CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-14). The draft was written by AI, the existence of all 2 cited sources was verified (1 access-limited, verified via index/summary and marked), and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2487 · Search date 2026-08-14 · Methodology v0.7

Concert earplugs,
does it really help with Prevention of temporary hearing-threshold shift immediately after amplified music exposure?

30-Second Summary
C
Evidence Grade C · 50 · Safety acceptable
In one festival RCT, earplugs reduced immediate temporary threshold shift and new tinnitus after amplified music.
Properly fitted earplugs are generally safe. Deep insertion or repeated use of contaminated plugs can irritate the ear canal, and reduced loudness should not be used to justify longer exposure near speakers.
What the
research shows
The grade is C. In a festival RCT with 4.5 hours of exposure averaging 100 dBA, temporary threshold shift at 3 and 4 kHz occurred in 4/50 ears (8%) with earplugs versus 22/52 ears (42%) without protection; the unprotected-to-earplug RR was 5.3 (95% CI 2.0-14.3). The effect was large, but it came from 51 people at one festival and measured a short-term surrogate, giving C with 50 points.
What the
ads claim
It is accurate to say the plugs reduced immediate post-event hearing change. It is not accurate to convert this into certain prevention of permanent hearing loss or assume every plug produces the same attenuation.
*

Useful facts when choosing a product

  • The trial plug was an MTV Soundkeepr product labeled for 18-dB noise reduction.
  • Average music exposure was 100 dBA for 4.5 hours.
  • Existing earplug verdicts mainly address sleep or delirium, not post-concert hearing threshold.
Gap Measurement · Verdict 2487 · C 50
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

Ramakers recruited 51 normal-hearing adults who did not intend to use earplugs, assigning 25 to MTV Soundkeepr plugs labeled for 18-dB attenuation and 26 to no protection. Mean sound exposure was 100 dBA for 4.5 hours. Temporary threshold shift occurred in 4/50 versus 22/52 ears, NNT 2.9. New tinnitus occurred in 3 versus 10 of 25 respondents per group, absolute difference 28 points (95% CI 3.6-49.0). Support involved UMC Utrecht, MTV Benelux, Van Boxtel, and Oticon Medical; MTV Soundkeepr supplied the plugs, and no conflicts were reported.

02

Why this is classified as C (50)

A small single-festival trial showed a large reduction in the prespecified primary threshold shift, but the endpoint was surrogate and the sample was 51, giving C with 50 points.

Counterpoint. Real attenuation varies with fit and product, and exposure duration and distance from speakers still matter.

Rejudgment record. Cross-check applied — We cross-checked the prespecified primary outcome, analyzed denominators, event counts, noise exposure, funding, and product supply against the JAMA report and NTR5401 record.

Scoring profile behind this grade
EndpointSSurrogate marker - laboratory or imaging measures
ReplicationR1Single confirmatory trial
IndependenceI1Mixed funding sources
Effect sizeE+Meets the clinically important threshold

The scoring table and the verdict agree (C).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Concert earplugs reduce immediate temporary hearing-threshold shift.CThe 51-person RCT found 8% versus 42%.
Concert earplugs prevent permanent hearing loss.?The identified randomized trial reported only immediate short-term measurements.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Study 1Single-blind randomized clinical trial52Support involving UMC Utrecht, MTV Benelux, Van Boxtel, and Oticon Medical; MTV Soundkeepr supplied plugs; no conflicts reportedTemporary post-exposure threshold shift at 3 and 4 kHz4/50 ears (8%) versus 22/52 ears (42%); unprotected/earplug RR 5.3 (95% CI 2.0-14.3); new tinnitus 3/25 versus 10/25Registered pivotal direct trial
§

Receipt — 2 References

Of 2 cited sources, 1 had limited original-page access (blocked or summary-only) and were verified via index/summary, marked partial; the rest were verified at the original page. As of 2026-08-14.

Ramakers GGJ, Kraaijenga VJC, Cattani G, van Zanten GA, Grolman W. Effectiveness of Earplugs in Preventing Recreational Noise-Induced Hearing Loss: A Randomized Clinical Trial. JAMA Otolaryngol Head Neck Surg. 2016;142(6):551-558. PMID: 27054284. DOI: 10.1001/jamaoto.2016.0225. NTR5401.
checked
Opperman DA, Reifman W, Schlauch RS, Levine SC. Incidence of spontaneous hearing threshold shifts during modern concert performances. Otolaryngol Head Neck Surg. 2006;134(4):667-673. DOI: 10.1016/j.otohns.2005.11.039.
partial
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-14 · Corrections: none

Cite this verdict

Concert earplugs x prevention of temporary hearing loss Evidence Grade C card
[Chamgap] Concert earplugs x prevention of temporary hearing loss — Evidence Grade C·50. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/general/concert-earplugs-temporary-threshold-shift/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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What this document does and does not do

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