Cochlear Implant Electrostimulation and the Influence on the Vestibular Organ

RWTH Aachen University10 enrolled

Overview

There is evidence that the sensor function of the utricle in patients with bilateral labyrinthine dysfunction (bilateral vestibulopathy) may improve balance under the influence of high frequency basal stimulation of the cochlea. The aim of the study is to measure the possible co-stimulation of the utricle (which is determined by the SVV) by tonotopic (frequency-specific) cochlear stimulation and thus to objectify whether the stimulation of the auditory nerve in CI patients also leads to an unavoidable co-stimulation of the vestibular system.

The cochlea is tonotopically structured, i.e. certain frequencies are mapped on a specific part of the cochlea from basal to apical. It is not yet known whether tonotopically differentiated stimulation of the cochlea has an unavoidable side effect on other body systems, such as the vestibular organ. If the labyrinthine dysfunction occurs as a consequence of a CI implantation, this could in the future lead to the possibility of reducing vestibular complications after CI surgery by switching certain electrodes on or off. In a first investigation phase, a conventional and already implanted CE-certified cochlear implant will be used. The aim of this project is to test certain tonotopic stimulus patterns that stimulate the cochlea by varying the volume within predefined settings. Thus, there is no misuse of the device and no change in performance attributes. Within the framework of the clinical project planned here, the testing of vestibular co-stimulation during normal cochlear stimulation via the basal, medial and apical electrodes of the CI electrode is planned. Under the influence of defined stimulation patterns, the assessment of the subjective visual vertical (SVV) in project participants will be investigated. The influence of tonotopic stimulation on the SVV result will have a high priority.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Interventions

Cochlea ImplantDEVICE

* examination and documentation of vital signs and concomitant medication * application of an cochlea implant loan processor (external body surface) with varying stimulus pattern for vestibular stimulation by means of basal, medial and apical electrodes * attraction of an special mask to determine the subjective visual vertical (SVV) * assessment of the vertical spatial axis with all electrodes turned off * assessment of the vertical spatial axis with all electrodes turned on * assessment of the vertical spatial axis while using basal (12-16) and medial (6-11) electrodes * assessment of the vertical spatial axis while using basal (12-16) and apical (1-5) electrodes * assessment of the vertical spatial axis while using medial (6-11) and apical (1-5) electrodes

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * uni- or bilaterally deafened and deaf patients with cochlear implants (one- or two- sided) from Advanced Bionics (AB), model HiRes 90K and newer * majority * given informed consent * legally competent and mentally able to follow the instructions of the personnel Exclusion Criteria: * unsuccessful CI implantation (device or electrode defects, incomplete electrode array insertion, missing neuronal stimulus responses) * pregnant and/or breastfeeding women * severe pre- or concomitant disease or reduced general ground condition, so that an outpatient presentation in the ENT polyclinic is not possible * life expectancy of less than six months * the patient has received a study medication within the last 30 days within the framework of another study * simultaneous participation in another clinical intervention study * anticipated lack of compliance * alcohol or drug abuse * the patient is placed in an institution by order of the authorities or court * patients who are in a dependent or employed relationship with the sponsor, investigator, or their deputy

Outcomes

Primary Outcomes

Change of the subjective visual vertical (SVV) with tonotopic CI stimulation

The SVV is determined by wearing a special mask that prevents patients from seeing their spatial position. Instead, they see a light bar in the mask. The head is now tilted to the left and right. After adjusting the body position, the examiner asks to be told when the light bar is perceived to be vertical.

Time frame: 15 - 30 minutes