title: Previous Injury and Chronic Pain are Associated with Side of Onset in Parkinson's Disease.
abstract: BACKGROUND
  Parkinson's disease (PD) motor symptoms are frequently asymmetric and the factors that influence the side of onset are unclear.
  
  
  OBJECTIVE
  To explore whether peripheral injury and associated chronic limb pain may influence the side of onset.
  
  
  METHODS
  We administered a questionnaire to 128 PD patients in a tertiary movement disorder clinic. Handedness, date and type of limb injury(s) and duration of associated pain, and date and side of onset were ascertained.
  
  
  RESULTS
  Sixty-two subjects reported limb injuries prior to the onset of PD symptoms, 30 with and 32 without chronic pain (i.e., ≥ 2 months). There was no association between injury and PD onset side overall (p=0.334). In subjects with chronic pain associated with limb injuries, however, side of injuries was associated with the side of PD symptom onset (p=0.030).
  
  
  CONCLUSIONS
  Limb injury with chronic pain may be related to the side of PD symptom onset. Future studies may shed light on the nature of this observation.
authors.affiliation: Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Izel
authors.initials: I
authors.lastname: Tekin
authors.affiliation: Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Angeliki
authors.initials: A
authors.lastname: Vgontzas
authors.affiliation: Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Neurology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Mechelle M
authors.initials: MM
authors.lastname: Lewis
authors.affiliation: Department of Neurology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Saira
authors.initials: S
authors.lastname: Kothari
authors.affiliation: Department of Public Health Sciences Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Kong
authors.affiliation: Department of Kinesiology, Statistics8 Pennsylvania State University, University Park, PA, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
authors.forename: Kent E
authors.initials: KE
authors.lastname: Vrana
authors.affiliation: Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Neurology, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Radiology, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Kinesiology, Pennsylvania State University, University Park, PA, USA.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Huang
keywords: Handedness; Parkinson's disease; Peripheral limb injury; Side of onset