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Lewy Body Dementia Symptoms and Diagnostic Criteria

Every person with LBD is different and will manifest different degrees of the following symptoms. Some will show no signs of certain features, especially in the early stages of the disease. Symptoms may fluctuate as often as moment-to-moment, hour-to-hour or day-to-day.

LBD is a an umbrella term for two related clinical diagnoses, dementia with Lewy bodies and Parkinson’s disease dementia.

The latest clinical diagnostic criteria for dementia with Lewy bodies (DLB) categorizes symptoms into three types, listed below. A diagnosis of Parkinsons’ disease dementia (PDD) requires a well established diagnosis of Parkinson’s disease that later progresses into dementia, along with very similar features to DLB. A rather arbitrary time cutoff was established to differentiate between DLB and PDD. People whose dementia occurs before or within 1 year of Parkinson’s symptoms are diagnosed with DLB. People who have an existing diagnosis of Parkinson’s for more than a year and later develop dementia are diagnosed with PDD.

Central feature

  • Progressive dementia – deficits in attention and executive function are typical. Prominent memory impairment may not be evident in the early stages.

Core features

  • Fluctuating cognition with pronounced variations in attention and alertness.
  • Recurrent complex visual hallucinations, typically well formed and detailed.
  • Spontaneous features of Parkinsonism.

Suggestive features

  • REM sleep behavior disorder (RBD), which can appear years before the onset of dementia and Parkinsonism.
  • Severe sensitivity to neuroleptics occurs in up to 50% of LBD patients who take them.
  • Low dopamine transporter uptake in the brain’s basal ganglia as seen on SPECT and PET imaging scans.

Supportive features

  • Repeated falls and syncope (fainting).
  • Transient, unexplained loss of consciousness.
  • Autonomic dysfunction.
  • Hallucinations of other senses, like touch or hearing.
  • Visuospatial abnormalities.
  • Other psychiatric disturbances.

A clinical diagnosis of LBD can be probable or possible based on different symptom combinations.

A probable LBD diagnosis requires either:

  • Dementia plus two or more core features, or
  • Dementia plus one core feature and one or more suggestive features.

A possible LBD diagnosis requires:

  • Dementia plus one core feature, or
  • Dementia plus one or more suggestive features.

Content courtesy of LBDA. The Lewy Body Dementia Association (LBDA) is a 501(c)(3) nonprofit organization dedicated to raising awareness of the Lewy body dementias (LBD), supporting people with LBD, their families and caregivers and promoting scientific advances.