title: All in the blink of an eye: new insight into cerebellar and brainstem function in DYT1 and DYT6 dystonia.
abstract: OBJECTIVE
  Traditionally dystonia has been considered a disorder of basal ganglia dysfunction. However, recent research has advocated a more complex neuroanatomical network. In particular, there is increasing interest in the pathophysiological role of the cerebellum. Patients with cervical and focal hand dystonia have impaired cerebellar associative learning using the paradigm eyeblink conditioning. This is perhaps the most direct evidence to date that the cerebellum is implicated in patients.
  
  
  METHODS
  Eleven patients with DYT1 dystonia and five patients with DYT6 dystonia were examined and rates of eyeblink conditioning were compared with age-matched controls. A marker of brainstem excitability, the blink reflex recovery, was also studied in the same groups.
  
  
  RESULTS
  Patients with DYT1 and DYT6 dystonia have a normal ability to acquire conditioned responses. Blink reflex recovery was enhanced in DYT1 but this effect was not seen in DYT6.
  
  
  CONCLUSIONS
  If the cerebellum is an important driver in DYT1 and DYT6 dystonia our data suggest that there is specific cerebellar dysfunction such that the circuits essential for conditioning function normally. Our data are contrary to observations in focal dystonia and suggest that the cerebellum may have a distinct role in different subsets of dystonia. Evidence of enhanced blink reflex recovery in all patients with dystonia was not found and recent studies calling for the blink recovery reflex to be used as a diagnostic test for dystonic tremor may require further corroboration.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Sadnicka
authors.forename: J T
authors.initials: JT
authors.lastname: Teo
authors.forename: M
authors.initials: M
authors.lastname: Kojovic
authors.forename: I
authors.initials: I
authors.lastname: Pareés
authors.forename: T A
authors.initials: TA
authors.lastname: Saifee
authors.forename: P
authors.initials: P
authors.lastname: Kassavetis
authors.forename: P
authors.initials: P
authors.lastname: Schwingenschuh
authors.forename: P
authors.initials: P
authors.lastname: Katschnig-Winter
authors.forename: M
authors.initials: M
authors.lastname: Stamelou
authors.forename: N E
authors.initials: NE
authors.lastname: Mencacci
authors.forename: J C
authors.initials: JC
authors.lastname: Rothwell
authors.forename: M J
authors.initials: MJ
authors.lastname: Edwards
authors.forename: K P
authors.initials: KP
authors.lastname: Bhatia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001767:Blinking / Q000502:physiology*; D001933:Brain Stem / Q000503:physiopathology; D002526:Cerebellar Diseases / Q000503:physiopathology*; D003213:Conditioning, Psychological / Q000502:physiology*; D004422:Dystonia Musculorum Deformans / Q000503:physiopathology*; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: DYT1; DYT6; cerebellum; dystonia; neurophysiology