Does Sound Conditioning Protect Against Temporary Hearing Damage

Study Overview
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Brief Summary
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This research project will contribute to the research surrounding the effect on the ear after noise exposure. This ever-growing field of research has never been more applicable than now with the increase of recreational noise exposure. Noise is the leading cause of preventable hearing loss and excessive occupational noise along with recreational noise exposure can cause a devastating disability. The World Health Organisation (WHO) estimates 1.1 billion young people could be at risk of hearing loss due to unsafe listening practices. One of the mechanisms that could increase the resistance against noise induced hearing loss is 'sound conditioning'. Animal studies have found that prior exposure to low level noise over a period of a few weeks can 'condition' the ear. This conditioning then reduces the susceptibility to high level exposure i.e. strengthening the ear. In this study, the investigators aim to determine whether previous exposure to loud noise can condition the human ear, reducing the temporary hearing loss and temporary tinnitus (ringing in the ear) that sometimes occurs after attending a loud nightclub or live music event. There are many implications of this research. For one it will allow us to understand more about the susceptibility to exposure of sounds and the resistance against noise induced hearing loss. This will mean that the investigators can enable appropriate interventions if necessary. For example, individuals who are more susceptible due to low prior exposure may be advised that they are at risk, and encouraged to use hearing protection. Being able to learn more about the impacts of noise with hearing and educate others such as understanding the impacts from high-level exposure.

Detailed Description
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STUDY OBJECTIVES i) To identify if there is a relationship between previous sound exposure levels and TTS and tinnitus after a single loud noise event. STUDY DESIGN Type of Study: Basic Science Study, Between Groups Trial Aim: To investigate if previous sound conditioning reduces susceptibility to TTS and tinnitus when comparing to those without prior exposure. Purpose: To increase understanding on the effects of noise exposure. Duration: Data collection will be completed by February 2020 Participants: 40 normal hearing young (18-35) participants in good general health and fluent in English. Spilt into groups of two. One group (20, 10f:10m) with previous exposure i.e. nightclubs ++, the other group (20, 10f:10m) with less exposure measured through NESI.

Official Title
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Does Sound Conditioning Protect Against Temporary Hearing Damage

Conditions
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Hearing Loss, Noise-Induced

Intervention / Treatment
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* Diagnostic Test: Session One Test Battery
* Diagnostic Test: Session Two Test Battery
* Diagnostic Test: Session Three Test Battery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-35 years old (as age can affect cochlea hair cell function) Healthy participants with no significant medical conditions 0.25 Hz to 8 kHz PTA in both ears have thresholds < 20 dB HL indicating normal hearing Otoscopy to ensure no otological abnormalities No exposure to abnormally loud sounds in the past 24 hours Full capacity to consent Able to speak fluent English so information sheets, consent forms and instructions are fully understood Previous intention to attend a loud noise event during the course of the study, without the use of hearing protection Exclusion Criteria: No permanent tinnitus or hyperacusis (sensitivity to loud sounds) which would mean participants are unable to undertake all testing and a high exposure event Any contraindications for testing i.e. excessive wax, infections One or more frequencies 0.25 Hz to 8 kHz > 20 dB HL in either ear Not involved in current research or have recently been involved in any research prior to recruitment

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| High Noise Exposure<br>One group (20, 10f:10m) with previous exposure i.e. nightclubs ++ | Diagnostic Test: Session One Test Battery<br>* Prior to noise exposure: Test battery - High-frequency audiometry, Distortion Product Otoacoustic Emissions, Middle Ear Muscle Reflex, Speech-in-Noise test, Tinnitus Functional Index (Around 35 minutes with breaks if required) Extended Frequency Audiometry (  8 min): Participants will be asked to press the button when they hear a sound through the headphones in a soundproof booth. DPOAE (  5 min): A small tip will be placed in participants' ear and they will hear a sound. The tip measures a response from hair cells in the cochlea and they will not need to do anything. MEMR (  8 min): A small tip placed in both ears and again a sound heard, however, this sound will gradually get louder until an involuntary muscle reflex is noted. Speech-in-Noise Test (  5 min): Participants asked to repeat back a list of words as best as they can. TFI (  8 min): Participants given a self-report sheet in which they have to fill out aspects of any tinnitus experienced.<br>Diagnostic Test: Session Two Test Battery<br>* Exposure at single loud music event (Important that this is part of participants' normal recreational routine, and specifically require that attendance is not prompted by participation in this study): Participants to use sound level meter provided from the Audiology Department at Charing Cross Hospital to measure sound levels inside the loud event. Morning after exposure: Repeat test battery from session one - Ideally as soon as event is over.<br>Diagnostic Test: Session Three Test Battery<br>* 1 week later (recovery): Repeat test battery.<br>|
| Low Noise Exposure<br>Group (20, 10f:10m) with less exposure measured through NESI | Diagnostic Test: Session One Test Battery<br>* Prior to noise exposure: Test battery - High-frequency audiometry, Distortion Product Otoacoustic Emissions, Middle Ear Muscle Reflex, Speech-in-Noise test, Tinnitus Functional Index (Around 35 minutes with breaks if required) Extended Frequency Audiometry (  8 min): Participants will be asked to press the button when they hear a sound through the headphones in a soundproof booth. DPOAE (  5 min): A small tip will be placed in participants' ear and they will hear a sound. The tip measures a response from hair cells in the cochlea and they will not need to do anything. MEMR (  8 min): A small tip placed in both ears and again a sound heard, however, this sound will gradually get louder until an involuntary muscle reflex is noted. Speech-in-Noise Test (  5 min): Participants asked to repeat back a list of words as best as they can. TFI (  8 min): Participants given a self-report sheet in which they have to fill out aspects of any tinnitus experienced.<br>Diagnostic Test: Session Two Test Battery<br>* Exposure at single loud music event (Important that this is part of participants' normal recreational routine, and specifically require that attendance is not prompted by participation in this study): Participants to use sound level meter provided from the Audiology Department at Charing Cross Hospital to measure sound levels inside the loud event. Morning after exposure: Repeat test battery from session one - Ideally as soon as event is over.<br>Diagnostic Test: Session Three Test Battery<br>* 1 week later (recovery): Repeat test battery.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PTA (EF) | Extended Frequency (EF) PTA - dBHL, Higher values = worse hearing thresholds. Measure thresholds in the three sessions. Compare these values between the two groups. | 2020 | 
| DPOAE | Distortion Product Otoacousic Emissions (DPOAE), Pass or Fail, fail = hearing thresholds > 30 dBHL. Measure results in the three sessions. Compare if there are any changes and compare values between the two groups. | 2020 | 
| TFI | Tinnitus Functional Index (TFI), Score out of 100, higher the score = larger problem with tinnitus. Measure TFI scores in the three sessions. Compare if there are any changes and compare values between the two groups. | 2020 | 
| MEMR | Middle Ear Muscle Reflex (MEMR), Present or not present, not present = reflex > 95 dB. Measure if MEMR is present/raised in the three sessions. Compare if there are any changes and compare values between the two groups. | 2020 | 
| SiN | Speech in Noise (SiN) Test, Score, higher the score = better the speech recognition. Measure SiN in the three sessions. Compare if there are any changes and compare values between the two groups. | 2020 |