title: Impairment of neuromuscular transmission in transient global amnesia - does it really exist?
abstract: BACKGROUND
  The main hypotheses regarding mechanisms of transient global amnesia (TGA) are ischemia in hippocampal structures, epileptic genesis, and migraine. In accordance with the hypothesis of a shared, common pathophysiological mechanism in both TGA and migraine, neuromuscular transmission (NMT) abnormalities previously found in migraine were also suspected in TGA.
  
  
  OBJECTIVE
  The aim of our study was to analyze NMT in TGA patients to reveal a subclinical impairment of neuromuscular transmission as a possible indicator of underlying channelopathy, which would point to a shared etiology with migraine.
  
  
  METHODS
  The study group consisted of 15 patients (6 males) with TGA (mean age 69.5±7.4yrs). The duration of amnesia ranged from 1 to 6h (mean 4.4h). Single fiber electromyography (SFEMG), the most sensitive tool for NMT assessment, of the voluntarily activated frontal muscle was performed 1-5 days after a TGA incident.
  
  
  RESULTS
  Abnormal SFEMG was found in 1 patient (6.6%). In all other patients, SFEMG was in the normal range.
  
  
  CONCLUSIONS
  Our neurophysiological study does not confirm NMT defects in TGA. The role of channelopathy with NMT dysfunction in the pathogenesis of TGA is rather unlikely, whereas subclinical NMT abnormalities were certainly proven in migraine.
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland. Electronic address: mgawel@wum.edu.pl.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Gaweł
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Domitrz
authors.affiliation: Faculty of Mathematics and Information Science, Warsaw University of Technology, Warsaw, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Domitrz
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Szmidt-Sałkowska
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kamińska
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020236:Amnesia, Transient Global / Q000150:complications*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009468:Neuromuscular Diseases / Q000209:etiology* / Q000473:pathology*; D009469:Neuromuscular Junction / Q000503:physiopathology*; D013997:Time Factors
keywords: Frontal muscle; Jitter; Migraine; Neuromuscular transmission; Single fiber electromyography; Transient global amnesia