Older adults show significantly lower cochlear gain estimates than younger adults

Evidence

Estimates of cochlear gain were calculated as the difference in masker threshold between the 2-kHz and 1.2-kHz short maskers (Yasin et al 2014 ). Gain was determined separately for each signal level. A one-way ANOVA was conducted to compare the effect of age group on gain estimates at each signal level. There was a significant effect of age group on gain estimates at the 10-dB SL signal level [F (1,8) = 7.03, p = 0.029] and the 50-dB SPL signal level [F (1,7) = 6.86, p = 0.034]. Average amounts of gain are shown in Fig. 2 . These results suggest that gain estimates were significantly decreased in older adults compared to younger adults. Correlation coefficients were computed between auditory threshold at 2 kHz and gain estimates at both signal levels, and neither of the correlations reached statistical significance. — Dijk, Pim van, Physiology, Psychoacoustics and…, 943

Average amounts of low-side and high-side suppression for younger adults (open bars) and older adults (filled bars) at the 10-dB SL and 50-dB SPL signal levels are shown in Fig. 3 . With the short combined masker, all participants showed some low-side suppression, and all participants except for one older adult showed high-side suppression. With the long combined masker, 2/5 older adults had no measurable low-side suppression, and 3/5 older adults had no measurable high-side suppression. … This suggests that both high-side and low-side suppression estimates decreased with age. — Dijk, Pim van, Physiology, Psychoacoustics and…, 951

Estimates of cochlear gain were calculated as the difference in masker threshold between the 2-kHz and 1.2-kHz short maskers (Yasin et al 2014 ). Gain was determined separately for each signal level. A one-way ANOVA was conducted to compare the effect of age group on gain estimates at each signal level. There was a significant effect of age group on gain estimates at the 10-dB SL signal level [F (1,8) = 7.03, p = 0.029] and the 50-dB SPL signal level [F (1,7) = 6.86, p = 0.034]. — Dijk, Pim van, Physiology, Psychoacoustics and…, 940

Categorization

• XREF: This dissociation between gain reduction and audiometric threshold connects to the broader psychophysical literature (e.g., cochlear amplifier and hidden hearing loss) showing that gain changes can occur without measurable threshold shift. — connects to: Cochlear gain declines with age before measurable threshold elevation appears — Dijk, Pim van, Physiology, Psychoacoustics and…, 959; Age-linked decline in cochlear function stems from falling endocochlear potential — Dijk, Pim van, Physiology, Psychoacoustics and…, 959; Noise exposure and age produce distinct hearing-loss signatures (+1 more)
• QUESTION: The absence of a correlation between 2 kHz threshold and gain is striking — worth chasing whether age-related gain reduction reflects outer hair cell dysfunction not yet visible in audiograms.
• corroborated: 4 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 943; Dijk, Pim van, Physiology, Psychoacoustics and…, 951; Dijk, Pim van, Physiology, Psychoacoustics and…, 940

Broader Connections

• Age-linked decline in cochlear function stems from falling endocochlear potential #expands (0.78) — Dijk, Pim van, Physiology, Psychoacoustics and…, 959
• Noise exposure and age produce distinct hearing-loss signatures #complicates (0.75)
• Age-related hearing loss directly causes increased preferred treble #complicates (0.72)