Effects of cochlear implants on otolith function as evaluated by vestibulo-ocular reflex and vestibular evoked myogenic potentials

ObjectiveTo determine the mechanism of ictal downbeat nystagmus in Ménière disease (MD), we compared the head impulse gain of the vestibulo-ocular reflex (VOR) for each semicircular canal between patients with (n = 7) and without (n = 70) downbeat nystagmus during attacks of MD.MethodsWe retrospectively analyzed the results of video-oculography, video head-impulse tests, and cervical vestibular-evoked myogenic potentials (VEMPs) in 77 patients with definite MD who were evaluated during an attack.ResultsPure or predominant downbeat nystagmus was observed in 7 patients (9%) with unilateral MD during the attacks. All 7 patients showed spontaneous downbeat nystagmus without visual fixation with a slow phase velocity ranging from 1.5 to 11.2°/s (median 5.4, interquartile range 3.7–8.5). All showed a transient decrease of the head impulse VOR gains for the posterior canals (PCs) in both ears (n = 4) or in the affected ear (n = 3). Cervical VEMPs were decreased in the affected (n = 2) or both ears (n = 2) when evaluated during the attacks. Downbeat nystagmus disappeared along with normalization of the VOR gains for PCs after the attacks in all patients. During the attacks, the head impulse VOR gains for the PC on the affected side were lower in the patients with ictal downbeat nystagmus than in those without (Mann-Whitney U test, p < 0.001), while the gains for other semicircular canals did not differ between the groups.ConclusionDownbeat nystagmus may be observed during attacks of MD due to an asymmetry in the vertical VOR or saccular dysfunction. MD should be considered in recurrent audiovestibulopathy and ictal downbeat nystagmus.

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Impaired vestibular responses in internuclear ophthalmoplegia

Neurology ◽

10.1212/wnl.0000000000004745 ◽

2017 ◽

Vol 89 (24) ◽

pp. 2476-2480 ◽

Cited By ~ 11

Author(s):

Seo-Young Choi ◽

Hyo-Jung Kim ◽

Ji-Soo Kim

Keyword(s):

Vestibular Evoked Myogenic Potentials ◽

Medial Longitudinal Fasciculus ◽

Subjective Visual Vertical ◽

Internuclear Ophthalmoplegia ◽

Horizontal Canal ◽

Head Impulse ◽

Ocular Tilt Reaction ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex ◽

Visual Vertical

Objective:To determine the role of the medial longitudinal fasciculus (MLF) in conveying vestibular signals.Methods:In 10 patients with isolated acute unilateral internuclear ophthalmoplegia (INO) due to an acute stroke, we performed comprehensive vestibular evaluation using video-oculography, head impulse tests with a magnetic search coil technique, bithermal caloric tests, tests for the ocular tilt reaction, and measurements of subjective visual vertical and cervical and ocular vestibular evoked myogenic potentials (VEMPs).Results:The head impulse gain of the vestibulo-ocular reflex (VOR) was decreased invariably for the contralesional posterior canal (PC) (n = 9; 90%) and usually for the ipsilesional horizontal canal (n = 5; 50%). At least one component of contraversive ocular tilt reaction (n = 9) or contraversive tilt of the subjective visual vertical (n = 7) were common along with ipsitorsional nystagmus (n = 5). Cervical or ocular VEMPs were abnormal in 5 patients.Conclusions:The MLF serves as the main passage for the high-acceleration VOR from the contralateral PC. The associations and dissociations of the vestibular dysfunction in our patients indicate variable combinations of damage to the vestibular fibers ascending or descending in the MLF even in strokes causing isolated unilateral INO.

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Ocular Vestibular Evoked Myogenic Potentials and Intravestibular Intralabyrinthine Schwannomas

Ear Nose & Throat Journal ◽

10.1177/014556131809700703 ◽

2018 ◽

Vol 97 (7) ◽

pp. E21-E25 ◽

Cited By ~ 2

Author(s):

Massimo Ralli ◽

Giuseppe Nola ◽

Massimo Fusconi ◽

Luca Sparvoli ◽

Giovanni Ralli

Keyword(s):

Contralateral Side ◽

Vestibular Evoked Myogenic Potentials ◽

Diagnostic Process ◽

Benign Tumors ◽

Average Delay ◽

Diagnostic Modality ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex ◽

Magnetic Resonance Imaging Mri ◽

The Right

Intravestibular intralabyrinthine schwannomas (ILSs) are uncommon benign tumors that arise from the sac-cular, utricular, and lateral and superior ampullary nerves. According to the literature, there is an average delay of 8 years between the onset of symptoms and diagnosis. Te diagnosis is based on an audiovestibular examination and magnetic resonance imaging (MRI). We describe a case of intravestibular ILS in which we included the ocular vestibular evoked myogenic potentials (oVEMPs) test in the diagnostic workup. The oVE-MPs test is a relatively new neurophysiologic diagnostic modality that evaluates the superior vestibular pathway and the ascending contralateral pathway through the vestibulo-ocular reflex. In our case, a 65-year-old man presented with progressive right-sided sensorineu-ral hearing loss, dizziness, and tinnitus and fullness in his right ear. Audiovestibular examination and MRI detected an intravestibular ILS on the right. We found that oVEMPs were absent on the contralateral side, which contributed to the diagnostic process. Te detection of oVEMPs can provide detailed information on the functionality of the macula of the utricle and the lateral and superior ampullary nerves, with a precise identification of the affected area. Based on our findings, we discuss the role of oVEMPs in the diagnosis of an intravestibular ILS.

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Vertigo and Imbalance

Clinical Neurophysiology ◽

10.1093/med/9780190259631.003.0052 ◽

2016 ◽

pp. 869-912

Author(s):

David A. Zapala

Keyword(s):

Semicircular Canal ◽

Muscle Tone ◽

Vestibular Evoked Myogenic Potentials ◽

Caloric Test ◽

Anatomy And Physiology ◽

Ocular Reflex ◽

Vestibular Tests ◽

Otolith Function ◽

Vestibular Ocular Reflex ◽

Central Compensation

Electrophysiologic testsests can be used to evaluate the function of each of the five vestibular sensory receptors in the labyrinth, in patients with dizziness and imbalance. Tests of semicircular canal function concentrate on vestibular ocular reflex behavior and include the bilateral, bi-thermal caloric test, video head impulse tests (vHIT), and rotary chair tests. Otolith function tests focus on changes in muscle tone and include the cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP). Interpreting vestibular tests requires an understanding of the underlying anatomy and physiology, and an appreciation of central compensation processes and their effects on each test. This chapter reviews the techniques and interpretation of vestibular testing to assess semicircular canal and otolith function and postural control.

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Sound-Evoked Responses in the Vestibulo-Ocular Reflex Pathways of Rats

Frontiers in Neuroscience ◽

10.3389/fnins.2021.741571 ◽

2021 ◽

Vol 15 ◽

Author(s):

Tianwen Chen ◽

Jun Huang ◽

Yue Yu ◽

Xuehui Tang ◽

Chunming Zhang ◽

...

Keyword(s):

Eye Movements ◽

Vestibular Nucleus ◽

Head Rotation ◽

Vestibular Evoked Myogenic Potentials ◽

Type I ◽

Evoked Responses ◽

Vestibular Neurons ◽

Ocular Reflex ◽

Discharge Rates ◽

Vestibulo Ocular Reflex

Vestibular evoked myogenic potentials (VEMP) have been used to assess otolith function in clinics worldwide. However, there are accumulating evidence suggesting that the clinically used sound stimuli activate not only the otolith afferents, but also the canal afferents, indicating canal contributions to the VEMPs. To better understand the neural mechanisms underlying the VEMPs and develop discriminative VEMP protocols, we further examined sound-evoked responses of the vestibular nucleus neurons and the abducens neurons, which have the interneurons and motoneurons of the vestibulo-ocular reflex (VOR) pathways. Air-conducted clicks (50–80 dB SL re ABR threshold, 0.1 ms duration) or tone bursts (60–80 dB SL, 125–4,000 Hz, 8 ms plateau, 1 ms rise/fall) were delivered to the ears of Sprague-Dawley or Long-Evans rats. Among 425 vestibular nucleus neurons recorded in anesthetized rats and 18 abducens neurons recorded in awake rats, sound activated 35.9% of the vestibular neurons that increased discharge rates for ipsilateral head rotation (Type I neuron), 15.7% of the vestibular neurons that increased discharge rates for contralateral head rotation (Type II neuron), 57.2% of the vestibular neurons that did not change discharge rates during head rotation (non-canal neuron), and 38.9% of the abducens neurons. Sound sensitive vestibular nucleus neurons and abducens neurons exhibited characteristic tuning curves that reflected convergence of canal and otolith inputs in the VOR pathways. Tone bursts also evoked well-defined eye movements that increased with tone intensity and duration and exhibited peak frequency of ∼1,500 Hz. For the left eye, tone bursts evoked upward/rightward eye movements for ipsilateral stimulation, and downward/leftward eye movements for contralateral stimulation. These results demonstrate that sound stimulation results in activation of the canal and otolith VOR pathways that can be measured by eye tracking devices to develop discriminative tests of vestibular function in animal models and in humans.

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