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Anatomy and Physiology of Balance
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Nishchay Mehta, Andrew Forge, Jonathan Gale
The orientation of hair cells in the utricle are such that horizontal translation (e.g. standing face forward on a skateboard and being pulled to the left or right) is best detected. In addition, the utricle provides continuous information about horizontal body position in relation to gravitational centre (e.g. awaking from sleep lying on side). This allows one to detect that they are tilted sideways off the vertical. The utricle provides sensory input for the utriculo-ocular reflex that causes eyes to move in the opposite direction to the side of lateral translation and maintain visual fixation. The ocular vestibular myogenic evoked potential (VEMP) is a test of the utriculo-ocular reflex, and the cervical VEMP is likely more dominated by the saccule.
Clinical Test Paradigms and Problems: Human Otoprotection Studies
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Colleen G. Le Prell, Kathleen C. M. Campbell
There are a host of clinical tests that precisely measure the functional status of the different parts of the vestibular system and they are often combined in a battery that includes electronystagmography (ENG) or videonystagmography (VNG), rotational chair tests, and computerized dynamic posturography [or, test of balance (TOB)] or other postural testing. Vestibular-evoked myogenic potential (VEMP) tests might also be considered. VEMP tests are actually auditory evoked potential tests as the VEMP is a sound-evoked muscle reflex. During ocular VEMP (oVEMP) tests, electrodes are placed over the inferior oblique muscles to measure utricular function. During cervical VEMP (cVEMP) tests, electrodes are placed over the sternocleidomastoid muscles to measure saccular function. These tests are relatively newer and are not discussed further here. However, a brief description of each of the other tests, and an introduction to survey strategies is provided below.
Case 46
Published in Simon Lloyd, Manohar Bance, Jayesh Doshi, ENT Medicine and Surgery, 2018
Simon Lloyd, Manohar Bance, Jayesh Doshi
A second test commonly used to see if the SCD is functionally ‘open’ are the vestibular evoked myogenic potentials (VEMPs). These can be cervical or ocular but the cervical VEMPs are most commonly used. The following shows VEMP responses which are abnormally hypersensitive (present even at 65 dB nHL) in the left ear. The lowest level at which responses can be detected depends on the protocol used (tone bursts vs. clicks, frequency etc.), but both the right and left ears here show abnormally low thresholds.
Cervical and ocular vestibular evoked myogenic potential: A comparison of narrowband chirp, broadband chirp, tone burst and click stimulation
Published in International Journal of Audiology, 2023
Tarryn Marisca Reddy, Barbara Heinze, Leigh Biagio-de Jager, Leen Maes
The vestibular evoked myogenic potential (VEMP) is a clinical vestibular function test used to assist in the identification and diagnosis of vestibular pathologies by evaluating otolith function (Ozgur et al. 2015; Walther and Cebulla 2016). The cervical VEMP (cVEMP) is mediated by a vestibulocervical reflex pathway that includes the saccular macula, inferior vestibular nerve, the lateral vestibular nucleus, the lateral vestibulospinal tract, and the motor-neurons of the ipsilateral sternocleidomastoid (SCM) muscle (Akin, Murnane, and Proffitt 2003). Vestibular evoked myogenic potentials can also be recorded from extraocular muscles, as part of the linear vestibulo-ocular reflex pathway by placing electrodes around the eyes and is referred to as ocular VEMP (oVEMP), which predominantly reflects utricular function (Rosengren, Welgampola, and Colebatch 2010).
Topography of the lesion in idiopathic sudden sensorineural hearing loss
Published in Acta Oto-Laryngologica, 2020
Ayse Pelin Yigider, Mehmet Keskin, Levent Kufeciler, Hasan Emre Kocak
VEMPs have been used to test the vestibular system integrity. Inferior and superior vestibular neural pathways have been clinically evaluated separately by c-vemp and o-vemp, respectively [1,5]. In the present study, we have examined vestibular system in ISSHNL patients without vertigo using c-vemp and o-vemp. It is well-known that inferior vestibular nerve pathway is frequently involved in SSNHL due to the close-proximity of saccule to the cochlear base [8]. Our results were consistent with the literature that latencies and amplitudes of c-vemp waves were distorted on the affected ear, however o-vemp latencies were similar on both sides. Additionally, it was shown that even in the absence of vestibular symptoms, saccule and/or inferior vestibular nerve pathway is involved in the natural history of SSNHL.
Vestibular evoked myogenic potentials: what are they for? An opinion; a hypothesis
Published in Acta Oto-Laryngologica, 2020
In order to detect C and OVEMPs, the individual is instructed to carry out tasks which are rarely, if ever, physiologically performed in life. Persistent tonic activity of the sternomastoid muscle on one side is hardly ever undertaken as a normal function. Similarly, maximally elevating the eyes only, without lifting the head, is only done for a fraction of a second before the head is raised under normal circumstances. In short, the tasks which are used to demonstrate C and OVEMPs are aphysiological. VEMP tests consist of putting muscles in extreme positions and then stimulating the reflex by sound (CVEMPs) or sound and vibration (OVEMPs). In these extreme aphysiological muscle activities, an intrinsic system of suppression for internal sounds has not been developed because it is unnecessary, and therefore, suppression does not occur. My hypothesis is that this is why VEMP responses can be measured in these extreme situations.