title: Nonmotor symptoms in subjects without evidence of dopaminergic deficits.
abstract: BACKGROUND
  A subgroup of patients initially diagnosed with Parkinson's disease (PD) turn out to have normal dopamine transporter single-photon emission computed tomography imaging and have been labeled as subjects without evidence of dopaminergic deficit (SWEDDs). In this study, we sought to further characterize these patients and have analyzed the frequency of nonmotor symptoms (NMS) in SWEDDs, PD patients, and healthy controls.
  
  
  METHODS
  We analyzed the baseline clinical data of 412 PD patients, 184 controls, and 62 SWEDDs included in the Parkinson's Progression Marker Initiative study on a variety of different NMS questionnaires.
  
  
  RESULTS
  Both PD patients and SWEDDs had greater frequency of NMS than healthy controls. Furthermore, some NMS, such as orthostatic hypotension as well as cardiovascular and thermoregulatory dysfunction were even more commonly reported in SWEDDs than in PD patients, whereas hyposmia was more common in PD, compared to SWEDDs.
  
  
  CONCLUSIONS
  NMS are more frequent in SWEDDs than in controls, and autonomic dysfunction and orthostatic hypotension were even more common than in PD patients. These findings support the notion that SWEDDS represent a group of patients with still poorly understood pathophysiology. © 2015 International Parkinson and Movement Disorder Society.
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Fabienne S
authors.initials: FS
authors.lastname: Sprenger
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Seppi
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Atbin
authors.initials: A
authors.lastname: Djamshidian
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Eva
authors.initials: E
authors.lastname: Reiter
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Nocker
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Katherina
authors.initials: K
authors.lastname: Mair
authors.affiliation: Department of Medical Statistics, Informatics and Health Economics, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Göbel
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Poewe
mesh_terms: D000368:Aged; D001833:Body Temperature Regulation / Q000502:physiology; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000145:classification / Q000503:physiopathology*
keywords: Parkinson's disease; SWEDDs; nonmotor symptoms