Symptoms of Lewy Body Dementia

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Cognitive: The cognitive symptoms of people with LBD may fluctuate frequently (moment-to-moment, hour-to-hour, or day-to-day). Individuals will be alert (and seem "normal"), and then suddenly become extremely confused, unable to pay attention, or unable to make decisions. Episodes of cognitive impairment may last hours or days.

In addition to problems with attention and reasoning, people with LBD often have impaired visuospatial skills (e.g., impaired depth perception or the ability to see the world in three dimensions; impaired object orientation or understanding how objects appear in space; impaired ability to navigate about the world; and/or illusions, such as mistaking a coat rack for a person).


People with LBD eventually develop impaired memory, but this type of problem does not usually occur until they have had the disease for a period of time. In other words, unlike Alzheimer's Disease, memory symptoms are not the first problem that people with Lewy Body Dementia (or family members) notice.

Movement: People with Lewy Body Dementia "look" somewhat different from people with Alzheimer's Disease and Vascular Dementia, primarily because they have Parkinson's-like symptoms. Parkinson's Disease is a slowly progressive neurological condition that affects the brain and spinal cord, creating symptoms such as tremors (shaking) and rigidity (stiffness). Parkinsonian symptoms in LBD include slow movements, a stooped posture, stiffness in the arms or legs, tremors, a shuffling walking pattern, a mask-like appearance and/or a blank stare, and frequent falls.

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Other symptoms: Other characteristic symptoms that are often disturbing for both affected individuals and their family members set Lewy Body Dementia apart from other types of dementia:

  • Recurrent, vivid visual hallucinations (seeing things that are not really there, such as an attacker in the bedroom) that are extremely difficult to separate from reality. Hallucinations occur most often when people are most confused and can also include sounds, tastes, and smells that aren't truly present.
  • Fluctuating alertness periods (extreme drowsiness followed by sudden bursts of energy) that make it difficult for family members to predict or assess how their relative is doing. People with LBD may also faint repeatedly and without warning.
  • Severe sleep problems (called REM Sleep Behavior Disorder or RBD). During REM sleep (the stage of deep sleep characterized by rapid eye movements), people with LBD will move, gesture, and/or speak. They often seem to be acting out their dreams, and may accidentally hit a spouse or fall out of bed. In addition, some people become extremely confused when they first wake up (and not know the difference between a dream and reality). REM Sleep Behavior Disorder can occur years before people start to show signs of dementia and impaired motor movements. As mentioned above, RBD may be a significant risk factor for developing Lewy Body Dementia.
  • Severe sensitivity to neuroleptics (also called antipsychotic drugs, these medications are often used to treat psychotic disorders like schizophrenia) occurs in up to 50% of individuals with LBD. These medications can worsen cognitive and movement symptoms and/or increase hallucinations. People with LBD can also develop Neuroleptic Malignant Syndrome, which is a life-threatening illness characterized by muscle rigidity, high fever, problems with the autonomic system (see below), and severe confusion and fluctuating alertness.
  • The autonomic nervous system keeps our bodies in balance, or homeostasis, by controlling functions such as heart rate, digestion, breathing rate, perspiration, pupil dilations, the discharge of urine, and sexual arousal. Individuals with LBD often have autonomic system dysfunction, which can lead to blood pressure fluctuations, heart rate variability, sexual dysfunction (e.g., impotence), constipation/urinary problems, excessive or decreased sweating, dry eyes/mouth, and difficulty swallowing.
  • Other psychiatric issues such as delusions (false, fixed beliefs), aggression, and/or depression are not uncommon in individuals with LBD. Aggressive behavior can be triggered by infections (e.g., urinary tract infections), medications, or misinterpretation of the environment or interpersonal interactions due to confusion and/or hallucinations.

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