Interaural Mismatch in SSD CI Users

Effects of Interaural Loudness and Pitch Mismatch on SSD-CI Performance

Interaural loudness and pitch mismatch in single-sided deaf cochlear implant (SSD-CI) recipients reduces binaural processing cues and contributes to performance outcomes, specifically speech understanding in noise and localization. We aim to improve binaural cues through speech processor program modifications that reduce interaural mismatches.

Study Overview

• Status: Recruiting
• Conditions: Outcomes
• Intervention / Treatment: Device: Treatment-modifications to CI speech processor program

Detailed Description

Effective binaural processing depends on similar loudness growth functions at each ear (Francart et al, 2013, Blamey et al, 2000). The use of interaural level differences (ILDs), perceived as loudness differences, to locate sound is critical given the inability of cochlear implant (CI) recipients to use interaural time differences (ITDs) in binaural processing (Francart et al, 2013, Litovsky et al, 2012). In CI recipients with single-sided deafness (SSD), perceived interaural loudness differences may not be valid indicators of interaural level differences because the CI compresses amplitude (Dorman et al, 2015). Studies suggest better preservation of ILDs may contribute to improved localization and understanding in noise. Since SSD-CI recipients use only one device, an approach to improve their use of ILDs is to match perceived loudness at each ear (Buss et al, 2018).

Binaural processing is also affected when signals of equal frequency are not matched in pitch at each ear. In bilateral CI recipients, we found that the greater the pitch mismatch between ears, the poorer the speech understanding in noise. We want to extend this work to SSD-CI recipients. Through CI program modifications, we aim to decrease the pitch and loudness mismatch between the CI ear and the normal hearing ear to improve binaural listening abilities, specifically speech understanding in noise and sound localization.

• Study Type: Interventional
• Enrollment (Anticipated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Laura K Holden, AuD; Phone Number: 314-362-7246; Email: laurakholden@wustl.edu
• Study Contact Backup: Name: Jill B Firszt, PhD; Phone Number: 314-362-4760; Email: firsztj@wustl.edu

Study Locations

• United States
  • Missouri
    • Saint Louis, Missouri, United States, 63110
      • Recruiting
      • Washington University School of Medicine
      • Principal Investigator: Jill B Firszt, PhD
      • Contact: Laura K Holden, AuD; Phone Number: 314-362-7246; Email: laurakholden@wustl.edu
      • Contact: Jill B Firszt, PhD; Phone Number: 314-362-4760; Email: firsztj@wustl.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participants for the proposed study will be adults with single-sided deafness. Participants will have at least 6 months experience with their cochlear implant or will be newly implanted with the cochlear implant.

Inclusion criteria for the experienced CI user group and the newly implant group are as follows:

• 18 years of age and older
• Postlingual onset of SSD
• Pure tone average (PTA) at 500, 1000, and 2000 Hz of less than or equal to 30 dB HL in the contralateral ear, known as the normal hearing ear
• Implanted with or chosen to be implanted with a Nucleus cochlear implant
• Full insertion of electrode array

Exclusion Criteria:

• • Not meeting the inclusion criteria

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Single arm; CI speech processor programming	Device: Treatment-modifications to CI speech processor program; We will modify the CI speech processor program to reduce interaural loudness and pitch mismatches.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Speech understanding in noise	Testing in noise will be obtained using the R-Space test which simulates listening in a noisy restaurant. The score is a signal-to-noise ratio that reflects 50% speech understanding in noise.	6 months

Collaborators and Investigators

• Sponsor: Washington University School of Medicine
• Collaborators: Cochlear
• Investigators: Principal Investigator: Jill B Firszt, PhD, Washington University School of Medicine

Study record dates

Study Major Dates

• Study Start (Actual): August 12, 2022
• Primary Completion (Anticipated): August 8, 2024
• Study Completion (Anticipated): February 8, 2025

Study Registration Dates

• First Submitted: August 8, 2022
• First Submitted That Met QC Criteria: August 8, 2022
• First Posted (Actual): August 10, 2022

Study Record Updates

• Last Update Posted (Actual): April 27, 2023
• Last Update Submitted That Met QC Criteria: April 24, 2023
• Last Verified: April 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: 202206085

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