Symptoms of Lewy Body Dementia
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People with Lewy body dementia (LBD) may not have every LBD symptom, and the severity of symptoms can vary greatly from person to person. Throughout the course of 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.
LBD causes changes in thinking abilities. These changes may include:
- Dementia—Severe loss of thinking abilities that interferes with a person's capacity to perform daily activities. Dementia is a primary symptom in LBD and usually includes trouble with attention, visual and spatial abilities (judging distance and depth or misidentifying objects), planning, multitasking, problem solving, and reasoning. Unlike in Alzheimer's dementia, memory problems may not be evident at first but often arise as LBD progresses. Dementia can also include changes in mood and behavior, poor judgment, loss of initiative, confusion about time and place, and difficulty with language and numbers.
- Cognitive fluctuations—Unpredictable changes in concentration, attention, alertness, and wakefulness from day to day and sometimes throughout the day. A person with LBD may stare into space for periods of time, seem drowsy and lethargic, or sleep for several hours during the day despite getting enough sleep the night before. His or her flow of ideas may be disorganized, unclear, or illogical at times. The person may seem better one day, then worse the next day. These cognitive fluctuations are common in LBD and may help distinguish it from Alzheimer's disease.
- Hallucinations—Visual hallucinations—seeing things that are not present—occur in up to 80 percent of people with LBD, often early on. They are typically realistic and detailed, such as images of children or animals. Nonvisual hallucinations, such as hearing or smelling things that are not present, are less common than visual ones but may also occur. Hallucinations that are not disruptive may not require treatment. However, if they are frightening or dangerous (for example, if the person attempts to fight a perceived intruder), then a doctor may prescribe medication.
Main Characteristics of Lewy Body Dementia
Core Clinical Symptoms
- Movement problems/parkinsonism
- Cognitive fluctuations
- Visual hallucinations
- REM sleep behavior disorder
Supportive Clinical Symptoms
- Extreme sensitivity to antipsychotic medications
- Falls, fainting
- Severe problems with involuntary functions (maintaining blood pressure, incontinence, constipation, loss of smell)
- Changes in personality and mood (depression, apathy, anxiety)
Test Results Supporting Diagnosis
- PET or SPECT brain scan showing reduced dopamine transporter (DaT) uptake in basal ganglia (brain region)
- Abnormal 123iodine-MIBG myocardial scintigraphy showing reduced communication of cardiac nerves
- Sleep study confirming REM sleep behavior disorder without loss of muscle tone
For more information visit the Lewy Body Dementia Association's Comprehensive LBD Symptoms Checklist.
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. Parkinsonism is seen early on in Parkinson's disease dementia but can also develop later on in dementia with Lewy bodies. Specific signs of parkinsonism 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
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 (RBD)—A condition in which a person seems to act out dreams. It may include vivid dreaming, talking in one's sleep, violent movements, or falling out of bed. RBD may be the earliest symptom of LBD in some people, appearing many years before other LBD symptoms.
- Excessive daytime sleepiness—Sleeping 2 or more hours during the day.
- Insomnia—Difficulty falling or staying asleep, or waking up too early.
- Restless leg syndrome—A condition in which a person, while resting, feels the urge to move his or her legs to stop unpleasant or unusual sensations. Walking or moving usually relieves the discomfort.
Changes in behavior and mood are possible in LBD and may worsen as cognition declines. These changes may include:
- Depression—A persistent feeling of sadness, worthlessness, or inability to enjoy activities, often with trouble with sleeping or eating.
- Apathy—A lack of interest in normal daily activities or events; less social interaction.
- Anxiety—Intense apprehension, uncertainty, or fear about a future event or situation. A person may ask the same questions over and over or be angry or fearful when a loved one is not present.
- Agitation—Restlessness, as seen by pacing, hand wringing, an inability to get settled, constant repeating of words or phrases, or irritability.
- Delusions—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. Capgras syndrome, in which the person believes a relative or friend has been replaced by an imposter, may also appear.
- Paranoia—An extreme, irrational distrust of others, such as suspicion that people are taking or hiding things.
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
For More Information About Symptoms of LBD
NIA Alzheimer’s and related Dementias Education and Referral (ADEAR) Center
The National Institute on Aging’s ADEAR Center offers information and free print publications about Alzheimer’s disease and related dementias for families, caregivers, and health professionals. ADEAR Center staff answer telephone, email, and written requests and make referrals to local and national resources.
Lewy Body Dementia Association
1-844-311-0587 (toll-free LBD Caregiver Link)
National Library of Medicine
Content reviewed: June 27, 2018