title: The Differential Diagnosis and Treatment of Atypical Parkinsonism.
abstract: BACKGROUND
  Aside from idiopathic Parkinson syndrome (Parkinson's disease), there are a number of other, so-called atypical parkinsonian syndromes: dementia with Lewy bodies (DLB), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD). DLB is a common disease, with a prevalence of 0.4% (400 cases per 100 000 persons) in the elderly; MSA and PSP both have a prevalence of 5 to 10 per 100 000 persons, while the prevalence of CBD is about 1 per 100 000.
  
  
  METHODS
  This review is based on pertinent publications retrieved by a selective literature search.
  
  
  RESULTS
  The atypical parkinsonian syndromes are synucleinopathies and tauopathies, i.e., disorders characterized by the abnormal deposition of the proteins α-synuclein and tau. The site of deposition is correlated with the clinical features. In DLB, synuclein is mainly deposited in neocortical neurons, with some brain stem involvement as well. The main clinical features are dementia and, later on, parkinsonism. In MSA, synuclein is deposited in oligodendrocytes, mainly in the cerebellum but also in the brain stem; the main clinical feature is autonomic dysfunction combined with parkinsonism or cerebellar ataxia. Synucleinopathies often impair REM (rapid eye movement) sleep. PSP and CBD, on the other hand, are primary tauopathies. PSP usually causes predominantly supranuclear vertical gaze palsy and early postural instability with falls, less commonly parkinsonism (PSP-P) or frontotemporal dementia (PSP-FTD) as its most prominent feature. CBD typically manifests itself as markedly asymmetrical parkinsonism with apraxia or cortical sensory disturbance. At present, there is no accepted causal treatment for any of these disorders; the available symptomatic treatments are of limited efficacy and are supported only by low-level evidence.
  
  
  CONCLUSIONS
  Causal treatments for neurodegenerative diseases are now being developed and tested, and thus a molecular diagnosis is desirable. This will require the cooperation of primary care physicians with specialized centers.
authors.affiliation: Department of Neurology, Klinikum rechts der Isar, Technische Universität München and Chair for Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), Munich, Department of Neurology, Ludwig-Maximilians-Universität München, German Center for Neurodegenerative Diseases (DZNE), Munich, Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technische Universität München, Center for Neuropathology and Prion Research (ZNP), Ludwig-Maximilians-Universität München, Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-Universität München.
authors.forename: Johannes
authors.initials: J
authors.lastname: Levin
authors.forename: Alexander
authors.initials: A
authors.lastname: Kurz
authors.forename: Thomas
authors.initials: T
authors.lastname: Arzberger
authors.forename: Armin
authors.initials: A
authors.lastname: Giese
authors.forename: Günter U
authors.initials: GU
authors.lastname: Höglinger
mesh_terms: D003937:Diagnosis, Differential; D019317:Evidence-Based Medicine; D006801:Humans; D010300:Parkinson Disease / Q000175:diagnosis* / Q000628:therapy*; D020734:Parkinsonian Disorders / Q000175:diagnosis* / Q000628:therapy*; D016896:Treatment Outcome