Optimizing Bilateral and Single-sided-deafness Cochlear Implants for Functioning in Complex Auditory Environments

Optimizing Bilateral and Single-sided-deafness Cochlear Implants for Functioning in Complex Auditory Environments - Part 2

Cochlear implants (CIs) are devices that partially restore hearing for people with severe to profound hearing loss. This research focuses on CI users who use bilaterally implanted devices (two CIs, one on each side) and also "single-sided deafness" (SSD) CI users who use one CI together with good acoustic hearing in their opposite ear. The goal is to measure and understand the impact of large input asymmetries across the two ears. These asymmetries are common in BI-CI listeners and always present in SSD-CI users. Although most CI listeners benefit from a second source of auditory input, this project measures how these asymmetries limit speech understanding and spatial hearing. The long-term goal is countering or compensating for input asymmetries. Electrophysiological measures are used to describe the health of the auditory system. Behavioral measures are used to assess if training improves performance. CT imaging is utilized to describe the placement of the CIs.

Study Overview

• Status: Enrolling by invitation
• Conditions: Hearing Loss; Hearing Loss, Sensorineural; Cochlear Hearing Loss
• Intervention / Treatment: Diagnostic test: Diagnostic tests of cochlear implant or acoustic hearing function; Behavioral: Targeted aural rehabilitation of the poorer performing ear

• Study Type: Interventional
• Enrollment (Estimated): 300
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Bethesda, Maryland, United States, 20889
      • Walter Reed National Military Medical Center
    • College Park, Maryland, United States, 20742
      • University of Maryland, College Park

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

For Bilateral Cochlear Implant Users Arm:

Inclusion Criteria:

• two cochlear implants
• acquired their hearing loss during adulthood or late childhood (post-lingual onset)
• native English speaker
• primarily use oral language
• at least six months of cochlear implant use
• Sufficient corrected or uncorrected visual acuity (20/50 or better) to read large-font text

Exclusion Criteria:

• people who do not use oral language will be excluded.
• people with less than six months of device use will be excluded
• other known disability or neurological disorder
• women who are pregnant will be excluded from the CT portion of the study
• people with any unaided audiometric tone-detection threshold better than 60 dB HL at standard audiometric frequencies (250-8000 Hz) in either ear will be excluded

For Unilateral Cochlear Implant User with Single-Sided Deafness Arm:

Inclusion Criteria:

• one cochlear implant in one ear and a second ear with some acoustic hearing
• acquired their hearing loss during adulthood or late childhood (post-lingual onset)
• native English speaker
• primarily use oral language
• at least six months of cochlear implant use
• Sufficient corrected or uncorrected visual acuity (20/50 or better) to read large-font text

Exclusion Criteria:

• people who do not use oral language will be excluded.
• people with less than six months of device use will be excluded
• other known disability or neurological disorder
• women who are pregnant will be excluded from the CT portion of the study
• people with any unaided audiometric tone-detection threshold better than 60 dB HL at standard audiometric frequencies (250-8000 Hz) in the implanted ear will be excluded
• people with an acoustic pure-tone average threshold (octave frequencies 250-4000 Hz) > 30 dB HL in the non-implanted ear

For Non-Implanted Listeners with Acoustic Hearing Arm:

Inclusion Criteria:

• audiometrically normal hearing or near-normal hearing, or mild/moderate hearing loss
• Sufficient corrected or uncorrected visual acuity (20/50 or better) to read large-font text

Exclusion Criteria:

• severe hearing loss
• other known disability or neurological disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bilateral Cochlear Implant Users	Diagnostic test: Diagnostic tests of cochlear implant or acoustic hearing function; Because the cochlear implant participants in the study will use cochlear implant devices that they have already received as part of their standard-of-care treatment, the medical device itself is not an intervention for the purposes of this study. The intervention here will be to carry out diagnostic tests of cochlear implant or acoustic hearing function. This will include perceptual tests of sound localization, speech understanding in noise, binaural fusion, and loudness comparisons.; Behavioral: Targeted aural rehabilitation of the poorer performing ear; Subjects will undergo listening practice on a tablet computer over headphones at home. For the test group, the aural rehabilitation will be targeted at the poorer ear. For the comparison control group, a sham aural rehabilitation will present speech to both ears.
Experimental: Unilateral Cochlear Implant Users with Single-Sided Deafness	Diagnostic test: Diagnostic tests of cochlear implant or acoustic hearing function; Because the cochlear implant participants in the study will use cochlear implant devices that they have already received as part of their standard-of-care treatment, the medical device itself is not an intervention for the purposes of this study. The intervention here will be to carry out diagnostic tests of cochlear implant or acoustic hearing function. This will include perceptual tests of sound localization, speech understanding in noise, binaural fusion, and loudness comparisons.; Behavioral: Targeted aural rehabilitation of the poorer performing ear; Subjects will undergo listening practice on a tablet computer over headphones at home. For the test group, the aural rehabilitation will be targeted at the poorer ear. For the comparison control group, a sham aural rehabilitation will present speech to both ears.
Other: Non-Implanted Listeners with Acoustic Hearing	Diagnostic test: Diagnostic tests of cochlear implant or acoustic hearing function; Because the cochlear implant participants in the study will use cochlear implant devices that they have already received as part of their standard-of-care treatment, the medical device itself is not an intervention for the purposes of this study. The intervention here will be to carry out diagnostic tests of cochlear implant or acoustic hearing function. This will include perceptual tests of sound localization, speech understanding in noise, binaural fusion, and loudness comparisons.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Perceptual responses to sound level	Interaural loudness mismatch is defined as the difference between the levels required to balance interaural loudness for sequential stimulation and the levels required to perceptually center a sound image in space for simultaneous stimulation. Participants will respond through pressing virtual buttons on a computer screen. Depending on the condition tested, the sounds will be delivered to one or both ears.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. After enrollment for non-implanted listeners with acoustic hearing.
Speech understanding in the presence of masking sounds	Speech understanding will be assessed as the percentage of correctly identified keywords. Subjects will respond through oral report (where the responses will be scored by the experimenter) or through pressing virtual buttons on a computer screen. The speech sounds will be delivered to one or both ears in the presence of different types of masking sounds. In some cases, signal processing techniques will be used to distort the speech signals to simulate asymmetric hearing abilities.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. After enrollment for non-implanted listeners with acoustic hearing.
Computed-tomography scan	A computed tomography temporal bone scan will be used to image the cochlear structures and cochlear implant electrode array located within. This scan will use a standard clinical scanner, with software updated to extend the Hounsfield range to reduce artifact from the metal contacts of the electrode array. This procedure uses radiographic processes, and therefore presents the subject with a safe but nonzero amount of radiation. The CT scan will be analyzed to provide measurements of each array's insertion depth within the cochlea (in degrees and mm), the distance to the cochlear modiolus (mm), and cochlear scalar location.	For CI users: CT scan will be collected from existing medical records with permission or taken after study enrollment. Measurements taken after study enrollment. Not collected for non-implanted listeners with acoustic hearing.
Electrode impedance (transelectrode impedance matrix)	This standard clinical measurement will apply a current to one electrode, and measure the resulting induced voltage at each of the other electrodes in the array, one at a time. This process uses low-level electrical stimulation only intended to measure the impedance of the intervening tissues and fluids of the cochlea, and is rarely even perceived by the subject.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. Not collected for non-implanted listeners with acoustic hearing.
Electrically evoked compound action potentials (ECAPs)	Electrically evoked compound action potentials (ECAPs) will be measured using clinically-available software to track the growth in auditory nerve response (observed ~0.2-0.8 ms post-stimulus onset) as input level is varied from threshold to the maximal level at which the signal is comfortably loud. The slope of input-output function will be measured ( in microvolts/current unit) for each electrode along the electrode array of each cochlear implant study participant.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. Not collected for non-implanted listeners with acoustic hearing.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sound Localization	Participants' ability to localize a virtual sound source in space will be measured. Subjects will be presented with a broadband sound, with signal processing applied (temporal delays and spectral shaping) to simulate a spatial location of the sound source. Subjects will respond through pressing virtual buttons on a computer screen.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. After enrollment for non-implanted listeners with acoustic hearing.
Perceptual Fusion	Participants' ability to perceptually fuse sounds presented to the ears will be measured. Subjects will be presented with a broadband sound, and will respond through pressing virtual buttons on the computer screen as to (1) how many sounds were heard and where they were perceived inside the head, or (2) which of two mixtures presented contained a larger number of voices.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. After enrollment for non-implanted listeners with acoustic hearing.
Spectrotemporal ripple sensitivity	This test will be used to evaluate asymmetry in a perceptual measure thought to reflect the peripheral contribution to intersubject variability in speech understanding. This will allow for a baseline from which to ask if the electrophysiological measures provide additional predictive power regarding contralateral disruption beyond the perceptual measures of peripheral asymmetry.	Post-treatment - after at least 6 months use of a cochlear implant if CI user. After enrollment for non-implanted listeners with acoustic hearing.

Collaborators and Investigators

• Sponsor: University of Maryland, College Park
• Collaborators: Vanderbilt University; National Institute on Deafness and Other Communication Disorders (NIDCD); Walter Reed National Military Medical Center
• Investigators: Principal Investigator: Matthew J. Goupell, PhD, University of Maryland, College Park; Principal Investigator: Joshua G. Bernstein, PhD, Walter Reed National Military Medical Center; University of Maryland, College Park

Study record dates

Study Major Dates

• Study Start (Actual): December 19, 2023
• Primary Completion (Estimated): May 31, 2028
• Study Completion (Estimated): May 31, 2028

Study Registration Dates

• First Submitted: February 16, 2024
• First Submitted That Met QC Criteria: March 1, 2024
• First Posted (Actual): March 12, 2024

Study Record Updates

• Last Update Posted (Actual): March 28, 2025
• Last Update Submitted That Met QC Criteria: March 24, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Ear Diseases; Hearing Disorders; Hearing Loss; Deafness; Hearing Loss, Sensorineural
• Other Study ID Numbers: 2089705; 1R01DC020506-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

De-identified data that document, support, and validate research findings will be made available when the main findings have been accepted for publication. De-identified data relevant to the project will be disseminated to researchers on and off-campus by request and review of the PI.

After publication, research products from this project will be archived at the Digital Repository at the University of Maryland(DRUM). DRUM is a long-term, open access repository managed and maintained by the University of Maryland Libraries. Researchers and the general public can download data and code files, associated metadata and documentation, and any guidelines for reuse.

• IPD Sharing Time Frame: Following publication, available for at least seven years.
• IPD Sharing Access Criteria: Investigators whose proposed use of the data has been approved by an independent review committee
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No