The relationship between round window and ear canal Cochlear microphonic

Yongqiang Yu; Junping Liu; Jastin Antisdel; Changming Liu; Joshua Sappington; Xiaobin Wang; Yunge Gao; Yanguo Peng; Hui Wang; Zhonghao Lin; Hongguang Ruan; Ruiying Wang; Shuwu Lin; Ming Zhang

doi:10.1002/lio2.964

The relationship between round window and ear canal Cochlear microphonic

Laryngoscope Investig Otolaryngol. 2022 Nov 25;7(6):2076-2083. doi: 10.1002/lio2.964. eCollection 2022 Dec.

Authors

Yongqiang Yu^{1

2

3

4}, Junping Liu¹, Jastin Antisdel³, Changming Liu¹, Joshua Sappington³, Xiaobin Wang⁵, Yunge Gao⁶, Yanguo Peng¹, Hui Wang¹, Zhonghao Lin¹, Hongguang Ruan¹, Ruiying Wang⁷, Shuwu Lin⁸, Ming Zhang^{4

9

10}

Affiliations

¹ Department of Otolaryngology - Head and Neck Surgery Mindong Hospital, The Affiliated Mindong Hospital of Fujian Medical University Fujian China.
² Department of Otolaryngology - Head and Neck Surgery Shandong Provincial Hospital Affiliated to Shandong First Medical University Jinan Shandong China.
³ Department of Otolaryngology - Head and Neck Surgery Saint Louis University St. Louis Missouri USA.
⁴ Department of Speech Pathology and Audiology (Communication Sciences and Disorders), Faculty of Rehabilitation Medicine University of Alberta Edmonton Alberta Canada.
⁵ Dalian Medical University Dalian China.
⁶ Strategic Support Force Medical Center Beijing China.
⁷ Department of Medicine The First Affiliated Hospital of China Medical University Shenyang China.
⁸ Department of Medicine The Second Affiliated Hospital of Shenyang Medical College Shenyang Liaoning Province China.
⁹ Department of Otolaryngology Head Neck Surgery, Faculty of Medicine University of Alberta Hospital Edmonton Alberta Canada.
¹⁰ Department of Communication Disorders Louisiana State University Health Sciences Center New Orleans New Orleans Louisiana USA.

Abstract

Hypothesis: Cochlear microphonic recorded at ear canal (CM-EC) can be a substitute for the one recorded at round window (CM-RW).

Background: Almost all clinics do not measure tone-burst evoked CM due to technical difficulty although it can provide more information than click evoked CM. Moreover, clinicians like the CM-EC more than that measured at CM-RW because CM-EC is non-invasive. There is difference between CM-RW and CM-EC, for example, CM-EC is less prominent than CM-RW, therefore, studying tone-burst evoked CM-EC and its relationship with CM-RW are highly significant and can promote the clinical application of CM-EC.

Method: Nine guinea pigs were randomly allocated into three groups, group 1 was not exposed to noise, called normal control. group 2 and group 3 were exposed to the low- (0.5-2 kHz) and high-frequency band-noise (6-8 kHz) at 120 dB SPL for 1 h, respectively. It was difficulty to record low-frequency CM due to severe environmental interruption, in current study the recording technology of tone-burst evoked CM was optimized so that tone-burst evoked CM was measured across full speech frequency (0.5-8 kHz) in the presence of normal hearing and noise induced hearing loss (NIHL).

Results: CM-RW and CM-EC were successfully recorded across speech frequency. Significant reduction in CM amplitude was observed at 0.5 and 2 kHz in group 2, at 6 and 8 kHz in group 3 as compared to group 1, p < .05, indicating that CM amplitude was sensitive to band-noise exposure. Significant correlation between CM-RW and CM-EC was also verified, p < .05.

Conclusion: CM-EC is a useful objective test for evaluation of hearing function; the result of current study supports the clinical application of non-invasive CM-EC.

Keywords: ear canal cochlear microphonic; noise induced hearing loss; round window cochlear microphonic.