title: Reduced intracortical facilitation in patients with cerebellar degeneration.
abstract: OBJECTIVE
  Transcranial magnetic stimulation (TMS) was used to study intracortical inhibitory and excitatory phenomena in patients with cerebellar ataxia.
  
  
  METHODS
  Motor evoked potentials (MEP) following single and paired TMS were recorded from the first dorsal interosseus muscle (FDI) in 15 patients with autosomal-dominant or idiopathic cerebellar ataxia and 15 age matched normal controls.
  
  
  RESULTS
  MEP amplitudes after paired TMS with short interstimulus intervals (1-4 ms) showing intracortical inhibition in the control group were not significantly different in the patient group. In contrast, with longer interstimulus intervals (8-20 ms) mean MEP amplitudes were significantly reduced in the patient group, indicating a decrease of intracortical facilitation. The mean postexcitatory inhibition after TMS was also significantly prolonged in the patient group.
  
  
  CONCLUSIONS
  Our findings support the idea that the cerebellum physiologically exerts a facilitatory influence on the motor cortex which is decreased in patients with a cerebellar degeneration.
authors.affiliation: Department of Neurology, Ruhr-University Bochum, BG-Kliniken Bergmannsheil, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Liepert
authors.forename: K
authors.initials: K
authors.lastname: Wessel
authors.forename: P
authors.initials: P
authors.lastname: Schwenkreis
authors.forename: P
authors.initials: P
authors.lastname: Trillenberg
authors.forename: V
authors.initials: V
authors.lastname: Otto
authors.forename: M
authors.initials: M
authors.lastname: Vorgerd
authors.forename: J P
authors.initials: JP
authors.lastname: Malin
authors.forename: M
authors.initials: M
authors.lastname: Tegenthoff
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D002524:Cerebellar Ataxia / Q000473:pathology*; D004569:Electroencephalography; D004574:Electromagnetic Fields; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology* / Q000502:physiology