Basic and Clinical Studies of Cochlear Synaptopathy
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.
⁃ 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.