An interventional study of electrical stimulation and optical stimulation in Hearing Loss, sponsored by Northwestern University. Enrolling by invitation at 2 sites in United States. Open to participants aged 18 Years to 89 Years. Per ClinicalTrials.gov, last updated 2026-05-06.
Sponsored by Northwestern University · Not applicable, Interventional, and Device feasibility
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:
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.
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.
1,092 studies on the registry are indexed under Hearing Loss; 235 are open to participants now.
This study's planned enrollment of 30 is below the median of 40 across 764 interventional studies indexed under Hearing Loss.
Browse Hearing Loss studies →Northwestern University is the lead sponsor of 1,396 studies on the registry; 199 are open to participants now.
Of its 102 completed or terminated interventional studies of FDA-regulated products, 73 (72%) have results posted.
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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:
Exclusion Criteria:
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.
Device: electrical stimulation · Other: optical stimulation · Other: combined optical and 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.
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.
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.
Compound Action Potential (CAP)
Compound action potentials (CAPs) of the auditory nerve in response to electrical stimulation, optical stimulation, and combined optical and electrical stimulation will be recorded. Electrical stimulation alone is used to determine baseline cochlear function. Optical stimulation alone will then be used to determine a similar baseline for optical stimulation and test parameters such as optical pulse rate, pulse duration and radiant exposure.
Time frame: 30 minutes
Plan to share: Yes — all IPD that underlie results in a publication
Supporting information: Study protocol, Sap, Icf, Csr
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