title: The concept and diagnostic criteria of primary lateral sclerosis.
abstract: OBJECTIVE
  Primary lateral sclerosis (PLS) is commonly considered as a motor neuron disease (MND) variant which almost exclusively affects upper motor neurons (UMN). There is still no consensus whether PLS should be regarded as an independent disease entity separate from amyotrophic lateral sclerosis (ALS) or as a comparatively slowly progressive variant of ALS. Given these different views, clinical diagnosis of PLS is a challenge. In this multicenter study, we analyzed clinical features of patients diagnosed with PLS in four specialized MND centers.
  
  
  METHODS
  We retrospectively analyzed clinical, laboratory, imaging, and electrophysiological data of 76 patients with PLS diagnosed in four specialized ALS centers. We analyzed the concept of the disease based on our findings and an extensive review of the literature.
  
  
  RESULTS
  We found that 79% of patients showed asymmetrical symptoms, 60% showed clinical or electrophysiological signs of lower motor neuron (LMN) involvement after a mean of 8.4 ± 5.0 years, and extrapyramidal and/or non-motoric symptoms were frequently observed. Interestingly, none of the patients diagnosed with PLS fulfilled the diagnostic criteria proposed by Pringle et al. in 1992.
  
  
  CONCLUSIONS
  Our data show that PLS as a disease entity is still not well enough defined and that there are different concepts about its clinical presentation. We believe that further prospective longitudinal studies are needed in order to refine diagnostic criteria to reflect current clinical practice. Furthermore, neuropathological and neuroimaging approaches might help to arrange PLS in the MND spectrum and its classification.
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Wais
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Rosenbohm
authors.affiliation: Department of Neurology, University of Hannover, Hannover, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Petri
authors.affiliation: Department of Neurology, University of Hannover, Hannover, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Kollewe
authors.affiliation: Department of Neurology, Division for Neurodegenerative Diseases, Dresden University of Technology, Dresden, Germany.|German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hermann
authors.affiliation: Department of Neurology, Division for Neurodegenerative Diseases, Dresden University of Technology, Dresden, Germany.|German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.|Department of Neurology, University Medical Center Rostock, Rostock, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Storch
authors.affiliation: Department of Neurology, Evangelisches Krankenhaus Königin Elisabeth Herzberge, Berlin, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Hanisch
authors.affiliation: Department of Neurology, University of Halle, Halle, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Zierz
authors.affiliation: Institute for Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Nagel
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Kassubek
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Weydt
authors.affiliation: CaritasKlinikum, Saarbrücken, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Brettschneider
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Jochen H
authors.initials: JH
authors.lastname: Weishaupt
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Albert C
authors.initials: AC
authors.lastname: Ludolph
authors.affiliation: Department of Neurology, University of Ulm, Ulm, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Dorst
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology
keywords: amyotrophic lateral sclerosis; diagnostic criteria; motor neuron disease; multi-system degeneration; primary lateral sclerosis; pringle criteria