Effects of Nonlinear Signal Processing Algorithms on Speech Perception

The purpose of this study is to investigate the effect of nonlinear signal processing algorithms on speech perception.

Study Overview

• Status: Withdrawn
• Conditions: Hearing Loss, Sensorineural; Speech; Hearing Aids
• Intervention / Treatment: Device: Tympan

Detailed Description

In this study, we are interested in how nonlinear algorithms influence speech perception.

Nonlinear algorithms are used within hearing aids and personal sound amplifiers to provide comfort to the listener. One of these algorithms provides amplification (gain) in a manner that depends on the level of the input sound.: Low-level sounds are amplified much more than high-level sounds. This type of amplification makes sounds more comfortable for listeners, but also distorts incoming sounds. To determine the effect of these algorithms on speech understanding, we will evaluate the following factors on speech perception, within the context of these algorithms:

• The input Signal-to-Noise ratio (SNR) to the algorithm (3 different SNRs)
• The type of background noise (20 people talking or 2 people talking)
• Algorithm settings (slow and fast - whether changes to gain applied to fluctuating input sounds occurs quickly or slowly)

To address our questions, we are using a wearable processor (Tympan) that allows for real-time processing of audio signals. The Tympan itself contains microphones, a processor, and small earpieces that include speakers. A listener can wear the earpieces, like headphones, and listen to sounds processed by the Tympan in real time. The Tympan allows us access to the algorithms and to the sounds processed by the algorithms so that we cannot algorithm behavior to speech perception.

Our study will complement existing work on speech perception and nonlinear algorithms, but our study will be the first to use a wearable processor in which the specific algorithm is known, tailored to an individual's hearing levels, and which allows for direct calculation of the output SNR. Most studies also have not measured speech perception, and this will be one of only a handful of studies with that objective.

• Study Type: Interventional
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Indiana
    • Bloomington, Indiana, United States, 47408
      • Health Sciences Building

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Between the ages of 18 and 65
• Native speaker of English
• Have bilateral, symmetric sensorineural hearing loss that is less than 75 decibels (dB) Hearing Level (HL) at 1000 Hz and below.

Exclusion Criteria:

• Subjects with normal hearing, mixed hearing loss, or asymmetric sensorineural hearing loss.
• Subjects who younger than 18 or older than 65.
• Subjects who are not native speakers of English.
• Subjects with thresholds more than 70 dB HL at 2000 Hz and below

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• 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: Perceptual measures; Perception will be measured for different algorithm settings and environmental variables (type of noise and signal-to-noise ratio)	Device: Tympan; Participants will wear a prototype hearing aid (called the Tympan)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Speech understanding	Percent words correct will be measured	1-2 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Preference	Algorithm preference will be measured for each experimental condition	15 minutes

Collaborators and Investigators

• Sponsor: Indiana University

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2023
• Primary Completion (Actual): June 9, 2025
• Study Completion (Actual): June 9, 2025

Study Registration Dates

• First Submitted: July 13, 2023
• First Submitted That Met QC Criteria: July 13, 2023
• First Posted (Actual): July 20, 2023

Study Record Updates

• Last Update Posted (Actual): June 12, 2025
• Last Update Submitted That Met QC Criteria: June 9, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: speech perception, hearing aids
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Ear Diseases; Hearing Disorders; Hearing Loss; Hearing Loss, Sensorineural
• Other Study ID Numbers: 18675

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

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