Fundamental and Clinical Study of Cochlear Synaptopathy

NCT06556160 | Completed

• 1 other identifier: PO23045
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

Brief Summary

In humans, surface electrophysiological recording of the cochlear nerve in response to a sound stimulus provides information about the integrity and function of synapses (synaptic transmission) and nerve fibre function. However, this information remains global. The investigators have preliminary data showing that it is possible to extract and characterise the functional properties of nerve fibres during otoneurosurgery in humans, and therefore to isolate the neuronal sub-populations mentioned above more precisely than is currently possible. The use of these electrophysiological data from near-field recordings, i.e. in contact with the nerve, will enable the design and improvement of a mathematical model of the human cochlea. This model will provide access to the individual responses of each nerve fibre and fill the current gap in knowledge between the functioning of these fibres and global surface recordings.

Conditions

Hearing Loss

Keywords

Hearing Loss; Deafness; Micro vascular decompression; otoneurosurgery; retrosigmoid approach

Outcome Measures

Primary Outcomes (2)

• In response to a stimulus, the neurophonic potential recorded in the form of a wave called PSTR will be characterised patients defined as normo and hearing loss based on preoperative audiometric tests

  During ponto cerebellum retro sigmoide surgery. In response to a stimulus, the neurophonic potential recorded in the form of a wave called PSTR will be characterised patients defined as normo and hearing loss based on preoperative audiometric tests by the following indices:- the amplitude of the peak- the amplitude of the plateau- the peak to plateau ratio- the time constant for the rapid decay of the peak- the time constant for the slow decay of the peak.

  At 48 months

• Compare the amplitude and spectrum of global evoked auditory nerve activity with basic stimuli between patients defined as normo and hearing loss based on preoperative audiometric tests

  During ponto cerebellum retro sigmoide surgeryelectrocochleography and distortion products.

  At 48 months

Secondary Outcomes (1)

• compare the primary objective with the results obtained with a mathematical model of the human cochlea in order to improve the responses of our model.

  At 48 months

Study Arms (2)

hearing impaired patients

EXPERIMENTAL

have a sensorineural hearing loss defined by hearing thresholds of 20 dB HL or better from 0.25 to 2 kHz and from 20 dB HL excluded to 55 dB HL at frequencies above 2 kHz.

Procedure: near field recording of human auditory nerve activity during retro sigmoid approach with contact electrode

normal hearing patients

ACTIVE COMPARATOR

free of neuro-sensory deafness, defined by mean hearing thresholds of less than or equal to 20 dB HL in pure tone audiometry in air conduction bilaterally on the side of the ear operated on and on the non-operated side from 0.25 to 8 kHz

Procedure: near field recording of human auditory nerve activity during retro sigmoid approach with contact electrode

Interventions

near field recording of human auditory nerve activity during retro sigmoid approach with contact electrode PROCEDURE

During surgery using a retro-sigmoid approach in the cerebellopontine angle (microvascular decompression), near-field recording of human auditory nerve activity using a contact electrode is performed on patients with normal or impaired hearing threshold. Each patient is explored preoperatively by hearing tests to search synaptopathie. During the surgery, stimuli are delivered.

hearing impaired patients; normal hearing patients

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients with normal hearing will be included:
• male or female
• over 18 and up to 70 years of age
• normal otoscopic examination
• due to undergo surgery on the cerebellopontine angle (microvascular decompression).
• free of neuro-sensory deafness, defined by mean hearing thresholds of less than or equal to 20 dB HL in pure tone audiometry in air conduction bilaterally on the side of the ear operated on and on the non-operated side from 0.25 to 8 kHz
• affiliated to a social security scheme
• have read the information note describing the study and have agreed in writing to take part by signing the informed consent form.
• Patients with a hearing impairment will be included:
• male or female
• over 18 and up to 70 years of age
• normal otoscopic examination
• due to undergo surgery on the cerebellopontine angle (microvascular decompression).
• have a sensorineural hearing loss defined by hearing thresholds of 20 dB HL or better from 0.25 to 2 kHz and from 20 dB HL excluded to 55 dB HL at frequencies above 2 kHz.
• have read the information note describing the study and have agreed in writing to take part by signing the informed consent form.

You may not qualify if:

• \- Patients will be excluded from the study for whom the auditory nerve is not accessible during surgery, in particular because of complete tumour invasion of the cochlear nerve (stage III and IV neuroma, advanced meningioma) or because of a particular anatomical feature not identified during the preoperative examination, making it impossible to expose the nerve for recordings (protrusion of the posterior surface of the rock).

Sponsors & Collaborators

• CHU de Reims: lead

Study Sites (1)

Damien JOLLY

Reims, France

Location

MeSH Terms

Conditions

Hearing Loss; Deafness

Condition Hierarchy (Ancestors)

Hearing Disorders; Ear Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 17, 2023
• First Posted: August 15, 2024
• Study Start: March 21, 2023
• Primary Completion: July 16, 2025
• Study Completion: November 4, 2025
• Last Updated: December 18, 2025

Record last verified: 2025-12

Locations

FR (1)