title: A distinctive pattern of cortical excitability in patients with the syndrome of dystonia and cerebellar ataxia.
abstract: OBJECTIVE
  The syndrome of dystonia and cerebellar ataxia (DYTCA) is a recently described condition where cervical dystonia and mild cerebellar ataxia are the major clinical features. Here we attempted to explore the pathophysiology of this condition by comparing measurements of cortical excitability between patients with DYTCA, typical primary dystonia and healthy controls.
  
  
  METHODS
  Motor threshold, active MEP recruitment and CSP duration were measured and the excitability of the intracortical inhibitory and excitatory circuits was assessed at rest using a paired pulse protocol.
  
  
  RESULTS
  We identified a distinctive pattern of cortical excitability in DYTCA patients different from that found in primary dystonia, namely hyperexcitable short-interval intracortical inhibition.
  
  
  CONCLUSIONS
  DYTCA patients have a noticeably dissimilar excitability profile from patients with primary dystonia.
  
  
  CONCLUSIONS
  A tendency for increased SICI has been previously described in cerebellar syndromes and the altered excitability profile seen in these patients is therefore possibly a consequence of the cerebellar dysfunction in DYTCA. A direct link between reduced intracortical inhibition and dystonia has recently been questioned and our results additionally suggest that reduced motor cortex inhibition is not a prerequisite for dystonia to occur.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, UCL, London WC1N 3BG, UK.
authors.forename: Penelope
authors.initials: P
authors.lastname: Talelli
authors.forename: Britt S
authors.initials: BS
authors.lastname: Hoffland
authors.forename: Susanne A
authors.initials: SA
authors.lastname: Schneider
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Edwards
authors.forename: Kailash P
authors.initials: KP
authors.lastname: Bhatia
authors.forename: Bart P C
authors.initials: BP
authors.lastname: van de Warrenburg
authors.forename: John C
authors.initials: JC
authors.lastname: Rothwell
mesh_terms: D000328:Adult; D002524:Cerebellar Ataxia / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D020821:Dystonic Disorders / Q000503:physiopathology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013577:Syndrome; D050781:Transcranial Magnetic Stimulation