The study aims to phenotype hearing in patients with early stage of neurodegenerative disorders to explore the prevalence of various hearing disorders in comparison to a control population. Specific focus is made on patients with speech-in-noise intelligibiltiy deficit despite normal tonal audiograms referred to as hidden hearing loss, with potential identification of associated biomarkers.

A wide battery of subjective and objective hearing tests is performed on the subjects including tonal and vocal audiometry (in silence and in noise), DPOAE, acoustic reflex and electrophysiology recordings (auditory brainstem response, electrocochleography). Hearing tests are correlated to collected disease parameters and blood markers.

Inclusion Criteria: All subjects

1. Man or woman aged between 50 and 85 years old at baseline.
2. Fluent in French (native language)
3. Be considered as reliable and capable of adhering to the protocol, according to the judgment of the investigator (understanding of the information included in the protocol, and requests to realize the investigations, good general health and able to move around).
4. Affiliated to Public Health Insurance (Sécurité Sociale)
5. Signed and dated informed consent form.

For amnestic MCI:

Diagnosis of amnestic MCI, according to international diagnosis criteria (NIA-AA, 2011) with MoCA≥23 or MMSE>24.Patients must exhibit predominantly cognitive impairments in episodic memory, defined by a score on the RL/RI 16-item test with a free recall score of less than 18/48 and a total recall score of less than 40/48.

For Parkinson Patients:

Established clinical diagnosis of Parkinson's disease according to Postuma et al. 2015 with bradykinesia associated with resting tremor or rigidity, no exclusion criteria or red flag with MOCA ≥23.

For controls:

No diagnosis of neurological disease such as Parkinson's disease or MCI associated or not with Alzheimer's disease Displays normal cognitive status with a MoCA score ≥ 26.

Non-inclusion criteria:

1. Known hearing pathologies leading to conductive hearing loss (otosclerosis, a diagnosed pathology of the ear canal, tympanic membrane, ossicles or 3rd window), otitis, congenital deafness or sensorineural hearing loss associated to Menière's disease.

2. Psychiatric diseases other than neurodegenerative etiology

3. Neurological or neurovascular disorders (Stroke, epilepsy, dementia)

4. Motor complications that could interfere with audiological assessment

5. Known Diagnosis of type 2 diabetes

6. Alcohol or drug addiction

7. Cochlear implant

8. Known ototoxic drug therapy:

   1. Antibiotics: Aminosides IV, macrolides, tetracyclines in the last 15 days prior to inclusion
   2. Antipaludic drugs: quinine, hydroxychloroquine, chloroquine in the last 15 days prior to inclusion
   3. Platinum-based chemotherapy at any time prior to inclusion.
   4. Loop diuretics: furosemide (max oral dose of ≤60mg/day) at inclusion and during the study.
   5. Salicylate derivatives at high dose (Kardegic allowed at dose ≤320mg/day) at inclusion and during the study.

9. History of otological surgical act.

10. On-going pregnancy or breast-feeding.

11. Adults protected by law: in vulnerable social situations or unable to express consent.

12. Under another protocol that may interfere with the analysis of the results.

Exclusion Criteria:

Patients will be excluded from the study if one or more of the following criteria are applicable during visit 2:

1. Abnormal otoscopy as defined by less than 90% of the tympanic membrane visible (cerumen ear plug, ear drum perforation, …)
2. Conductive hearing loss defined by an air-bone threshold gap of 10 dB or greater based on the average of frequencies 0.5, 1, 2, and 4 kHz, and abnormal hearing thresholds (greater than 20 dB HL) for these frequencies.
3. Abnormal tympanogram (other type than A)
4. Asymmetric hearing loss: more than 15 dB difference in the pure-tone average (PTA) air conduction (for MCI patients and control group only)
5. Single-sided deafness (SSD)
6. Cophosis (PTAv > 120 dB)