Study of the Role of Top-down Processes in Neuronal Reorganization and Recovery From Sensory Loss: an Exploratory Behavioral and Electroencephalographic Study in Cochlear-supported Deaf Patients (REASCENT)

This study posits that central top-down processes (attention, inhibition), marked by alpha oscillations in EEG, play a key role. Understanding the evolution of these neuronal signatures and their link to pre-implantation visual dependence could allow the identification of biomarkers predictive of the success of auditory rehabilitation.

Study Overview

• Status: Not yet recruiting
• Conditions: Deafness, Bilateral
• Intervention / Treatment: Other: neurophysiological assessment; Behavioral: Cognitive, behavioral and quality of life assessment

Detailed Description

Profound bilateral deafness leads to sensory deprivation and neuronal reorganization ( visual recruitment of the auditory cortex). Although cochlear implants restore hearing, comprehension performance varies considerably. Peripheral factors explain only 40% of this variance. This study posits that central top-down processes (attention, inhibition), marked by alpha oscillations in EEG, play a key role. Understanding the evolution of these neuronal signatures and their link to pre-implantation visual dependence could allow the identification of biomarkers predictive of the success of auditory rehabilitation.

• Study Type: Observational
• Enrollment (Estimated): 90

Contacts and Locations

• Study Contact: Name: Mathieu MARX, Pr; Phone Number: 05 61 77 77 04; Email: marx.m@chu-toulouse.fr
• Study Contact Backup: Name: Florine LEGAY; Phone Number: +33 5 61 77 82 04; Email: legay.f@chu-toulouse.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Participants with cochlear implants will be informed about this study during a routine check-up at the partner hearing aid laboratory (Audial), or by the ENT department at Purpan Hospital during a consultation as part of patient follow-up. All participants with normal hearing (young and old) will be recruited through announcements made to members of the ENT department and the CerCo UMR 5549 laboratory.

Description

Inclusion Criteria:

For cochlear implant patients:

• Adult patients
• Profound bilateral hearing loss requiring a first cochlear implant
• Normal cochlear anatomy (confirmed by preoperative imaging)
• Full insertion of the cochlear electrode array planned
• Acceptance of the protocol and signing of the informed consent form
• Enrollment in a social security or equivalent plan

For young patients with normal hearing:

• Adult patients aged 18 to 40
• Normal and symmetrical hearing
• Acceptance of the protocol and signature of the informed consent form
• Affiliation with a social security scheme or equivalent

For older patients with normal hearing:

• Patients over 50 years of age, matched by gender and age (+/- 2 years) with the cochlear implant patient group
• Normal and symmetrical hearing, with hearing thresholds < 20 dB HL at 2 kHz and < 40 dB HL at 4 kHz
• Acceptance of the protocol and signature of the informed consent form
• Affiliation with a social security scheme or equivalent

For experienced cochlear implant recipients:

• Adult patients.
• Unilateral cochlear implant activated for 1 year or more.
• Disyllabic word recognition score at 60 dB in free field of 70% or higher.
• Acceptance of the protocol and signature of the informed consent form.
• Affiliation with a social security plan or equivalent.

For severely deaf patients fitted with hearing aids:

• Adult patients.
• Severe bilateral hearing loss.
• Rehabilitation with one or two optimally fitted hearing aids.
• Acceptance of the protocol and signing of the informed consent form.
• Enrollment in a social security or equivalent health insurance plan.

Exclusion Criteria:

• History of associated neurological pathology
• Etiologies with unfavorable prognoses, such as recurrent chronic otitis media: These conditions are associated with a poor prognosis due to chronic inflammation that can affect the cochlea
• Duration of profound bilateral deafness exceeding 5 years (worse prognosis)
• Contraindications to EEG or other neurophysiological examinations within the study (for all groups)
• Cognitive impairment confirmed by the MOCA test for the cochlear implant patient group and the group of elderly subjects with normal hearing
• Use of psychotropic medications that may interfere with the results of cognitive or neurological tests
• History of epilepsy or other major neurological disorders
• Pregnancy or breastfeeding
• Participation in another interventional research protocol or one that impacts the criteria studied in this project
• Individuals under legal guardianship (guardianship, tutorship, curatorship, institutionalized, or under a future protection mandate)

Study Plan

How is the study designed?

Number of groups / cohorts

5

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Group of cochlear implant patients; This group consists of adult patients with profound bilateral hearing loss, candidates for a first unilateral cochlear implant, and meeting the specific inclusion criteria.	Other: neurophysiological assessment; Electroencephalography and eye tracking; Behavioral: Cognitive, behavioral and quality of life assessment; Cognitive anfd behavioral assessment : Speech recognition test in silence (MBAA) and in noise, verbal working memory task with distractors, Trail Making Test and MoCA test. Quality of lige assessment : This questionnaire is a set of scales concerning patients' hearing abilities, experience, and listening skills in different situations. For each question, the patient must answer by choosing a number between 1 (not at all) and 10 (perfectly).
Group of young, normally hearing subjects; This control group consists of healthy young adult subjects (18-40 years old) with normal and symmetrical hearing confirmed by audiometry.	Other: neurophysiological assessment; Electroencephalography and eye tracking; Behavioral: Cognitive, behavioral and quality of life assessment; Cognitive anfd behavioral assessment : Speech recognition test in silence (MBAA) and in noise, verbal working memory task with distractors, Trail Making Test and MoCA test. Quality of lige assessment : This questionnaire is a set of scales concerning patients' hearing abilities, experience, and listening skills in different situations. For each question, the patient must answer by choosing a number between 1 (not at all) and 10 (perfectly).
Group of normally hearing elderly subjects matched for gender and age; This control group consists of healthy older adults (> 50 years) with age-appropriate hearing (thresholds defined in the inclusion criteria) confirmed by audiometry. They are matched by age (+/- 2 years) and gender with the cochlear implant patient group.	Other: neurophysiological assessment; Electroencephalography and eye tracking; Behavioral: Cognitive, behavioral and quality of life assessment; Cognitive anfd behavioral assessment : Speech recognition test in silence (MBAA) and in noise, verbal working memory task with distractors, Trail Making Test and MoCA test. Quality of lige assessment : This questionnaire is a set of scales concerning patients' hearing abilities, experience, and listening skills in different situations. For each question, the patient must answer by choosing a number between 1 (not at all) and 10 (perfectly).
Group of experienced cochlear implant patients; This control group consists of adult patients using a unilateral cochlear implant for at least one year and exhibiting good hearing performance (≥70% word recognition).	Other: neurophysiological assessment; Electroencephalography and eye tracking; Behavioral: Cognitive, behavioral and quality of life assessment; Cognitive anfd behavioral assessment : Speech recognition test in silence (MBAA) and in noise, verbal working memory task with distractors, Trail Making Test and MoCA test. Quality of lige assessment : This questionnaire is a set of scales concerning patients' hearing abilities, experience, and listening skills in different situations. For each question, the patient must answer by choosing a number between 1 (not at all) and 10 (perfectly).
Group of hearing-equipped deaf patients; This control group consists of adult patients with severe bilateral deafness who have been rehabilitated with optimally fitted hearing aids.	Other: neurophysiological assessment; Electroencephalography and eye tracking; Behavioral: Cognitive, behavioral and quality of life assessment; Cognitive anfd behavioral assessment : Speech recognition test in silence (MBAA) and in noise, verbal working memory task with distractors, Trail Making Test and MoCA test. Quality of lige assessment : This questionnaire is a set of scales concerning patients' hearing abilities, experience, and listening skills in different situations. For each question, the patient must answer by choosing a number between 1 (not at all) and 10 (perfectly).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evolution of oscillatory signatures	Composite criterion :the modulation of alpha oscillations, measured through frequency analysis, amplitude variations and temporal synchronization via EEG, in response to a word recognition task in silence.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
EEG (alpha) signatures and eye-tracking	Descriptive evaluation : Evolution of EEG (alpha) signatures and eye-tracking trajectories (composite criterion)	6 months
Speech recognition performance	Speech recognition performance (MBAA, accuracy, response time) in silence and noise : Composite criterion	6 months
alpha modulation and memory/auditory	Correlations between alpha modulation and memory/auditory performance : Descriptive evaluation	6 months
audiovisual, visual and auditory comparison	The comparison between audiovisual, visual and auditory modalitie (descriptive evaluation)	6 months
SSQ	This questionnaire is a set of scales concerning patients' hearing abilities, experience, and listening skills in different situations. For each question, the patient must answer by choosing a number between 1 (not at all) and 10 (perfectly).	6 months

Collaborators and Investigators

• Sponsor: University Hospital, Toulouse
• Collaborators: Centre de recherche Cerveau et Cognition (CERCO)
• Investigators: Principal Investigator: Mathieu MARX, PU-PH, University Hospital, Toulouse

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): March 1, 2029
• Study Completion (Estimated): March 1, 2029

Study Registration Dates

• First Submitted: March 24, 2026
• First Submitted That Met QC Criteria: March 24, 2026
• First Posted (Actual): March 30, 2026

Study Record Updates

• Last Update Posted (Actual): March 30, 2026
• Last Update Submitted That Met QC Criteria: March 24, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: cochlear implant; deaf; electroencephalographic; top-down processes; sensory loss
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Ear Diseases; Hearing Loss; Hearing Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hearing Loss, Bilateral
• Other Study ID Numbers: RC31/26/0005; 2026-A00163-48 (Other Identifier: ANSM)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No