Cochlear gain declines with age before measurable threshold elevation appears

Evidence

Comparing these two conditions gives an estimate of cochlear gain around the signal frequency place. It is possible that the decrease in gain for the older adults was due to their slightly poorer auditory thresholds. However, correlation coefficients between auditory threshold and gain estimates did not reach significance. This measure of gain may reflect decreases in cochlear function that occur prior to elevations in auditory thresholds. — Dijk, Pim van, Physiology, Psychoacoustics and…, 959

In Experiment 1, older adults were found to have less gain than younger adults, measured as the difference in on-frequency and off-frequency masker threshold for a fixed signal level (Yasin et al. 2014 ). The off-frequency, 1.2-kHz masker is understood to have a linear BM response at the signal frequency place, and the on-frequency, 2-kHz masker and signal have a compressive BM response at the signal frequency place (Oxenham and Plack 2000 ). Comparing these two conditions gives an estimate of cochlear gain around the signal frequency place. It is possible that the decrease in gain for the older adults was due to their slightly poorer auditory thresholds. However, correlation coefficients between auditory threshold and gain estimates did not reach significance. This measure of gain may reflect decreases in cochlear function that occur prior to elevations in auditory thresholds. Decreased endocochlear potential may have less of an effect on thresholds closer to the apex of the cochlea and a larger effect in the base (Mills et al. 2006 ) while still impacting cochlear nonlinearity. — Dijk, Pim van, Physiology, Psychoacoustics and…, 959

Categorization

• XREF: This tracks the familiar idea that cochlear damage (e.g. synaptopathy, endocochlear potential loss) can precede audiometric threshold shift — connects to hidden hearing loss literature. — connects to: Inner-ear damage accumulates silently before audiometric thresholds rise; Neural hearing damage occurs without measurable threshold elevation; Older adults show significantly lower cochlear gain estimates than younger adults — Dijk, Pim van, Physiology, Psychoacoustics and…, 943 (+4 more)
• QUESTION: If gain and suppression decline before threshold elevation, what behavioral probe could detect this early cochlear aging in a clinical setting?
• corroborated: 5 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 959

Broader Connections

• Older adults show significantly lower cochlear gain estimates than younger adults #corroborates (0.92) — Dijk, Pim van, Physiology, Psychoacoustics and…, 943
• Age-related hearing decline in noise begins while thresholds remain normal #corroborates (0.90) — Dijk, Pim van, Physiology, Psychoacoustics and…, 1140
• Age-linked decline in cochlear function stems from falling endocochlear potential #expands (0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 959
• Hearing sensitivity degrades with age and is lower in early childhood #qualifies (0.72)