AUTHOR=Wang Yao , Li Xiao , Ren Fuxin , Liu Siqi , Ma Wen , Zhang Yue , Qi Zhihang , Yang Jing , Li Honghao , Fu Xinxing , Wang Huiquan , Gao Fei 

TITLE=High-Frequency Cochlear Amplifier Dysfunction: A Dominating Contribution to the Cognitive-Ear Link

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 13 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2021.767570

DOI=10.3389/fnagi.2021.767570

ISSN=1663-4365

ABSTRACT=Objective
To investigate the role of high-frequency cochlear dysfunction in the cognitive-ear link. 
Methods
Seventy-four presbycusis patients (PC group) and seventy-one age-, sex- and education-level matched normal hearing controls (NH group) were recruited in this study. Participants underwent a battery of cognitive tests estimated by Montreal Cognitive Assessment (MoCA), Stroop Color-Word Interference Test (Stroop), Symbol Digit Modalities Test (SDMT), Auditory Verbal Learning Test (AVLT), and Trail-Making Test (TMT-A and B), as well as auditory tests including distortion product otoacoustic emission (DPOAE), pure tone thresholds, and speech reception thresholds (SRT). Data were analyzed using factor analysis, partial correlation analysis, multiple linear regression models, and mediation models.
Results
DPOAE detection amplitudes and pure tone thresholds performed worse gradually from low to high frequencies in both the NH and PC groups. High-frequency DPOAE (H-DPOAE) was significantly correlated with cognitive domains in the PC group (AVLT: r = 0.30, p = .04; SDMT: r = 0.36, p = .01; Stroop: r = -0.32, p = .03; TMT_A: r = -0.40, p = .005; TMT_B: r = -0.34, p = .02). Multiple linear regression models showed that H-DPOAE predicted cognitive impairment effectively for aspects of memory (R2 = 0.27, 95% CI, 0.03 to 1.55), attention (R2 = 0.32, 95% CI, -6.18 to -0.40, processing speed (R2 = 0.37, 95% CI, 0.20 to 1.64), and executive function (TMT-A: R2 = 0.34, 95% CI, -5.52 to 1.03; TMT-B: R2 = 0.29, 95% CI, -11.30 to -1.12). H-DPOAE directly affected cognition and fully mediated the relationship between PTA/SRT and cognitive test scores, excluding MoCA.
Conclusions
This study has demonstrated that high-frequency cochlear amplifier dysfunction has a direct predictive effect on cognitive decline and makes a large contribution to the cognitive-ear link.