Outcomes
Conditions
Brief summary
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. The study aims to improve binaural cues through speech processor program modifications that reduce interaural mismatches.
Detailed description
Effective binaural processing depends on similar loudness growth functions at each ear. 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. 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. 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. Binaural processing is also affected when signals of equal frequency are not matched in pitch at each ear. In bilateral CI recipients, the investigators found that the greater the pitch mismatch between ears, the poorer the speech understanding in noise. The investigators want to extend this work to SSD-CI recipients. Through CI program modifications, the study aims 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.
Interventions
DEVICETreatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients.
We will modify the CI speech processor program to reduce interaural frequency mismatch between the CI ear and the contralateral ear in experienced CI recipients with SSD.
DEVICETreatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients.
We will modify the CI speech processor program to reduce interaural frequency mismatch between the CI ear and the contralateral ear in newly implanted CI recipients with SSD.
DEVICETreatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.
We will modify the CI speech processor program to reduce interaural loudness mismatch between the CI ear and the contralateral ear in experienced CI recipients with SSD.
Sponsors
Washington University School of Medicine
Cochlear
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Participants were tested in the R-Space twice with each speech processor program, e.g., everyday or default program and modified program. The testing was carried out within a 2-3 month time period, and after using each program for at least 6 weeks. | Participants speech understanding was evaluated in the R-Space test environment with two speech processor programs, an everyday or default program and a modified program. The modified program was created to reduce interaural frequency or loudness mismatch between participants' CI ear and normal hearing ear. The R-Space simulates listening in a noisy restaurant, a real-world listening situation. The score is a signal-to-noise ratio that reflects 50% speech understanding in noise. Participants are surrounded by 8 loudspeakers with restaurant noise from all 8. A sentence is presented from the front loudspeaker. Participants repeat back what they hear. The noise is adjusted adaptively. For a correct response, the noise is increased; it is decreased for an incorrect response. This provides signal-to-noise ratio (SNR) for 50% speech understanding. The average score for participants with normal hearing is -5 dB SNR. A lower number represents better performance than a higher number. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORJill B Firszt, PhD
Washington University School of Medicine
Participant flow
Recruitment details
Recruitment occurred from July of 2022 through 2023.
Pre-assignment details
In Study 2, 5 participants used the default FAT for 6 weeks, then used the modified FAT for 6 weeks. 5 other participants used the modified FAT for 6 weeks, then the default FAT for 6 weeks. This was done to prevent order effects. Finally, all participants compared both FATs for 2 weeks. All 10 participants were tested twice with each FAT.
Participants by arm
| Arm | Count |
|---|---|
| Period 1: Study 1 For 20 participants, we compared their everyday frequency allocation table (FAT) in their CI speech processor program to a modified FAT. The modified FAT was created to reduce the interaural frequency mismatch between the CI ear and the contralateral ear of experienced CI recipients with single sided deafness (SSD). Participants were tested twice with each FAT over about an 8-10 week period. Speech recognition in noise was the primary result analyzed. | 20 |
| Period 2: Study 2 Group Starting With Default FAT For 5 newly implanted participants, we compared the manufacturer's default frequency allocation table (FAT) in their CI speech processor program to a modified FAT. The modified FAT was created to reduce the interaural frequency mismatch between the CI ear and the contralateral ear of newly implanted CI recipients with single sided deafness (SSD). Five participants were assigned the default FAT at initial activation of the device. Participants were tested twice with each FAT over about a 16 week period. Speech recognition in noise was the primary result. | 5 |
| Period 2: Study 2 Group Starting With Modified FAT For 5 newly implanted participants, we compared a modified FAT to the manufacturer's default FAT in their CI speech processor program. The modified FAT was created to reduce the interaural frequency mismatch between the CI ear and the contralateral ear of newly implanted CI recipients with single sided deafness (SSD). Five participants were assigned the modified FAT at initial activation of the device. Participants were tested twice with each FAT over about a 16 week period. Speech recognition in noise was the primary result. | 5 |
| Period 3: Study 3 For 15 participants, we compared their everyday speech processor program to a modified speech processor program. The modified program was created to reduce the interaural loudness mismatch between the CI ear and the normal hearing ear in these experienced CI recipients with SSD. Participants were tested twice with each program, i.e., their everyday program and the modified loudness program over about an 8-10 week period. Speech recognition in noise was the primary result. | 15 |
| Total | 45 |
Baseline characteristics
| Characteristic | Total | Period 1: Study 1 | Period 2: Study 2 Group Starting With Default FAT | Period 2: Study 2 Group Starting With Modified FAT | Period 3: Study 3 |
|---|---|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 16 Participants | 7 Participants | 1 Participants | 0 Participants | 8 Participants |
| Age, Categorical Between 18 and 65 years | 29 Participants | 13 Participants | 4 Participants | 5 Participants | 7 Participants |
| Age, Continuous | 58.6 years STANDARD_DEVIATION 11.6 | 59.2 years STANDARD_DEVIATION 10.8 | 49.6 years STANDARD_DEVIATION 13 | 56.8 years STANDARD_DEVIATION 12.6 | 61.7 years STANDARD_DEVIATION 10.9 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 2 Participants | 0 Participants | 1 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 1 Participants | 0 Participants | 1 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 42 Participants | 20 Participants | 3 Participants | 5 Participants | 14 Participants |
| Sex: Female, Male Female | 28 Participants | 11 Participants | 2 Participants | 4 Participants | 11 Participants |
| Sex: Female, Male Male | 17 Participants | 9 Participants | 3 Participants | 1 Participants | 4 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 20 | 0 / 10 | 0 / 15 |
| other Total, other adverse events | 0 / 20 | 0 / 10 | 0 / 15 |
| serious Total, serious adverse events | 0 / 20 | 0 / 10 | 0 / 15 |
Outcome results
Primary
Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant.
Participants speech understanding was evaluated in the R-Space test environment with two speech processor programs, an everyday or default program and a modified program. The modified program was created to reduce interaural frequency or loudness mismatch between participants' CI ear and normal hearing ear. The R-Space simulates listening in a noisy restaurant, a real-world listening situation. The score is a signal-to-noise ratio that reflects 50% speech understanding in noise. Participants are surrounded by 8 loudspeakers with restaurant noise from all 8. A sentence is presented from the front loudspeaker. Participants repeat back what they hear. The noise is adjusted adaptively. For a correct response, the noise is increased; it is decreased for an incorrect response. This provides signal-to-noise ratio (SNR) for 50% speech understanding. The average score for participants with normal hearing is -5 dB SNR. A lower number represents better performance than a higher number.
Time frame: Participants were tested in the R-Space twice with each speech processor program, e.g., everyday or default program and modified program. The testing was carried out within a 2-3 month time period, and after using each program for at least 6 weeks.
Population: 20 experienced SSD-CI participants were tested in the R-Space with their everyday use FAT and with the modified FAT (Study 1). Ten newly implanted SSD-CI participated in Study 2. The newly implanted group were tested in the R-Space with the manufacturer's default FAT and with a modified FAT. Fifteen experienced SSD-CI users were tested in the R-SPACE with their everyday program and with a modified loudness program (Study 3). Testing was done twice with each FAT or loudness program.
| Arm | Measure | Group | Value (MEDIAN) | Dispersion |
|---|---|---|---|---|
| Period 1: Study 1 | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Everyday FAT (study 1), Default FAT (study 2), Everyday loudness program (study 3) | -3.0 signal-noise-ratio in decibels (dB) | Standard Deviation 1.6 |
| Period 1: Study 1 | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Modified FAT (study 1 and 2), Modified loudness program (study 3) | -3.6 signal-noise-ratio in decibels (dB) | Standard Deviation 1.1 |
| Period 2: Study 2 Group starting with default FAT | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Modified FAT (study 1 and 2), Modified loudness program (study 3) | -2.9 signal-noise-ratio in decibels (dB) | Standard Deviation 2.5 |
| Period 2: Study 2 Group starting with default FAT | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Everyday FAT (study 1), Default FAT (study 2), Everyday loudness program (study 3) | -1.9 signal-noise-ratio in decibels (dB) | Standard Deviation 1.9 |
| Period 2: Study 2 Group starting with Modified FAT | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Everyday FAT (study 1), Default FAT (study 2), Everyday loudness program (study 3) | -4.0 signal-noise-ratio in decibels (dB) | Standard Deviation 0.7 |
| Period 2: Study 2 Group starting with Modified FAT | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Modified FAT (study 1 and 2), Modified loudness program (study 3) | -3.6 signal-noise-ratio in decibels (dB) | Standard Deviation 1 |
| Period 3: Study 3 | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Everyday FAT (study 1), Default FAT (study 2), Everyday loudness program (study 3) | -2.9 signal-noise-ratio in decibels (dB) | Standard Deviation 1.1 |
| Period 3: Study 3 | Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. | Modified FAT (study 1 and 2), Modified loudness program (study 3) | -4.1 signal-noise-ratio in decibels (dB) | Standard Deviation 1 |
p-value: <0.001Wilcoxon (Mann-Whitney)