title: Ocular vestibular evoked myogenic potentials as a test for myasthenia gravis.
abstract: OBJECTIVE
  To explore whether ocular vestibular evoked myogenic potentials (oVEMP) can be used to detect a decrement in the extraocular muscle activity of patients with myasthenia gravis (MG).
  
  
  METHODS
  Twenty-seven patients with MG, including 13 with isolated ocular and 14 with generalized MG, and 28 healthy controls participated. We applied repetitive vibration stimuli to the forehead and recorded the activity of the inferior oblique muscle with 2 surface electrodes placed beneath the eyes. To identify the oVEMP parameters with the highest sensitivity and specificity, we evaluated the decrement over 10 stimulus repetitions at 3 different repetition rates (3 Hz, 10 Hz, and 20 Hz).
  
  
  RESULTS
  Repetitive stimulation at 20 Hz yielded the best differentiation between patients with MG and controls with a sensitivity of 89% and a specificity of 64% when using a unilateral decrement of ≥15.2% as cutoff. When using a bilateral decrement of ≥20.4% instead, oVEMP allowed differentiation of MG from healthy controls with 100% specificity, but slightly reduced sensitivity of 63%. For both cutoffs, sensitivity was similar in isolated ocular and generalized MG.
  
  
  CONCLUSIONS
  Our study demonstrates that the presence of an oVEMP decrement is a sensitive and specific marker for MG. This test allows direct and noninvasive examination of extraocular muscle activity, with similarly good diagnostic accuracy in ocular and generalized MG. Thus, oVEMP represents a promising diagnostic tool for MG.
  
  
  METHODS
  This study provides Class III evidence that oVEMP testing accurately identifies patients with MG with ocular symptoms (sensitivity 89%, specificity 64%).
authors.affiliation: From the Departments of Ophthalmology (Y.V., K.L., K.P.W.) and Neurology (Y.V., H.H.J., D.S., K.P.W.), University Hospital Zurich, University of Zurich, Switzerland; Department of Neurology (S.M.R.), Royal Prince Alfred Hospital, Sydney; and the Central Clinical School (S.M.R.), University of Sydney, Australia.
authors.forename: Yulia
authors.initials: Y
authors.lastname: Valko
authors.affiliation: From the Departments of Ophthalmology (Y.V., K.L., K.P.W.) and Neurology (Y.V., H.H.J., D.S., K.P.W.), University Hospital Zurich, University of Zurich, Switzerland; Department of Neurology (S.M.R.), Royal Prince Alfred Hospital, Sydney; and the Central Clinical School (S.M.R.), University of Sydney, Australia.
authors.forename: Sally M
authors.initials: SM
authors.lastname: Rosengren
authors.affiliation: From the Departments of Ophthalmology (Y.V., K.L., K.P.W.) and Neurology (Y.V., H.H.J., D.S., K.P.W.), University Hospital Zurich, University of Zurich, Switzerland; Department of Neurology (S.M.R.), Royal Prince Alfred Hospital, Sydney; and the Central Clinical School (S.M.R.), University of Sydney, Australia.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Jung
authors.affiliation: From the Departments of Ophthalmology (Y.V., K.L., K.P.W.) and Neurology (Y.V., H.H.J., D.S., K.P.W.), University Hospital Zurich, University of Zurich, Switzerland; Department of Neurology (S.M.R.), Royal Prince Alfred Hospital, Sydney; and the Central Clinical School (S.M.R.), University of Sydney, Australia.
authors.forename: Dominik
authors.initials: D
authors.lastname: Straumann
authors.affiliation: From the Departments of Ophthalmology (Y.V., K.L., K.P.W.) and Neurology (Y.V., H.H.J., D.S., K.P.W.), University Hospital Zurich, University of Zurich, Switzerland; Department of Neurology (S.M.R.), Royal Prince Alfred Hospital, Sydney; and the Central Clinical School (S.M.R.), University of Sydney, Australia.
authors.forename: Klara
authors.initials: K
authors.lastname: Landau
authors.affiliation: From the Departments of Ophthalmology (Y.V., K.L., K.P.W.) and Neurology (Y.V., H.H.J., D.S., K.P.W.), University Hospital Zurich, University of Zurich, Switzerland; Department of Neurology (S.M.R.), Royal Prince Alfred Hospital, Sydney; and the Central Clinical School (S.M.R.), University of Sydney, Australia. konrad.weber@usz.ch.
authors.forename: Konrad P
authors.initials: KP
authors.lastname: Weber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000175:diagnosis* / Q000503:physiopathology*; D009801:Oculomotor Muscles / Q000503:physiopathology*; D010812:Physical Stimulation / Q000379:methods*; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014732:Vibration; D055815:Young Adult