OVEMP in Myasthenia

Myasthenia Gravis, Ocular Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03049956
• Other study ID #: 2016-01109
• Status: Completed
• Phase: N/A
• Start date: November 1, 2016

Study information

• Verified date: January 2021
• Source: University of Zurich
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 96
• Est. primary completion date: December 31, 2020
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

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.

Related Conditions & MeSH terms

• Muscle Weakness
• Myasthenia Gravis
• Myasthenia Gravis, Ocular

Intervention

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.

Locations

Country	Name	City	State
Switzerland	University Hospital Zurich, Ophthalmology/Neurology Department	Zurich

Sponsors (1)

Lead Sponsor	Collaborator
University of Zurich

Country where clinical trial is conducted

Switzerland, 

References & Publications (1)

Valko Y, Rosengren SM, Jung HH, Straumann D, Landau K, Weber KP. Ocular vestibular evoked myogenic potentials as a test for myasthenia gravis. Neurology. 2016 Feb 16;86(7):660-8. doi: 10.1212/WNL.0000000000002383. Epub 2016 Jan 20. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Decrement (as quantified in %) of repetitive 20 Hz ocular vestibular-evoked myogenic potentials (oVEMP)	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	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).