Common Symptoms

People with 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.

Cognitive Symptoms

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 visual and spatial abilities (judging distance and depth or misidentifying objects), planning, multitasking, problem solving, and reasoning. 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 but are not always easy for a doctor to identify.
  • Hallucinations – Seeing or hearing things that are not present. Visual hallucinations 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. Auditory hallucinations 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.

Movement Symptoms

Some people with LBD may not experience significant movement problems for several years. Others may have them early on. At first, signs of movement problems, such as a change in handwriting, may be very mild and thus 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 gait, slow movement, or frozen stance
  • tremor or shaking, most commonly at rest
  • balance problems and falls
  • stooped posture
  • loss of coordination
  • smaller handwriting than was usual for the person
  • reduced facial expression
  • difficulty swallowing
  • a weak voice

Sleep Disorders

Sleep disorders are common in people with LBD but are often undiagnosed. A sleep specialist can play an important role on a treatment team, helping to diagnose and treat sleep disorders. Sleep-related disorders seen in people with LBD may include:

  • REM sleep behavior disorder – 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. Sometimes only the bed partner of the person with LBD is aware of these symptoms. REM sleep behavior disorder appears in some people 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.

Behavioral and Mood Symptoms

Changes in behavior and mood are possible in LBD. These changes may include:

  • Depression – A persistent feeling of sadness, inability to enjoy activities, or trouble with sleeping, eating, and other normal activities.
  • 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. Another delusion that may be seen in people with LBD is Capgras syndrome, in which the person believes a relative or friend has been replaced by an imposter.
  • Paranoia – An extreme, irrational distrust of others, such as suspicion that people are taking or hiding things.

Other LBD Symptoms

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
  • dizziness
  • fainting
  • frequent falls
  • sensitivity to heat and cold
  • sexual dysfunction
  • urinary incontinence
  • constipation
  • a poor sense of smell

Main Symptoms of Lewy Body Dementia

Symptom Dementia with Lewy Bodies Parkinson’s Disease Dementia
Dementia Appears within a year of movement problems
(Primary symptom)
Appears later in the disease, after movement problems
(Primary symptom)
Movement problems (parkinsonism) Appear at the same time as or after dementia
(Primary symptom)
Appear before dementia
(Primary symptom)
Fluctuating cognition, attention, alertness (Primary symptom) (Primary symptom)
Visual hallucinations (Primary symptom) (Primary symptom)
REM sleep behavior disorder May develop years before other symptoms
(Common symptom)
May develop years before other symptoms
(Common symptom)
Extreme sensitivity to antipsychotic medications (Common symptom) (Common symptom)
Changes in personality and mood (depression, delusions, apathy) (Common symptom) (Common symptom)
Changes in autonomic (involuntary) nervous system (blood pressure, bladder and bowel control) (Common symptom) (Common symptom)

Source: Adapted from the Lewy Body Dementia Association, DLB and PDD Diagnostic Criteria,