title: Movement preparation and cortical processing of afferent inputs in cortical tremor: an event-related (de)synchronization (ERD/ERS) study.
abstract: OBJECTIVE
  We sought to characterize cortical activity related to motor control in patients presenting with isolated cortical tremor, in order to determine whether or not myoclonus-related impairments are a source of event-related desynchronization/synchronization (ERD/ERS) disruption.
  
  
  METHODS
  Nine patients presenting with isolated cortical tremor were compared with controls. Mu and beta ERD/ERS were computed over the scalp and brain surfaces using 128-channel electroencephalographic (EEG) recording during voluntary and passive finger extensions. We recorded somatosensory-evoked potentials following median nerve stimulation and performed myoclonic jerk-locked back-averaging of EEG activity.
  
  
  RESULTS
  Back-averaging revealed a cortical premyoclonic spike in all patients. Five of the nine patients had exaggerated SEPs. The amplitude of mu ERD was greater in patients. Beta ERD/ERS did not differ from that seen in controls. Localizations of mu and beta ERD/ERS did not differ from controls and were identified in pre- and post-central sensorimotor cortical areas.
  
  
  CONCLUSIONS
  The present results suggest a hyperexcitability of the cortico-subcortical loops responsible for movement preparation and execution. Post-movement inhibition related to cortical processing of afferent input is unaffected in isolated cortical myoclonus.
  
  
  CONCLUSIONS
  Intracortical abnormalities can differ in patients suffering from cortical myoclonus, according to whether or not the individuals have associated epileptic symptoms.
authors.affiliation: Departement de Neurophysiologie Clinique, Hôpital Roger Salengro, EA 2683, Centre Hospitalier Régional Universitaire, F-59037 Lille cedex, France.
authors.forename: E
authors.initials: E
authors.lastname: Houdayer
authors.forename: A
authors.initials: A
authors.lastname: Degardin
authors.forename: J
authors.initials: J
authors.lastname: Salleron
authors.forename: J L
authors.initials: JL
authors.lastname: Bourriez
authors.forename: L
authors.initials: L
authors.lastname: Defebvre
authors.forename: F
authors.initials: F
authors.lastname: Cassim
authors.forename: P
authors.initials: P
authors.lastname: Derambure
mesh_terms: D000328:Adult; D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology*; D003344:Cortical Synchronization / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D009475:Neurons, Afferent / Q000502:physiology*; D014202:Tremor / Q000503:physiopathology*