Minimizing Facial Nerve Stimulation in Cochlear Implants

Cambridge University Hospitals NHS Foundation Trust24 enrolled

Overview

This study aims to understand how to manipulate the electrical stimulation from the cochlear implant to maximize hearing stimulation and minimize facial stimulation. It is know from animal data that the hearing and facial nerves have different sensitivities to things like electrical pulse shape, its pattern, and its duration. It is very unclear however if this applies to human cochlear implant patients, and what the optimal parameters are to selectively stimulate the hearing nerve in humans. The outcomes of this study will be used to more selectively program some patients with severe facial nerve cross stimulation and to inform the development of new types of implant stimulation.

The patients eligible for the study are deaf, and have consented as part of their standard of care to receiving a cochlear implant. There will be no interference with this process in any way. Those patients that are unfortunate to be affected by facial nerve stimulation following receiving their cochlear implant however will be contacted and with the aim to help improve their symptoms as indicated in prior animal studies

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

Conditions

Cochlear Hearing Loss Hearing Loss, Sensorineural

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Participant is willing and able to give informed consent for participation in the study. * Male or Female, aged 18 years or above. * Unilateral user of a cochlear implant or at least 6 months (post-operative group), or prospective CI user, meeting NICE criteria for implantation (intra-operative group). * First language English or sufficiently fluent in English to understand the consenting process * Post-lingual onset of severe to profound hearing loss * No other handicaps that would interfere with participation in the study in the opinion of the Principal Investigator Exclusion Criteria: * Unstable cochlear implant or hearing aid fitting * Using medication in an intermittent manner that might influence hearing levels * Cognitive or psychological challenges that might lead to variations in attention

Outcomes

Primary Outcomes

To identify stimulus parameters for cochlear implant stimulation that achieve sufficient loudness for hearing, while minimizing stimulation of the facial nerve.

The loudness level, or auditory nerve response at which facial nerve stimulation occurs for different stimulation pulse shapes will be measured for all 24 patients on both groups and help to identify different optimal stimulus parameters. By comparing the amount of electrical current required to initiate a facial nerve response for each pulse shape this will determine if there is an optimal type of stimulation to use, to reduce facial nerve stimulation.

Time frame: 18 months

Secondary Outcomes

To increase scientific understanding of the biology of the auditory and facial nerve's responses to stimulation.

This is a hugely under researched field where we are pioneering techniques and so exact outcome measures may be difficult to quantify in this scientific investigation. We are not able to use questionnaires or scientific tools at this stage, however this can be measured through electrical current measurements on the volta software for the Advanced Bionics cochlear implant company.