Opto-electrical Cochlear Implants

NCT ID: NCT05110183

Last Updated: 2025-05-08

Basic Information

• Recruitment Status: ENROLLING_BY_INVITATION
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-04-20
• Study Completion Date: 2026-12-31

Brief Summary

Neural stimulation with photons has been proposed for a next generation of cochlear implants (CIs). The potential benefit of photonic over electrical stimulation is its spatially selective activation of small populations of spiral ganglion neurons (SGNs). Stimulating smaller neuron populations along the cochlea provides a larger number of independent channels to encode acoustic information. Hearing could therefore be restored at a higher fidelity and performance in noisy listening environments as well as music appreciation are likely to improve .

While it has been demonstrated that optical radiation evokes auditory responses in animal models, it is not clear whether the radiant exposures used in the animal experiments are sufficient to stimulate the auditory system of humans. The proposed tests are:

1. to demonstrate that light delivery systems (LDSs) can be inserted and oriented optimally in the human cochlea.

2. to show that the LDSs are able to deliver sufficient amount of energy to evoke a compound action potential of the auditory nerve.

3. to validate that the fluence rate (energy / target area) required for stimulation is below the maximal fluence rate, which damaged the cochlea in animal experiments.

4. to show that combined optical and electrical stimulation is able to significantly lower the threshold required for optical stimulation in humans.

The endpoints for the study are either the completion of the experiments proposed or the demonstration that not sufficient energy can be delivered safely in the human cochlea to develop an action potential.

Detailed Description

The patient is admitted to one of the participating clinical centers because of a brain tumor, which requires surgery to be removed. As discussed in detail with the treating surgeon, the tumor is large, and an approach will be used that accesses the tumor from the side through the temporal bone. This approach passes by the balance and hearing organ, and the partial or complete removal of the organ responsible for balance and hearing on this side is necessary. Participation in the study will extend the time of surgery by 30 minutes. There is no special preparation and no follow-up required for the study.

In this study, a cochlear implant system that uses light to stimulate the cochlea will be tested. It is a small light delivery system consisting of optical fibers and light sources the size of a human hair. This light delivery system will be inserted into the hearing organ, the cochlea before it is damaged or removed during the tumor surgery. After insertion into the cochlea, pulses of infrared light will be delivered to the cochlea, and auditory responses will be measured with a small electrode placed at the cochlea.

If possible, after completion of the measurements and during the continuation of the tumor surgery, the tissue of the hearing organ, which is typically destroyed through the drilling, will be harvested for histological evaluation.

Conditions

Hearing Loss

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: DEVICE_FEASIBILITY
• Blinding Strategy: NONE

Study Groups

electrical and optical hybrid stimulation stimulation

Patients with large tumors of the skull base, requiring a translabyrinthine craniotomy with sacrifice of their cochlea and vestibular system during the tumor resection may participate. A recording electrode will be placed on the round window, a cochleostomy will be created, and different Light delivery systems (LDSs) will be inserted into the cochlea. LDSs include angle polished optical fibers to determine the accuracy of the orientation of the radiation beam, and hybrid arrays of small optical sources and electrical contacts to evaluate electric-alone stimulation as a reference, and compare it to optic-alone and combined electrical and optical stimulation. Compound action potentials (CAPs) of the auditory nerve will be recorded.

Group Type: EXPERIMENTAL

electrical stimulation

Intervention Type: DEVICE

A cochlear implant electrode will be inserted through a cochleostomy into scala tympani of the cochlear basal turn. Custom software on a laptop computer will be used to control the delivery of a sequence of charge balanced current pules.

optical stimulation

Intervention Type: OTHER

Optical fibers will be inserted through a cochleostomy into scala tympani of the cochlear basal turn. Custom software will be used to control the delivery of a sequence of charge balanced current pules.

combined optical and electrical stimulation

Intervention Type: OTHER

A short hybrid array consisting of optical sources and electrical contacts will be inserted through a cochleostomy into scala tympani of the cochlear basal turn. Biphasic electrical current pulse and optical pulse delivery will be controlled in amplitude and timing by a computer.

Interventions

electrical stimulation

A cochlear implant electrode will be inserted through a cochleostomy into scala tympani of the cochlear basal turn. Custom software on a laptop computer will be used to control the delivery of a sequence of charge balanced current pules.

Intervention Type: DEVICE

optical stimulation

Optical fibers will be inserted through a cochleostomy into scala tympani of the cochlear basal turn. Custom software will be used to control the delivery of a sequence of charge balanced current pules.

Intervention Type: OTHER

combined optical and electrical stimulation

A short hybrid array consisting of optical sources and electrical contacts will be inserted through a cochleostomy into scala tympani of the cochlear basal turn. Biphasic electrical current pulse and optical pulse delivery will be controlled in amplitude and timing by a computer.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

Criterion for inclusion of a patient is the requirement of the translabyrinthine approach for tumor removal. The surgical approach is determined by the tumor size, the tumor location and the remaining hearing of the patient. Criteria for a translabyrinthine approach are:

1. the tumor grows in the pontine angle and the facial nerve is at risk for damage during the surgery because the tumor is already large and in close proximity of the facial nerve AND

2. the tumor is larger than 2.5 cm AND

3. Pure tone hearing thresholds are elevated by at least 50 dB AND

4. Speech discrimination scores are 50% or less

Exclusion Criteria

• adults unable to consent.
• individuals who are not yet adults (infants, children, teenagers).
• pregnant women.
• prisoners.
• vulnerable populations

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 89 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Central DuPage Hospital

OTHER

Sponsor Role: collaborator

University of Miami

OTHER

Sponsor Role: collaborator

University of Missouri-Columbia

OTHER

Sponsor Role: collaborator

National Institute on Deafness and Other Communication Disorders (NIDCD)

NIH

Sponsor Role: collaborator

Northwestern University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Claus-Peter Richter, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Northwestern University

Locations

University of Miami

Coral Gables, Florida, United States

Central DuPage Hospital Association

Winfield, Illinois, United States

University of Missouri

Columbia, Missouri, United States

Countries

United States

Other Identifiers

R01DC018666

Identifier Type: NIH

Identifier Source: secondary_id

View Link

STU00209027

Identifier Type: -

Identifier Source: org_study_id