Encoding Temporal Fine Structure for Cochlear Implants (TFS4CIs)

November 20, 2023 updated by: Raymond Goldsworthy, University of Southern California
The goal of this study is to improve music and speech perception for cochlear implant users. Presently, most cochlear implants discard the temporal fine structure of sound, which is information that is widely believed to contribute to both music and speech perception. The proposed work examines perceptual and physiological changes that occur once this information is provided to cochlear implant users in a clear and consistent manner.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The study goal is to improve music and speech perception for cochlear implant users. The relevant health outcome is their quality of life. This proposal focuses on how well cochlear implant users can learn to use temporal fine structure if provided as a clear and consistent cue for music or voice pitch. Historically, cochlear implants have discarded temporal fine structure and have only transmitted timing information of relatively slow envelope fluctuations. Attempts have been made to restore temporal fine structure into cochlear implant stimulation, but it is unclear whether previous attempts were limited by implementation, lack of experience, or inherently by physiology. The proposed approach is unique in that it examines the perceptual and physiological plasticity that occurs when temporal fine structure is restored. Proposed research is organized into two aims, which examine the relative salience of stimulation place and rate for providing a sense of pitch (Aim 1) and the salience of dynamic-rate stimulation compared to conventional methods (Aim 2). Both aims combine perceptual learning, computer-controlled electrode psychophysics, electrophysiology, and computational neural modeling to characterize the plasticity of pitch perception in cochlear implant users.

Aim 1 examines the perceptual and physiological plasticity associated with place and rate of cochlear implant stimulation. Cochlear implant users hear an increasing pitch associated with increasing stimulation rate, but this effect is difficult to measure above 300 Hz. Most studies of psychophysical sensitivity to cochlear implant stimulation rate have not considered perceptual learning. Preliminary results show that the sense of pitch provided by stimulation rate improves with training. The proposed research examines perceptual sensitivity and physiological encoding throughout a crossover training study with training provided for pitch based on place and rate of stimulation. The primary hypothesis tested is that cochlear implant users have a latent ability to hear pitch associated with stimulation rate, but they require training to learn how to use this new information.

Aim 2 is to determine whether dynamic-rate stimulation provides better sensitivity and better physiological encoding of fundamental frequency compared to conventional stimulation methods based on amplitude modulation of constant-rate stimulation. In normal physiology, auditory-nerve activity phase locks to the temporal fine structure of sound. Since cochlear implants typically discard this information, it is unknown how well cochlear implant users can learn to use it if provided. Aim 2 focuses on the comparison between dynamic-rate stimulation in which stimulation rate is dynamically adjusted to convey temporal fine structure compared to conventional methods based on amplitude modulation of constant-rate stimulation. The primary hypothesis is that dynamic-rate stimulation provides better pitch sensitivity and better physiological encoding compared to amplitude modulation of constant-rate stimulation.

Study Type

Interventional

Enrollment (Estimated)

24

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Cochlear implant users.

Exclusion Criteria:

  • Younger than 18 years.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Stimulation Rate
Behavioral: Stimulation Rate
Psychophysical training listening to stimulation rate as a cue for auditory pitch perception. The intervention is the listening rehabilitative exercises. Exercises are completed daily as 30-minute sessions for 2 weeks.
Behavioral: Electrode Location
Psychophysical training listening to electrode location as a cue for auditory pitch perception. The intervention is the listening rehabilitative exercises. Exercises are completed daily as 30-minute sessions for 2 weeks.
Active Comparator: Electrode Location
Behavioral: Stimulation Rate
Psychophysical training listening to stimulation rate as a cue for auditory pitch perception. The intervention is the listening rehabilitative exercises. Exercises are completed daily as 30-minute sessions for 2 weeks.
Behavioral: Electrode Location
Psychophysical training listening to electrode location as a cue for auditory pitch perception. The intervention is the listening rehabilitative exercises. Exercises are completed daily as 30-minute sessions for 2 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Baseline electrode psychophysics prior to training.
Time Frame: Measure collected prior to training.
Just-noticeable difference for pitch ranking based on stimulation cues. Pitch discrimination will be measured as provided independently by place and rate of cochlear implant stimulation, as well as in combination. Stimuli will be dual-electrode pulse trains, which probe place-pitch perception with greater resolution than possible with single-electrode stimulation. Two-alternative forced-choice procedures will be used in which participants judge which of two stimuli is higher in pitch. Frequency discrimination will be measured near condition frequencies of 110, 220, 440, 880, and 1760 Hz for each of the 4 stimulation conditions (place, rate, combined). Adaptive procedures will be used to measure 75% discrimination accuracy.
Measure collected prior to training.
Midpoint electrode psychophysics.
Time Frame: Measure collected at 4-week midpoint during psychophysical training.
Just-noticeable difference for pitch ranking based on stimulation cues. Pitch discrimination will be measured as provided independently by place and rate of cochlear implant stimulation, as well as in combination. Stimuli will be dual-electrode pulse trains, which probe place-pitch perception with greater resolution than possible with single-electrode stimulation. Two-alternative forced-choice procedures will be used in which participants judge which of two stimuli is higher in pitch. Frequency discrimination will be measured near condition frequencies of 110, 220, 440, 880, and 1760 Hz for each of the 4 stimulation conditions (place, rate, combined). Adaptive procedures will be used to measure 75% discrimination accuracy.
Measure collected at 4-week midpoint during psychophysical training.
Endpoint electrode psychophysics.
Time Frame: Measure collected at 8-week endpoint following psychophysical training.
Just-noticeable difference for pitch ranking based on stimulation cues. Pitch discrimination will be measured as provided independently by place and rate of cochlear implant stimulation, as well as in combination. Stimuli will be dual-electrode pulse trains, which probe place-pitch perception with greater resolution than possible with single-electrode stimulation. Two-alternative forced-choice procedures will be used in which participants judge which of two stimuli is higher in pitch. Frequency discrimination will be measured near condition frequencies of 110, 220, 440, 880, and 1760 Hz for each of the 4 stimulation conditions (place, rate, combined). Adaptive procedures will be used to measure 75% discrimination accuracy.
Measure collected at 8-week endpoint following psychophysical training.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Southern California

Collaborators

Ohio State University
University of Rochester

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 1, 2020

Primary Completion (Estimated)

September 1, 2024

Study Completion (Estimated)

December 5, 2024

Study Registration Dates

First Submitted

January 7, 2021

First Submitted That Met QC Criteria

January 11, 2021

First Posted (Actual)

January 14, 2021

Study Record Updates

Last Update Posted (Estimated)

November 21, 2023

Last Update Submitted That Met QC Criteria

November 20, 2023

Last Verified

November 1, 2023

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R01DC018044 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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