Last reviewed: 8 Apr 2021
Last updated: 24 Aug 2018



History and exam

Key diagnostic factors

  • cognitive fluctuations
  • visual hallucinations
  • motor symptoms
  • rapid eye movement (REM) sleep behavioral disturbance

Other diagnostic factors

  • severe antipsychotic sensitivity
  • depression
  • repeated falls and syncope
  • orthostatic hypotension
  • urinary incontinence
  • constipation
  • attention and visuospatial abnormalities
  • delusions
  • hypersomnia
  • hyposmia
  • auditory hallucinations

Risk factors

  • older age
  • male gender
  • familial occurrence

Diagnostic investigations

1st investigations to order

  • CBC
  • metabolic panel
  • serum thyroid-stimulating hormone (TSH)
  • serum vitamin B12
  • serum folate
  • serum VDRL
  • urine drug screen
  • urinalysis
  • HIV testing

Investigations to consider

  • CT brain
  • MRI brain
  • quantitative EEG
  • cerebrospinal fluid (CSF) analysis
  • neuropsychological testing
  • single-photon emission CT (SPECT)/positron emission tomography (PET)
  • MIBG myocardial scintigraphy

Treatment algorithm


Professor of Neurology

Department of Neurology

University Hospitals Case Medical Center

Case Western Reserve University




AJL receives research grant support from NIH, TauRx, Eli Lilly, and Axovant, and has been a medicolegal consultant in several legal cases, but he declares that he has no competing interests related to this topic.

Dr Alan J. Lerner would like to gratefully acknowledge Dr Brian S. Appleby, Dr Ethan Gore, Dr Rajeet Shrestha, Dr Timothy Wuerz, Dr Julie Schneider, Dr Viola Fahmy, and Dr Sube Banerjee, previous contributors to this topic. BSA, EG, RS, TW, JS, VF, and SB declare that they have no competing interests.

Peer reviewersVIEW ALL

Assistant Professor and Clinical Neuropsychologist

Department of Neurological Sciences

Rush University Medical Center




BB declares that he has no competing interests.

Associate Professor

Neurology, Psychiatry and Neurobiology


Memory Diagnostic Center and Alzheimer Treatment Unit


Education and Community Outreach

Alzheimer Disease Research Center

Washington University School of Medicine

St Louis



JEG declares that he has no competing interests.

Professor of Old Age Psychiatry

Clinical Director

Institute for Ageing and Health

Newcastle University




IM is the author of several references cited in this topic.

Use of this content is subject to our disclaimer