title: Levodopa Responsiveness in Adult-onset Lower Limb Dystonia is Associated with the Development of Parkinson's Disease.
abstract: BACKGROUND
  Adult-onset primary lower limb dystonia (AOPLLD) has been reported as an early sign of Parkinson's disease (PD) or Parkinson-plus syndrome in case series. No prior systematic analysis has assessed clinical clues predicting later development of PD or Parkinson-plus syndrome.
  
  
  METHODS
  We identified patients with AOPLLD from medical records. We excluded patients who had not been diagnosed by a neurologist, and who had a pre-existing diagnosis of PD, psychogenic, or secondary dystonia. Records were subdivided into those who later developed PD or Parkinson-plus disorders and those who did not. The following clinical characteristics were compared between the two groups: dystonia onset age, type of dystonia, levodopa response, anticholinergic response, and family history of Parkinsonism or tremor.
  
  
  RESULTS
  Twenty-two AOPLLD patients were identified: 77% female; the median dystonia onset age was 53 years. Eight (37%) developed Parkinson's disease; 2 (9%) developed corticobasal syndrome. Twelve patients (54%) did not develop Parkinsonism after a median follow-up period of 1.5 years. There was a significant difference in leg dystonia levodopa response between the two groups (p = 0.02).
  
  
  CONCLUSIONS
  In patients with AOPLLD, leg dystonia with levodopa response is associated with the future development of PD.
authors.affiliation: Mayo Clinic, Rochester, Minnesota, United States of America.
authors.forename: Florence C F
authors.initials: FC
authors.lastname: Chang
authors.forename: Keith A
authors.initials: KA
authors.lastname: Josephs
keywords: Dystonia; Parkinson’s disease; leg dystonia; levodopa