Correlation between pure tone audiometry at all frequencies and distortion product otoacoustic emission of patients with hidden hearing loss

To explore the correlation between pure tone audiometry at all frequencies and distortion product otoacoustic emission (DPOAE) of hidden hearing loss (HHL). The workers exposed to noise from a factory in Zhangjiakou (noise exposure group, n = 73) and normal young and middle-aged people recruited by society (control group, n = 77) from August 2021 to April 2022 were study subjects, and all of them underwent audiometry in clinic. Compared with the control group, the noise exposure group had significantly higher threshold by extended high-frequency audiometry at all frequencies and higher signal-to-noise ratio threshold (SNR50) (all P < 0.001), and higher amplitude ratio of SP to AP of the waveform induced by short sound at 96, 90, 80 and 70 dB nHL and lower SNR at 6 kHz and above (all P < 0.05). The pure tone audiometry was correlated with DPOAE test results at the frequencies of 6, 8, 9 and 10 kHz (P < 0.001). The results of speech audiometry in noise were related to the average SNR of DPOAE test at each frequency (P = 0.026,r = -0.265). The ratio of SP to AP in electrocochleogram recorded at the intensity of 96 dB nHL was correlated with the average SNR at 6 kHz and above in DPOAE test (P = 0.018,r = -0.461), and with the average auditory threshold at each frequency in extended high-frequency audiometry (P = 0.032, r = 0.421). DPOAE has certain value in detecting HHL.