title: Edrophonium Challenge Test for Blepharospasm.
abstract: BACKGROUND
  Blepharospasm is typically diagnosed by excluding any secondary diseases and neuropsychiatric disorders, as specific tests for blepharospasm are currently unavailable. Since anticholinergic agents are used to improve the symptoms of dystonia, we hypothesized that edrophonium chloride, an acetylcholinesterase inhibitor, may make the symptoms of dystonia more apparent. Therefore, we examined whether an edrophonium challenge test would be useful for diagnosing blepharospasm.
  
  
  METHODS
  We studied 10 patients with blepharospasm and 10 with hemifacial spasms (as disease controls). We administered edrophonium and saline in this double-blind study. Before and after the injection, we recorded the clinical signs using a video camera to assess the objective symptoms every 2 min. Ten minutes after the isotonic sodium chloride and edrophonium injections, the patients evaluated their subjective signs using a visual analog scale (VAS). The objective signs on the video recordings were scored by specialists who were blind to the treatment.
  
  
  RESULTS
  The subjective and objective signs of the patients with blepharospasm were amplified by edrophonium. In contrast, the signs in patients with hemifacial spasms were not changed by the edrophonium challenge test.
  
  
  CONCLUSIONS
  The edrophonium challenge test may be used to diagnose blepharospasm. The study was registered with a ICMJE recognized registry, the UMIN-CTR, with the number UMIN000022557.
authors.affiliation: Department of Neurology, Shinko Hospital Kobe, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Matsumoto
authors.affiliation: Department of Clinical Neuroscience, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan.
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Murakami
authors.affiliation: Department of Clinical Neuroscience, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Koizumi
authors.affiliation: Department of Neurology, Shinko Hospital Kobe, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Clinical Neuroscience, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan.
authors.forename: Yuishin
authors.initials: Y
authors.lastname: Izumi
authors.affiliation: Department of Clinical Neuroscience, Institute of Health Biosciences, The University of Tokushima Graduate School Tokushima, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kaji
keywords: blepharospasm; dystonia; edrophonium