Does Sound Conditioning Protect Against Temporary Hearing Damage

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. The long-term effects of non-damaging lifetime noise exposures are unclear. Principally, this research will allow better understanding about noise susceptibility and resistance, allowing for appropriate interventions, thus improving care. For instance, an individual more susceptible due to low prior exposure can be advised of risks and encouraged to use hearing protection. This thesis will increase the knowledge base surrounding the impacts of noise on hearing and educate others in understanding these.

Study Overview

• Status: Completed
• Conditions: Hearing Loss, Noise-Induced
• Intervention / Treatment: Diagnostic test: Session Three Test Battery; Diagnostic test: Session One Test Battery; Diagnostic test: Session Two Test Battery

Detailed Description

Objective: This study explored if sound conditioning (recent noise exposure) protects individuals against temporary hearing damage.

Design: Participants attended two sessions in this between-group repeated measures trial; the first included a noise exposure structured interview. Five dependent variables were measured before and after attending a loud event: EFA, DPOAE, MEMR, QuickSIN and Tinnitus. It was hypothesised those with high recent noise exposure, Group 1 (noise unit > 0.323), would experience less temporary hearing damage than irregular attendees, Group 0.

Sample: Thirty-two normal hearing participants with a mean age of 26 ± 3.3 years (16 males, 16 females).

• Study Type: Observational
• Enrollment (Actual): 32

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom
    • St Mary's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

32 Normal Hearing, Healthy 18-35-year-olds.

Description

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 <= 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

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
High Noise Exposure; One group (16, 8f:8m) with previous exposure i.e. nightclubs ++	Diagnostic test: Session Three Test Battery; 1 week later (recovery): Repeat test battery.; Diagnostic test: Session One Test Battery; Prior to noise exposure: Test battery - High-frequency audiometry, Distortion Product Otoacoustic Emissions, Middle Ear Muscle Reflex, Speech-in-Noise test (Around 35 minutes with breaks if required); Extended Frequency Audiometry (~ 8 min), 0.25-16 kHz: Participants will be asked to press the button when they hear a sound through the headphones in a soundproof booth.; DPOAE (~ 5 min), 0.5-10 kHz: 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), 4 kHz: 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.; Tinnitus: Participants were also asked if they experience any tinnitus i.e. bilateral, lasting > 5 minutes. This was reported as Y/N.; Diagnostic test: Session Two Test Battery; 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 or sound level meter applications to measure sound levels inside the loud event. Morning after exposure: Repeat test battery from session one - Ideally as soon as event is over.
Low Noise Exposure; Group (16, 8f:8m) with less exposure measured through NESI	Diagnostic test: Session Three Test Battery; 1 week later (recovery): Repeat test battery.; Diagnostic test: Session One Test Battery; Prior to noise exposure: Test battery - High-frequency audiometry, Distortion Product Otoacoustic Emissions, Middle Ear Muscle Reflex, Speech-in-Noise test (Around 35 minutes with breaks if required); Extended Frequency Audiometry (~ 8 min), 0.25-16 kHz: Participants will be asked to press the button when they hear a sound through the headphones in a soundproof booth.; DPOAE (~ 5 min), 0.5-10 kHz: 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), 4 kHz: 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.; Tinnitus: Participants were also asked if they experience any tinnitus i.e. bilateral, lasting > 5 minutes. This was reported as Y/N.; Diagnostic test: Session Two Test Battery; 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 or sound level meter applications to measure sound levels inside the loud event. Morning after exposure: Repeat test battery from session one - Ideally as soon as event is over.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PTA (EF)	Extended Frequency (EF) PTA with results measured in dBHL where higher values mean worse hearing thresholds. Hearing thresholds were measured in the two sessions (unfortunately session three was not completed). A single dB HL value was calculated by averaging results across participants in each session (Extended frequency audiometry (EFA) comprised of averaging 2-16 kHz).	35 minutes per session
DPOAE (DP)	Distortion Product Otoacousic Emissions (DPOAE), DPOAEs were recorded bilaterally (at 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8 and 10 kHz) using the Otometrics Madsen Capella2. A daily check was performed in a 2 cc test cavity and tester's own ear to verify suitable recordings and ensure the probe was providing true responses. Measure results in the two sessions (unfortunately session three was not completed). DPOAE measurements were separated into distortion product (DP - dB SPL) and signal-to-noise ratio (SNR - dB) and averaged from 2-10 kHz. A single value was calculated by averaging results across participants in each session.	35 minutes per session
DPOAE (SNR)	Distortion Product Otoacousic Emissions (DPOAE), DPOAEs were recorded bilaterally (at 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8 and 10 kHz) using the Otometrics Madsen Capella2. A daily check was performed in a 2 cc test cavity and tester's own ear to verify suitable recordings and ensure the probe was providing true responses. Measure results in the two sessions (unfortunately session three was not completed). DPOAE measurements were separated into distortion product (DP - dB SPL) and signal-to-noise ratio (SNR - dB) and averaged from 2-10 kHz. A single value was calculated by averaging results across participants in each session.	35 minutes per session
MEMR	Middle Ear Muscle Reflex (MEMR) measured at 4 kHz bilaterally in dB SPL. A reflex was defined as > 0.02 ml compliance with appropriate morphology free from artefacts. Measure if MEMR is present/raised in the sessions. Averages between ears were also calculated for MEMR to give one result per participant for each session. A single value was then calculated by averaging results across participants in each session.	35 minutes per session
SiN	Speech in Noise (SiN) Test, Score. The sound field JBL Control One speakers and the Kamplex KM4 sound level meter (SLM) were calibrated via Guymark. Daily checks were conducted to assess speaker reliability when administering QuickSIN (Etymotic Research, 2001) with the signal and noise presented from the same speaker at 0° azimuths. The SLM confirmed speaker calibration and sound levels presented were within tolerances. Measure SiN in the sessions and a single value was calculated by averaging results across participants in each session.	35 minutes per session
Tinnitus	Participants were also asked if they experience any tinnitus i.e. bilateral, lasting > 5 minutes. This was reported as Y/N. An increase in underlying tinnitus, no change in underlying tinnitus and newly reported tinnitus was counted for each group in the second session. We aimed to assess the effect of conditioning on tinnitus change (i.e. increasing or not) at session 2, adjusting for tinnitus reported at session 1, age, gender, and event exposure. Session 1: existing underlying tinnitus reported. Session 2: Newly reported tinnitus and increase in underlying tinnitus.	35 minutes per session

Collaborators and Investigators

• Sponsor: Imperial College Healthcare NHS Trust
• Investigators: Principal Investigator: Emily Frost, Imperial College Healthcare NHS Trust

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2020
• Primary Completion (Actual): April 1, 2020
• Study Completion (Actual): April 1, 2020

Study Registration Dates

• First Submitted: March 11, 2019
• First Submitted That Met QC Criteria: March 15, 2019
• First Posted (Actual): March 18, 2019

Study Record Updates

• Last Update Posted (Estimated): December 12, 2024
• Last Update Submitted That Met QC Criteria: December 9, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Ear Diseases; Hearing Disorders; Hearing Loss, Sensorineural; Hearing Loss; Hearing Loss, Noise-Induced
• Other Study ID Numbers: 19CX4979

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No