Toward a Differential Diagnosis of Hidden Hearing Loss in Humans.
Level 4 - case-series / case-control
Cross-sectional comparative study (graded by design analogy)
PubMed 27618300 · doi:10.1371/journal.pone.0162726
What was done
College students were classified into low-risk and high-risk groups based on self-reported history of noise exposure and hearing protection use. Investigators assessed cochlear function using otoacoustic emissions and click-evoked electrocochleography (measuring the ratio of the Summating Potential to Action Potential, or SP/AP ratio). Auditory performance was evaluated using standard behavioral audiometry, extended high-frequency audiometry (10–16 kHz), and word recognition tests under conditions with or without noise, time compression, and reverberation.
What was found
The abstract reports directions of effect without specific numerical values or exact sample sizes. Both groups maintained normal thresholds at standard audiometric frequencies. The high-risk noise exposure group demonstrated significant threshold elevations at extended high frequencies (10–16 kHz), a significant difference in the electrocochleographic SP/AP ratio reflecting selective neural loss, significantly poorer performance on word recognition in complex listening environments (noise, time compression, and reverberation), and heightened self-reported sound sensitivity consistent with hyperacusis.
Why it matters
The findings provide human translational support for animal models of cochlear synaptopathy, demonstrating that noise-induced neural damage and speech-in-noise deficits can occur even when standard clinical audiograms appear completely normal.
Limits
The abstract provides no exact sample sizes, confidence intervals, or numerical data. Noise exposure history was determined retrospectively via self-report questionnaires, introducing recall bias. The cross-sectional design in a young college population cannot establish longitudinal causality or distinguish early permanent threshold shifts from purely isolated synaptopathy.
Cited by
- supports Individuals with hidden hearing loss show normal thresholds on standard audiograms but report difficulty hearing in noisy environments or new-onset tinnitus.