Vestibular evoked myogenic potentials (VEMPs)

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Identifier NOVEL_VEMPS
Title Vestibular evoked myogenic potentials (VEMPs)
Subject Vestibular lab testing, Vestibular Evoked Myogenic Potentials (VEMPs)
Creator Bryan Ward, MD, Department of Otolaryngology - Head & Neck Surgery, Division of Neuro-otology, The Johns Hopkins School of Medicine (Gold Collection)
Description Vestibular-evoked myogenic potentials (VEMP) are electromyographic potential reflex tests that reflect the function of the saccule in cervical VEMP and the utricle in ocular VEMP.1 In the cervical VEMP an inhibitory reflex is evoked from the saccule to the sternocleidomastoid ipsilateral to the stimulus. The most common stimulus is a sound (either a 500 Hz tone burst or a broad-band click) played to the ear on the side being tested. The patient is instructed to contract their sternocleidomastoid muscle while the stimulus is played, and an average of a series of responses is recorded using surface electrodes on the neck (Figure 1). A characteristic biphasic waveform is assessed with a latency of the peaks at 13 and 23 milliseconds (Figure 2a). Typically a threshold of sound intensity is obtained at which the characteristic waveform is observed. The saccule functions similar to a hearing organ in fish, responding to lower frequency stimuli and the cervical VEMP may be a vestigial reflex. An absent response at the loudest stimulus level can reflect impairment of the saccule or the inferior vestibular nerve; however, an absent response can also reflect inadequate activity of the sternocleidomastoid muscle, middle ear disease, or a lesion along the pathway from the saccule to the central vestibulospinal pathways. An especially large response at a low threshold (i.e., a present waveform at a much weaker stimulus intensity) is typical of superior semicircular canal dehiscence syndrome, in which a hole in the bony superior semicircular canal creates a new low impedance pathway in the ear.
Publisher Spencer S. Eccles Health Sciences Library, University of Utah
Date 2018-03
Format application/pdf
Rights Management Copyright 2018. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright
Collection Neuro-ophthalmology Virtual Education Library: NOVEL http://NOVEL.utah.edu
Language eng
ARK ark:/87278/s66d9smh
Setname ehsl_novel_gold
Date Created 2018-03-15
Date Modified 2018-05-31
ID 1306743
Reference URL https://collections.lib.utah.edu/ark:/87278/s66d9smh
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