A Study to Evaluate the Safety and Performance of a Vestibular Implant in Adults to Provide Balance Restoration

Inclusion Criteria:

• Adults of 18 years or older with bilateral vestibulopathy >1 year of evolutionwithout benefit from conventional rehabilitation treatment. Symptoms unlikely toimprove according to clinicians´ estimation.

• Hearing impairment ranging from:

1. Early feasibility stage (first 6 subjects enrolled): moderate to severe hearingloss with PTA of 41-70 dB HL on the ear to be implanted.

2. Late feasibility stage (12 subjects): normal hearing to severe hearing losswith PTA ≤ 70 dB HL on the ear to be implanted.

• Patients diagnosed with bilateral vestibulopathy or probable bilateralvestibulopathy based on the consensus document of the Barany Society on vestibularimplant candidate criteria for research [van de Berg et al., 2020]: a. Unsteadiness when walking or standing plus at least one of the following: i.Movement-induced blurred vision or ii. Oscillopsia during walking or quick head/bodymovements, and/or iii. Worsening of unsteadiness in darkness and/or on uneven groundb. Symptoms greatest during head movement and not compensated after rehabilitationprogram. c. Bilaterally reduced or absent angular VOR function documented by atleast one of the following major criteria: i. Pathological horizontal angular VORgain ≤ 0.6 and at least one vertical angular VOR gain < 0.7, measured by thevideo-HIT technique. ii. Reduced caloric response (sum of bithermal max. peak SPV oneach side ≤6◦/sec for 30 sec water stimuli or <10◦/sec for 60 sec of air stimuli).In case only one of two criteria from c. are matched, the remaining test(s) shouldcomply with the following minor criteria: 1) Bilaterally pathological VOR gains ofat least two semicircular canals < 0.7, measured by the video- HIT or scleral-coiltechnique 2) Reduced caloric response (sum of bithermal max. peak SPV on each side <10°/sec for water and air stimuli of ≥30 sec). d. Absent cVEMP and oVEMP responsesin the ear to be implanted.

• Anatomical optimal conditions for implantation evaluated by CT and MRI:

vestibule permeability ascertained and present intact vestibular nerve.

• Ability to use the device and follow a personalized rehabilitation program.

• Ability to undergo the surgery.

Exclusion Criteria:

• Dynamic Gait Index > 18 and Functional Gait Assessment > 22

• Ossification or other inner ear anomalies that prevent full insertion of electrodes.

• Middle ear disorders including conductive hearing loss.

• Retro cochlear or central origins of hearing impairment.

• Medical contraindications for surgery.

• Chronic depression, dementia and cognitive disorders that could, at the discretionof the clinician, significantly interfere with use or evaluation of the VI.

• Cerebellar ataxias without bilateral vestibulopathy and CANVAS.

• Known genetical indication for ataxia.

• Known diagnosis of DFNA9.

• Downbeat nystagmus syndrome.

• Persistent Postural-Perceptual Dizziness.

• Vestibular suppressant medications.

• Oculomotor disorders (if oscillopsia is prominent).

• Peripheral neuropathies.

• Central gait disorders due to normal pressure hydrocephalus, frontal gait disorders,subcortical vascular encephalopathy or multiple sclerosis.

• Intoxications (i.e. excessive alcohol and/or drugs use).

• No current psychological or psychiatric disorder that could significantly interferewith use or evaluation of the VI.

• Unable or unwilling to comply with the requirements of the clinical investigation asdetermined by the Investigator.

• Unrealistic expectations on the part of the subject, regarding the possiblebenefits, risks and limitations that are inherent in the procedure and prostheticdevice.

• Investigator site personnel directly affiliated with this study and/or theirimmediate families; immediate family is defined as a spouse, parent, child, orsibling.

• Cochlear employees or employees of Contract Research Organizations or contractorsengaged by Cochlear for the purposes of this investigation.

• Pregnant or breastfeeding women.

• Current participation, or participation in another interventional clinicalstudy/trial in the past 30 days, involving an investigational drug or device (unlessdetermined by the investigator or Sponsor to not impact this investigation).