OVEMP in Myasthenia
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|ClinicalTrials.gov Identifier: NCT03049956|
Recruitment Status : Recruiting
First Posted : February 10, 2017
Last Update Posted : February 10, 2017
Myasthenia gravis is an autoimmune disorder of neuromuscular transmission, characterized by fluctuating muscle weakness and fatigability. In isolated ocular myasthenia, when only the extraocular muscles are involved, most common ancillary tests, such as acetylcholine receptor autoantibodies and repetitive nerve stimulation, are often negative.
A simple, quick and non-invasive test for ocular myasthenia based on ocular vestibular evoked myogenic potentials (oVEMP) was recently developed.
The main goal of the study is to validate repetitive oVEMP stimulation in a blinded diagnostic accuracy study in order to facilitate early and accurate diagnosis of ocular myasthenia.
|Condition or disease||Intervention/treatment||Phase|
|Myasthenia Gravis, Ocular||Diagnostic Test: Ocular vestibular evoced myogenic potentials||Not Applicable|
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||200 participants|
|Intervention Model:||Single Group Assignment|
|Masking Description:||Blinded diagnostic accuracy study (index test vs. reference standard).|
|Official Title:||Diagnostic Accuracy of Repetitive Ocular Vestibular Evoked Myogenic Potentials in Myasthenia Gravis (OMG Study)|
|Actual Study Start Date :||November 1, 2016|
|Estimated Primary Completion Date :||December 31, 2019|
|Estimated Study Completion Date :||December 31, 2019|
|Experimental: Patients with clinical suspicion of ocular myasthenia gravis||
Diagnostic Test: Ocular vestibular evoced myogenic potentials
The oVEMP technique is an accepted standard for testing otolith function in vestibular patients. It represents a quick, simple and non-invasive technique utilizing repetitive stimulation of the otolith organs with bone-conducted vibration to elicit an extraocular muscle response. Repetitive oVEMP stimulation leads to a characteristic decrement in patients with myasthenia, which can be quantified with surface electromyography from the inferior oblique muscle underneath the eye.
- Decrement (as quantified in %) of repetitive 20 Hz ocular vestibular-evoked myogenic potentials (oVEMP) [ Time Frame: The primary outcome measure (index test oVEMP) will be assessed at baseline, in conjunction with reference standard/standard clinical workup (including blood analysis, neurological exam, edrophonium test, electromyography, single-fiber electromyography). ]oVEMP have been established as a standard clinical test of otolith function. Based on this technique, repetitive oVEMP stimulation, as a novel method for detecting ocular myasthenia gravis, was recently developed. Using this method, a response decrement in extraocular muscles can be quantified. The method is based on the conventional oVEMP montage with surface electrodes placed below the eyes. In order to elicit a response decrement, trains of ten bone-conducted vibration bursts at repetition rates of 20Hz will be applied with a hand-held 'minishaker' to the forehead. The oVEMP in response to these repetitive vibration stimuli will be measured in sustained upgaze from both inferior oblique muscles via surface electrodes. The magnitude of the decrement will be calculated as the difference between the amplitude of the second stimulus repetition and the mean amplitude of the fifth to ninth stimulus repetition. For further Information see: Valko et al. 2016 PMID:26791146
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03049956
|Contact: Konrad P Weber, PD, MDfirstname.lastname@example.org|
|University Hospital Zurich, Ophthalmology/Neurology Department||Recruiting|
|Zurich, Switzerland, 8091|
|Contact: Konrad P Weber, PD, MD|