Investigating short latency subcortical vestibular projections in humans: what have we learned?

2019 ◽  
Vol 122 (5) ◽  
pp. 2000-2015 ◽  
Author(s):  
James G. Colebatch ◽  
Sally M. Rosengren
Keyword(s):  
Brain Stem ◽  
Physiological Role ◽  
Vestibular Function ◽  
Short Latency ◽  
Vestibular Evoked Myogenic Potentials ◽  
Ocular Vemp ◽  
Motor Unit Firing ◽  
Cervical Vemp ◽  
Noninvasive Assessment

Vestibular evoked myogenic potentials (VEMPs) are now widely used for the noninvasive assessment of vestibular function and diagnosis in humans. This review focuses on the origin, properties, and mechanisms of cervical VEMPs and ocular VEMPs; how these reflexes relate to reports of vestibular projections to brain stem and cervical targets; and the physiological role of (otolithic) cervical and ocular reflexes. The evidence suggests that both VEMPs are likely to represent the effects of excitation of irregularly firing otolith afferents. While the air-conducted cervical VEMP appears to mainly arise from excitation of saccular receptors, the ocular VEMP evoked by bone-conducted stimulation, including impulsive bone-conducted stimuli, mainly arises from utricular afferents. The surface responses are generated by brief changes in motor unit firing. The effects that have been demonstrated are likely to represent otolith-dependent vestibulocollic and vestibulo-ocular reflexes, both linear and torsional. These observations add to previous reports of short latency otolith projections to the target muscles in the neck (sternocleidomastoid and splenius) and extraocular muscles (the inferior oblique). New insights have been provided by the investigation and application of these techniques.

scholarly journals Assessment of cervical and ocular vestibular evoked myogenic potentials in migraine patients

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Doaa Elmoazen ◽  
Hesham Kozou ◽  
Jaidaa Mekky ◽  
Dalia Ghanem
Keyword(s):  
Vestibular Function ◽  
Vestibular Dysfunction ◽  
Peak Amplitude ◽  
Vestibular Evoked Myogenic Potentials ◽  
Healthy Controls ◽  
Latency Difference ◽  
Significant Difference ◽  
Cervical Vemp ◽  
Vestibular Symptoms ◽  
Function Assessment

Abstract Background Patients suffering from vestibular migraine (VM) are known to have various vestibular test abnormalities interictally and ictally. Recently, vestibular evoked myogenic potentials (VEMPs) have become accepted as a valid method for otolith function assessment. Many studies have identified various vestibular symptoms and laboratory abnormalities in migraineurs. Since migraineurs with no accompanying vestibular symptoms might exhibit subclinical vestibular dysfunction, we investigated vestibular function using ocular and cervical VEMPs in migraine patients. The aim was to study cervical VEMP and occular VEMP in migraineurs with and without vestibular symptoms interictally. Results Migraine and VM patients showed significantly longer P13 latency of cVEMP compared to controls. A statistically significant cVEMP interaural P13 latency difference was found in VM compared to healthy controls. Cervical VEMP N23 latency, peak-to-peak amplitude, interaural N23 latency, and amplitude asymmetric ratio did not show any significant difference in migraine and VM patients compared to healthy controls as well as no significant difference across the three groups regarding oVEMP parameters. Conclusions Abnormal interictal cVEMP results in migraineurs might indicate subclinical vestibulo-collic pathway dysfunction.

Vestibular evoked myogenic potentials in response to laterally directed skull taps

2002 ◽  
Vol 12 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Krister Brantberg ◽  
Arne Tribukait
Keyword(s):  
Vestibular Function ◽  
Normal Subjects ◽  
Short Latency ◽  
The Other ◽  
Vestibular Evoked Myogenic Potentials ◽  
Vestibular Loss ◽  
Skin Electrodes ◽  
Function Loss ◽  
Relaxation Responses ◽  
Muscular Responses

In recent years it has been demonstrated that loud clicks generate short latency vestibular evoked myogenic potentials (VEMP). It has also been demonstrated that midline forehead skull tap stimulation evokes similar VEMP. In the present study, the influence of skull tap direction on VEMP was studied in 13 normal subjects and in five patients with unilateral vestibular loss. Gentle skull taps were delivered manually above each ear on the side of the skull. The muscular responses were recorded over both sternocleidomastoid muscles using skin electrodes. Among the normals, laterally directed skull taps evoked “coordinated contraction-relaxation responses”, i.e. skull taps on one side evoked a negative-positive “inverted” VEMP on that side and a positive-negative "normal" VEMP on the other side. Among patients with unilateral vestibular function loss, skull taps above the lesioned ear evoked similar coordinated contraction-relaxation responses. However, skull taps above the healthy ear did not evoke that type of response. These findings suggest that laterally directed skull taps activate mainly the contralateral labyrinth.

scholarly journals Quantitative Vestibular Function Testing in the Pediatric Population

2018 ◽  
Vol 39 (03) ◽  
pp. 257-274 ◽  
Author(s):  
Amanda Rodriguez ◽  
Kristen Janky
Keyword(s):  
Pediatric Population ◽  
Vestibular Function ◽  
Head Impulse Test ◽  
Caloric Test ◽  
Vestibular Loss ◽  
Head Impulse ◽  
Ocular Vemp ◽  
Cervical Vemp ◽  
Vestibular Function Testing ◽  
Function Testing

AbstractQuantitative tests of vestibular function include the caloric test, cervical and ocular vestibular evoked myogenic potential (VEMP), rotary chair, and head impulse test, either at the bedside or utilizing video head impulse test (vHIT). The purpose of this article is to provide an overview of how to perform these tests in children, including which tests are recommended based on the child's age and any modifications or considerations that can be made. A variety of clinical measures have been recommended as screening measures for vestibular loss, which will be reviewed. Symptom questionnaires designed to assess the functional impact of dizziness and vestibular loss in children will also be discussed. If a child complains of dizziness or if vestibular loss is suspected (either by case history or positive screening measure), vestibular function testing is warranted. For vestibular function testing, children aged 0 to 2 years typically receive rotary chair, cervical VEMP, and vHIT if a remote system is available. For children aged 3 to 7 years, vHIT, cervical VEMP, and ocular VEMP are completed, and for children aged 8+ years, vHIT, caloric testing if vHIT is normal, and cervical and ocular VEMP are completed. For all children, modifications to testing can be made, as needed.

scholarly journals Novel transmitters in brain stem vagal neurocircuitry: new players on the pitch

2018 ◽  
Vol 315 (1) ◽  
pp. G20-G26 ◽  
Author(s):  
Mehmet Bülbül ◽  
R. Alberto Travagli
Keyword(s):  
Brain Stem ◽  
Gastrointestinal Motility ◽  
Physiological Role ◽  
Neuropeptide S ◽  
Motor Functions ◽  
Stress Responsiveness ◽  
Gastrointestinal Motor ◽  
Major Increase ◽  
As Stress

The last few decades have seen a major increase in the number of neurotransmitters and neuropeptides recognized as playing a role in brain stem neurocircuits, including those involved in homeostatic functions such as stress responsiveness, gastrointestinal motility, feeding, and/or arousal/wakefulness. This minireview will focus on the known physiological role of three of these novel neuropeptides, i.e., apelin, nesfatin-1, and neuropeptide-S, with a special emphasis on their hypothetical roles in vagal signaling related to gastrointestinal motor functions.

scholarly journals Parameters of Off-Vertical Axis Rotation in Unilateral and Bilateral Vestibulopathy and Their Correlation with Vestibular Evoked Myogenic Potentials

2021 ◽  
Vol 10 (4) ◽  
pp. 756
Author(s):  
Shin Hye Kim ◽  
Sang-Yeon Lee ◽  
Ji-Soo Kim ◽  
Ja-Won Koo
Keyword(s):  
Vertical Axis ◽  
Vestibular Evoked Myogenic Potentials ◽  
Healthy Controls ◽  
Bilateral Vestibulopathy ◽  
Absolute Value ◽  
Ocular Vemp ◽  
Vestibular Hypofunction ◽  
Cervical Vemp ◽  
Interaural Difference ◽  
Axis Rotation

Off-vertical axis rotation (OVAR) is a laboratory test to assess the otolith function. This study aimed to analyze the parameters of OVAR in patients with unilateral vestibular hypofunction (UVH) and bilateral vestibulopathy (BVP), and to correlate the parameters of OVAR with those of VEMPs. Ten healthy volunteers, 41 UVH, and 13 BVP patients performed OVAR. Bias component (BIC) and modulation component (MOC) of UVH and BVP patients were compared with those of healthy controls. BIC and MOC were correlated with amplitude and interaural difference (IAD) of cervical VEMP (cVEMP) and ocular VEMP (oVEMP). In UVH patients, the direction of BICs to affected side rotation were reversed and the absolute value of BICs were decreased when they were compared to healthy controls. In BVP patients, BICs were markedly attenuated. MOCs were not changed in UVH and BVP patients. There was no statistically significant correlation between VEMPs and OVAR.

Sports Concussions (TBI), Imbalance, and Dizziness

2015 ◽  
Vol 25 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Steven M. Doettl
Keyword(s):  
Assessment Tools ◽  
Vestibular Evoked Myogenic Potentials ◽  
Post Injury ◽  
Management Tools ◽  
Concussion Management ◽  
Post Concussion Syndrome ◽  
Behavioral Marker ◽  
Valid Assessment ◽  
Injury Assessment

It has been widely accepted that the assessment of balance after concussion plays a large role in determining deficit. Qualitative balance assessments have been an established piece of the post-injury assessment as a clinical behavioral marker of concussion for many years. Recently more specific guidelines outlining the role of balance evaluation in concussion identification and management have been developed as part of concussion management tools. As part of the ongoing development of concussions protocols, quantitative assessment of balance function following concussion has also been identified to have an important role. Frequently imbalance and dizziness reported following concussion is assumed to be associated with post-concussion syndrome (PCS). While imbalance and dizziness are common complaints in PCS, they can also be a sign of additional underlying pathology. In cases of specific dizziness symptoms or limited balance recovery beyond the initial post-concussive period, a quantitative vestibular assessment may also be needed. Electronystagmography and videonystagmography (ENG/VNG), rotary chair testing (RCT), and vestibular evoked myogenic potentials (VEMPs) have all been identified as valid assessment tools for vestibular dysfunction following traumatic brain injury (TBI). The assessment of balance and dizziness following sports-related concussions is an integral piece of the puzzle for removal from play, assessment of severity, and management.

Physiological Role of Cyclic Electron Flow in Higher Plants

2012 ◽  
Vol 30 (1) ◽  
pp. 100
Author(s):  
Wei HUANG ◽  
Shi-Bao ZHANG ◽  
Kun-Fang CAO
Keyword(s):  
Higher Plants ◽  
Electron Flow ◽  
Physiological Role ◽  
Cyclic Electron Flow

The Renal Outer Medullary Potassium Channel (ROMK): An Intriguing Pharmacological Target for an Innovative Class of Diuretic Drugs

2018 ◽  
Vol 25 (23) ◽  
pp. 2627-2636 ◽  
Author(s):  
Vincenzo Calderone ◽  
Alma Martelli ◽  
Eugenia Piragine ◽  
Valentina Citi ◽  
Lara Testai ◽  
...  
Keyword(s):  
Physiological Role ◽  
Clinical Use ◽  
Diuretic Activity ◽  
First Line ◽  
Potassium Homeostasis ◽  
Diuretic Drugs ◽  
Pharmacological Target ◽  
Diuretic Agents ◽  
Effective Drugs

In the last four decades, the several classes of diuretics, currently available for clinical use, have been the first line option for the therapy of widespread cardiovascular and non-cardiovascular diseases. Diuretic drugs generally exhibit an overall favourable risk/benefit balance. However, they are not devoid of side effects. In particular, all the classes of diuretics cause alteration of potassium homeostasis. <p> In recent years, understanding of the physiological role of the renal outer medullary potassium (ROMK) channels, has shown an intriguing pharmacological target for developing an innovative class of diuretic agents: the ROMK inhibitors. This novel class is expected to promote diuretic activity comparable to (or even higher than) that provided by the most effective drugs used in clinics (such as furosemide), with limited effects on potassium homeostasis. <p> In this review, the physio-pharmacological roles of ROMK channels in the renal function are reported, along with the most representative molecules which have been currently developed as ROMK inhibitors.

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