Clinical trial NCT03848338: Electrocochleography Function for Monitoring Residual Hearing
Official title: Evaluation of Intra and Post-operative Electrocochleography for the Monitoring of Residual Hearing
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Hearing Loss, Cochlear
Keywords: Cochlear Implant
Electrocochleography
Lead sponsor: Guy's and St Thomas' NHS Foundation Trust
Sponsor class: OTHER
First posted: 2019-02-20
Enrollment: 20
Sex: ALL
Minimum age (years): 1
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: OTHER

Brief summary: This trial is a pilot study to assess the feasibility of using Electrocochleography recorded from a cochlear implant intra-operatively in real time to monitor the progress of its insertion. Correlation between:

1. Observed changes in this signal during surgery and residual hearing loss post-operatively and
2. Recordings of this signal post-operatively and actual pure tone audiometry results will also be assessed.

Detailed description: Cochlear Implants (CIs) can provide deaf individuals the ability to hear. CIs are electronics packages inserted into the cochlea (hearing organ). An external processor digitises sound and transmits it to the implant. An electric stimulus from the implant mimics the change in electrical potential normally caused by the movement of stereocilia in the cochlea when a sound occurs. This change generates an impulse along the auditory nerve to the brain resulting in perception of sound.

CIs are available in the UK to people who have profound hearing loss. The improvement of CI technology means individuals with less significant losses, or profound losses at only some pitches may now benefit from a CI over a hearing aid. Patients having useful residual hearing has led to interest in better preserving that hearing during surgery. Thus allowing benefit from traditional acoustic amplification in addition to electrical stimulation from the implant.

The investigators propose recording a measurement via the implant during surgery and at audiology appointments called a cochlear microphonic using a technique called electrocochleography (ECochG). This is essentially recording the electrical signal generated by the movement of hair cells in the cochlea in response to a sound. It is hypothesised that reduction of this signal during implantation may correspond to cochlea damage occurring and that with development this signal might be useful feedback for surgeons. The signal is known to be correlated to actual hearing ability so a better understanding of this may allow us to fit the acoustic amplification portion of implants in individuals who are unable to respond reliably to a normal hearing test.

The purpose of this study is a pilot to assess the correlation between observed changes in this signal during surgery and residual hearing loss post-operatively and the degree correlation between recordings of this signal post-operatively and actual hearing test results.

Eligibility criteria: Inclusion Criteria:

* Meets normal candidacy requirements for cochlear implantation
* At least 1 year of age at time of consent being given
* Patent cochlea as verified by CT or MRI scan
* No cochlear abnormality that might prevent insertion of the electrode array
* Measurable residual hearing in the ear to be implanted
* No additional complex needs that would prevent study procedures or normal clinical follow-up protocol being followed
* AB Implant selected by patient or MDT
* Written informed consent obtained

Exclusion Criteria:

* Medically complex cases where minimal duration of surgery is required

Primary outcomes:
measure: Cochlear Microphonic Amplitude (micro volts) via Electrocochleography during Cochlear Implant Insertion
timeFrame: 1 Year
measure: Cochlear Microphonic Amplitude (micro volts) via Electrocochleography during post-operative audiological appointments
timeFrame: 1 Year
Secondary outcomes:
measure: ECochG Correlations
timeFrame: 1 Year
Other outcomes:
Locations:
city: London
country: United Kingdom
facility: Hearing Implant Centre, Guy's and St Thomas' NHS Foundation Trust
Study officials:
affiliation: Head of Audiology and Consultant Clinical Scientist
name: Terry B Nunn, MSc
role: PRINCIPAL_INVESTIGATOR
affiliation: Professor of Otology and Auditory Implantation Surgery.
name: Dan Jiang, PhD FRCS
role: STUDY_CHAIR
References:
citation: Dalbert A, Pfiffner F, Hoesli M, Koka K, Veraguth D, Roosli C, Huber A. Assessment of Cochlear Function during Cochlear Implantation by Extra- and Intracochlear Electrocochleography. Front Neurosci. 2018 Jan 26;12:18. doi: 10.3389/fnins.2018.00018. eCollection 2018.
citation: Pienkowski M, Adunka OF, Lichtenhan JT. Editorial: New Advances in Electrocochleography for Clinical and Basic Investigation. Front Neurosci. 2018 May 8;12:310. doi: 10.3389/fnins.2018.00310. eCollection 2018. No abstract available.
citation: Koka K, Saoji AA, Litvak LM. Electrocochleography in Cochlear Implant Recipients With Residual Hearing: Comparison With Audiometric Thresholds. Ear Hear. 2017 May/Jun;38(3):e161-e167. doi: 10.1097/AUD.0000000000000385.
citation: O'Connell BP, Holder JT, Dwyer RT, Gifford RH, Noble JH, Bennett ML, Rivas A, Wanna GB, Haynes DS, Labadie RF. Intra- and Postoperative Electrocochleography May Be Predictive of Final Electrode Position and Postoperative Hearing Preservation. Front Neurosci. 2017 May 29;11:291. doi: 10.3389/fnins.2017.00291. eCollection 2017.
citation: Mandala M, Colletti L, Tonoli G, Colletti V. Electrocochleography during cochlear implantation for hearing preservation. Otolaryngol Head Neck Surg. 2012 May;146(5):774-81. doi: 10.1177/0194599811435895. Epub 2012 Jan 30.
citation: Soulby A, Connor S, Jiang D, Nunn T, Boyle P, Pai I. Establishing Reproducibility and Correlation of Cochlear Microphonic Amplitude to Implant Electrode Position Using Intraoperative Electrocochleography and Postoperative Cone Beam Computed Tomography. Ear Hear. 2021 Sep/Oct;42(5):1263-1275. doi: 10.1097/AUD.0000000000001010.