OVEMP in Myasthenia

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.

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Key information

Conditions

Myasthenia Gravis, Ocular Autoimmune Diseases Autoimmune Diseases of the Nervous System Immune System Diseases Myasthenia Gravis Neoplasms Neoplasms by Site Nervous System Diseases Nervous System Neoplasms Neurodegenerative Diseases Neuromuscular Diseases Neuromuscular Junction Diseases Paraneoplastic Syndromes Paraneoplastic Syndromes, Nervous System

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital Zurich, Ophthalmology/Neurology Department

Zurich, 8091, Switzerland

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Informed Consent as documented by signature
Patients with diplopia and/or ptosis suspicious for myasthenia gravis.

Exclusion criteria

Vestibular disorders
Significant systemic myasthenia symptoms (respiration or swallowing difficulties) unable to undergo oVEMP testing.
Patients with significant cardiac or respiratory disease will be excluded from the Tensilon test as part of the reference standard.
Women who are pregnant or breast feeding.

Treatment and study plan

Ocular vestibular evoced myogenic potentials

Diagnostic Test

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.

Primary outcomes

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

Sponsors and collaborators

Lead sponsor

University of Zurich

Other

Registry information

Official study title

Diagnostic Accuracy of Repetitive Ocular Vestibular Evoked Myogenic Potentials in Myasthenia Gravis (OMG Study)

Important dates

Study start: 2016
Primary completion: 2020
First posted: Feb 10, 2017
Registry last updated: Jan 11, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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