easily overlooked. Movement problems may include:

Muscle rigidity or stiffness

Shuffling walk, slow movement, or frozen stance

Tremor or shaking, most commonly at rest

Balance problems and repeated falls

Stooped posture

Loss of coordination

Smaller handwriting than was usual for the person

Reduced facial expression

Difficulty swallowing

A weak voice

Lewy body dementia and sleep

Sleep disorders are common in people with LBD, but are often undiagnosed. A sleep specialist can help diagnose and treat sleep disorders. Sleep-related disorders seen in people with LBD may include:

REM sleep behavior disorder

Excessive daytime sleepiness (sleeping two or more hours during the day)


Restless leg syndrome

Behavioral and mood symptoms of Lewy body dementia

Changes in behavior and mood are possible in LBD and may worsen as the person’s thinking abilities decline. These changes may include:


Apathy, or a lack of interest in normal daily activities or events and less social interaction

Anxiety and related behaviors, such as asking the same questions over and over or being angry or fearful when a loved one is not present

Agitation, or restlessness, and related behaviors, such as pacing, hand wringing, an inability to get settled, constant repeating of words or phrases, or irritability

Delusions, or strongly held false beliefs or opinions not based on evidence. For example, a person may think his or her spouse is having an affair or that relatives long dead are still living.

Paranoia, or an extreme, irrational distrust of others, such as suspicion that people are taking or hiding things

Other symptoms of Lewy body dementia

People with LBD can also experience significant changes in the part of the nervous system that regulates automatic functions such as those of the heart, glands, and muscles. The person may have:

Changes in body temperature

Problems with blood pressure



Frequent falls

Sensitivity to heat and cold

Sexual dysfunction

Urinary incontinence


A poor sense of smell

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