RP312 - Middle-Ear or Saccular Dysfunction After Cochlear Implantation?

Friday, April 21, 2023

3:15 PM – 3:45 PM PDT

Location: Rooms 608-609 ** 705 Pike

Earn 0.05 CEUs

Lead Presenter(s)

Rajesh Kumar, M.Sc. Audiology

Junior Research Fellow
All India Institute of Speech and Hearing
Mysuru, Karnataka, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

PDF Slides

Presenter(s)

PK

Prawin Kumar, PhD

Associate Professor in Audiology
AIISH
Mysore, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
KS

Kapil Sikka

All India institute of medical sciences,Delhi, Uttar Pradesh, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
NK

Nirnay Kumar Keshree

Associate Professor (Speech and Hearing), Sri Aurobindo University
Sri Aurobindo Institute of Medical Sciences
Indore, Madhya Pradesh, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
MJ

Mittali Joshi

Assistant professor
Sri Aurbindo Institute of medical sciences, indore
Indore, Madhya Pradesh, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
VM

Vishal Rattan Munjal, MS

Professor
Sri Aurobindo Medical College
Indore, Madhya Pradesh, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
DP

Digant Patni, MS

Associate professor, department of ENT
Sri Aurobindo institute of medical sciences
Indore, Madhya Pradesh, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
JK

Jithendra Kumar

Research officer
All India Institute of Speech and Hearing, Mysuru
Mysuru, Karnataka, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.
DC

Divya Chauhan

Research officer
All India institute of medical sciences,Delhi, Uttar Pradesh, India

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

Contributor (Not Presenting)(s)

Niraj Kumar Singh

All India Institute of Speech and Hearing

Financial Disclosures: I do not have any relevant financial relationships with anything to disclose.
Non-Financial Disclosures: I do not have any relevant non-financial relationships with anything to disclose.

Abstract:
Abnormal cervical vestibular-evoked myogenic potentials (cVEMP) after cochlear implantation (CI) has increasingly raised concerns about iatrogenic vestibular damage. However, the acoustic energy for evoking cVEMP travels to the saccule via the middle ear. Therefore, it is possible that despite a normal saccule the iatrogenic middle ear manipulation affects the post-implantation cVEMP. Hence, we investigated the saccular and middle ear function using cVEMP and wideband tympanometry (WBT), respectively, before and after CI. A significant association existed between the post-implantation cVEMP abnormality and the reduced absorbance, although exclusive cVEMP abnormality was also evidenced, suggesting the possibility of saccular damage in a few.

Summary:
Cochlear implantation (CI), arguably the best invention of the 20th century, is the best option to give hearing sensation to persons with hearing impairment. However, recent reports have shown undesirable post-implantation dizziness in 2-47% individuals. Several studies have also reported significantly degraded cervical vestibular-evoked myogenic potentials (cVEMP) after CI, thereby suggesting a saccular damage due to CI surgery. However, the acoustic stimuli used for generation of cVEMP, a test for saccular function, travel along the external and middle ear before stimulating the saccule. Therefore, middle ear manipulation, which is a possibility during the CI surgery, might be pivotal to the post-implantation cVEMP results. Hence, the present study aimed to compare the status of saccule using cVEMP and middle ear status using wideband tympanometry (WBT) before and after CI to understand the probable cause behind a post-implantation cVEMP abnormality. The findings presented here are from a preliminary data from an ongoing multi-centric study. Seventeen children with hearing impairment in the age range of 2-6 years, all devoid of any inner ear structural malformations, and having intact and clearly identifiable vestibulocochlear nerve on the magnetic resonance imaging, were included for the present study. Among them, 8 participants underwent uneventful cochlear implantation surgeries whereas the remaining 9 could not undergo surgery for various non-medical reasons and served as the control group. The WBT measurements were performed at peak pressure and ambient pressure conditions. Pre-stimulus rectified cVEMPs were elicited using 500 Hz tone bursts. Both, WBT and cVEMP, were administered before the CI surgery and in the week following the device switch-on. The participants in the control group underwent WBT and cVEMP using similar time lines to the CI group. Following the finding of a non-normal data distribution (p < 0.05, Shapiro-Wilk’s test), the non-parametric statistical analyses were subsequently performed. The response rate of cVEMP was 100% in the control group and in the unimplanted ears of the CI group during both evaluations. Between the two measurement points, there was no significant change in cVEMP and WBT response parameters in both ears of the control group and the unimplanted ears of the CI group. There was a significant reduction in the post-implantation response rate of cVEMP in the implanted ears (p < 0.001, Equality of test for proportions). On WBT, there was a significant post-implantation change in the wideband absorbance in the implanted ear (p < 0.05, Wilcoxon signed rank test). Further, five ears with CI had abnormal cVEMP as well as a change in absorbance, suggesting an association of cVEMP abnormality with the altered middle ear absorbance characteristics. This finding, when coupled with the knowledge that the presence of a middle ear abnormality can affect cVEMP, suggests that the absence of cVEMP after CI may be caused by the altered middle ear characteristics. However, despite the unchanged middle ear characteristics, cVEMPs were absent or reduced in amplitude after the surgery in two participants. This highlights the fact that saccular damage consequent to CI surgery is a reality, although the proportion of it appears smaller than that reported in all previous studies.

Learning Objectives:

Upon completion, the participants will be equipped to map the relationship between post-implantation changes in the middle ear and cVEMP.
Upon completion, the participants will be equipped to draw inferences about the middle ear and vestibular dysfunction after CI.
Upon completion, the participants will be able to describe the reasons for the absence of cVEMP after cochlear implantation.