Activation Technique in cVEMPs

Study Overview
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Brief Summary
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This study will investigate two different techniques used for eliciting sternocleidomastoid (SCM) muscle contraction. Sustained contraction of the SCM muscle is necessary for accurate recording of cervical vestibular evoked myogenic potentials (cVEMPs). These responses are used clinically to assess the function of structures within the vestibular system. The British Society of Audiology (BSA) guidelines recommend the head turn and head raise techniques as effective methods for eliciting SCM contraction. However, they do not recommend which technique to employ, leaving that to the discretion of the clinician. The purpose of this study is to determine which activation technique to recommend in the local standard operating procedure on cVEMP testing developed by the Audiology and Vestibular Function Testing service based at the Royal Liverpool University Hospital. Healthy volunteers will be recruited to the study. The study will be conducted at the Royal Liverpool University Hospital, Liverpool, UK. The participants will each be invited to attend one appointment in which they will undergo cVEMP testing, performed using each activation technique in turn. After testing the participants will be asked to complete a questionnaire in which they will comment on their experience of performing each technique and assign each a tolerability rating.

Official Title
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An Investigation Into the Effect of the Head Raise and Head Turn Activation Techniques on Quality of Elicited Cervical Vestibular Evoked Myogenic Potentials (cVEMPs)

Conditions
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Activation Technique in cVEMP Testing

Intervention / Treatment
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* Diagnostic Test: Head Turn Activation Technique
* Diagnostic Test: Head Raise Activation Technique


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant is willing and able to give informed consent for participation in the study. Able (in the Investigators opinion) and willing to comply with all study requirements. Male, female or non-binary, aged 18-60 years old. Exclusion Criteria: Pain, sore areas, broken skin at the sites of contact with skin electrodes Devices, e.g. cochlear implants, which may cause electrical interference Exclusion criteria to cVEMP procedure : Conductive hearing loss of middle ear origin Sensitivity to sounds e.g. tinnitus, hyperacusis etc. Cervical spine problems Exclusion criteria to tympanometry procedure : Occlusion of the external auditory canal Otorrhoea Otalgia Excessive wax Within two months of ear surgery

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Raise-Turn Sequence<br>Participant performs cVEMP twice using the head raise activation technique followed by the head turn activation technique. | Diagnostic Test: Head Turn Activation Technique<br>* Participant sat upright with head turned to the side through 45 degrees. They are presented with an auditory stimulus delivered using insert earphones and their cVEMP response is recorded using skin electrodes.<br>Diagnostic Test: Head Raise Activation Technique<br>* Participant assumes caloric test position (30 degrees from horizontal) with head raised. Participant is presented with an auditory stimulus delivered using insert earphones and their cVEMP response is recorded using skin electrodes.<br>|
| Experimental: Turn-Raise Sequence<br>Participant performs cVEMP twice using the head turn activation technique followed by the head raise activation technique. | Diagnostic Test: Head Turn Activation Technique<br>* Participant sat upright with head turned to the side through 45 degrees. They are presented with an auditory stimulus delivered using insert earphones and their cVEMP response is recorded using skin electrodes.<br>Diagnostic Test: Head Raise Activation Technique<br>* Participant assumes caloric test position (30 degrees from horizontal) with head raised. Participant is presented with an auditory stimulus delivered using insert earphones and their cVEMP response is recorded using skin electrodes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cVEMP signal quality | Ratio of cVEMP signal power to background noise power | During single 1.5 hour appointment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cVEMP signal amplitude | P1-N1 amplitude measured from the P1 to N1 peaks | During single 1.5 hour appointment | 
| Activation technique tolerability rating | Participant reported tolerability will be scored on a four-point LIKERT scale ranging from 1 (highly intolerable) to 4 (highly tolerable) | During single 1.5 hour appointment | 
| Activation technique tolerability subjective feedback | Participant reported concerns shared through a post-test questionnaire | During single 1.5 hour appointment |