Trial Outcomes & Findings for Interaural Frequency and Loudness Mismatch in SSD CI Users (NCT NCT05494632)
NCT ID: NCT05494632
Last Updated: 2025-12-26
Results Overview
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.
COMPLETED
NA
45 participants
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.
2025-12-26
Participant Flow
Recruitment occurred from July of 2022 through 2023.
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.
Participant milestones
| Measure |
Period 1: Study 1
For twenty experienced single-sided deaf (SSD) cochlear implant (CI) participants, we compared their everyday frequency allocation table (FAT) in their speech processor program to a modified FAT. The modified FAT attempted to reduce interaural frequency mismatch between the CI ear and the contralateral ear.
|
Period 2: Study 2 Group Starting With Default FAT
For 5 newly implanted SSD-CI participants, the manufacturer's default frequency allocation table (FAT) was compared to a modified FAT that attempted to reduce interaural frequency mismatch between the CI ear and the contralateral ear. Five participants were assigned the default FAT at initial activation of the device.
|
Period 2: Study 2 Group Starting With Modified FAT
For 5 newly implanted SSD-CI participants, a modified frequency allocation table (FAT) was compared to the manufacturer's default FAT. The modified FAT attempted to reduce interaural frequency mismatch between the CI ear and the contralateral ear. Five participants were assigned the modified FAT at initial activation of the device.
|
Period 3: Study 3
For fifteen participants, we compared their everyday speech processor program with a modified loudness 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.
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|---|---|---|---|---|
|
Overall Study
STARTED
|
20
|
5
|
5
|
15
|
|
Overall Study
COMPLETED
|
20
|
5
|
5
|
15
|
|
Overall Study
NOT COMPLETED
|
0
|
0
|
0
|
0
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
Interaural Frequency and Loudness Mismatch in SSD CI Users
Baseline characteristics by cohort
| Measure |
Period 1: Study 1
n=20 Participants
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.
|
Period 2: Study 2 Group Starting With Default FAT
n=5 Participants
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.
|
Period 2: Study 2 Group Starting With Modified FAT
n=5 Participants
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.
|
Period 3: Study 3
n=15 Participants
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.
|
Total
n=45 Participants
Total of all reporting groups
|
|---|---|---|---|---|---|
|
Age, Categorical
<=18 years
|
0 Participants
n=30 Participants
|
0 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=219 Participants
|
0 Participants
n=880 Participants
|
|
Age, Categorical
Between 18 and 65 years
|
13 Participants
n=30 Participants
|
4 Participants
n=30 Participants
|
5 Participants
n=60 Participants
|
7 Participants
n=219 Participants
|
29 Participants
n=880 Participants
|
|
Age, Categorical
>=65 years
|
7 Participants
n=30 Participants
|
1 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
8 Participants
n=219 Participants
|
16 Participants
n=880 Participants
|
|
Age, Continuous
|
59.2 years
STANDARD_DEVIATION 10.8 • n=30 Participants
|
49.6 years
STANDARD_DEVIATION 13.0 • n=30 Participants
|
56.8 years
STANDARD_DEVIATION 12.6 • n=60 Participants
|
61.7 years
STANDARD_DEVIATION 10.9 • n=219 Participants
|
58.6 years
STANDARD_DEVIATION 11.6 • n=880 Participants
|
|
Sex: Female, Male
Female
|
11 Participants
n=30 Participants
|
2 Participants
n=30 Participants
|
4 Participants
n=60 Participants
|
11 Participants
n=219 Participants
|
28 Participants
n=880 Participants
|
|
Sex: Female, Male
Male
|
9 Participants
n=30 Participants
|
3 Participants
n=30 Participants
|
1 Participants
n=60 Participants
|
4 Participants
n=219 Participants
|
17 Participants
n=880 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=30 Participants
|
0 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=219 Participants
|
0 Participants
n=880 Participants
|
|
Race (NIH/OMB)
Asian
|
0 Participants
n=30 Participants
|
0 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=219 Participants
|
0 Participants
n=880 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=30 Participants
|
1 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=219 Participants
|
1 Participants
n=880 Participants
|
|
Race (NIH/OMB)
Black or African American
|
0 Participants
n=30 Participants
|
1 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
1 Participants
n=219 Participants
|
2 Participants
n=880 Participants
|
|
Race (NIH/OMB)
White
|
20 Participants
n=30 Participants
|
3 Participants
n=30 Participants
|
5 Participants
n=60 Participants
|
14 Participants
n=219 Participants
|
42 Participants
n=880 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=30 Participants
|
0 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=219 Participants
|
0 Participants
n=880 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=30 Participants
|
0 Participants
n=30 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=219 Participants
|
0 Participants
n=880 Participants
|
PRIMARY outcome
Timeframe: 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.
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.
Outcome measures
| Measure |
Period 1: Study 1
n=20 Participants
Twenty experienced single-sided deaf cochlear implant recipients (SSD-CI) compared their everyday speech processor program frequency allocation table (FAT) to a modified FAT. The modified FAT was created to reduce interaural frequency mismatch between the normal hearing ear and the cochlear implant ear. Participants were first tested with their everyday FAT. They were tested a second time after 6 weeks use of the modified FAT. Lastly, they compared both FATs on their speech processor at home for several weeks, after which they were tested a second time with each FAT.
|
Period 2: Study 2 Group starting with default FAT
n=5 Participants
Five newly implanted single-sided deaf cochlear implant recipients (SSD-CI) participated. They compared the manufacturer's default FAT to a modified FAT. The modified FAT was created to reduce interaural frequency mismatch between the normal hearing ear and the cochlear implant ear. Five participants were assigned the manufacturer's default FAT at initial activation. After 6 weeks use of the default FAT, participants were tested and then began using the modified FAT for another 6 weeks. Participants were tested with the modified FAT at the end of six weeks. Then, participants compared FATs on their speech processor for several weeks and were tested with each FAT a second time.
|
Period 2: Study 2 Group starting with Modified FAT
n=5 Participants
Five newly implanted single-sided deaf cochlear implant recipients (SSD-CI) participated. They compared a modified FAT to the manufacturer's default FAT. The modified FAT was created to reduce interaural frequency mismatch between the normal hearing ear and the cochlear implant ear. Five participants were assigned the modified FAT at initial activation. After 6 weeks use of the modified FAT, participants were tested and then began using the default FAT for another 6 weeks. Participants were tested with the default FAT at the end of six weeks. Then, participants compared FATs on their speech processor for several weeks and were tested with each FAT a second time.
|
Period 3: Study 3
n=15 Participants
Fifteen experienced SSD-CI recipients compared their everyday speech processor program to a modified loudness speech processor program. The modified loudness program was created in an attempt to balance loudness between the normal hearing ear and the cochlear implant ear and therefore decrease interaural loudness mismatch. Participants were first tested with their everyday program. They were tested a second time after 6 weeks use of the modified program. Lastly, they compared both programs on their speech processor at home for several weeks, after which they were tested a second time with each program.
|
|---|---|---|---|---|
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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
|
-1.9 signal-noise-ratio in decibels (dB)
Standard Deviation 1.9
|
-4.0 signal-noise-ratio in decibels (dB)
Standard Deviation 0.7
|
-2.9 signal-noise-ratio in decibels (dB)
Standard Deviation 1.1
|
|
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
|
-2.9 signal-noise-ratio in decibels (dB)
Standard Deviation 2.5
|
-3.6 signal-noise-ratio in decibels (dB)
Standard Deviation 1.0
|
-4.1 signal-noise-ratio in decibels (dB)
Standard Deviation 1.0
|
Adverse Events
Period 1: Study 1
Period 2: Study 2
Period 3: Study 3
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Jill B Firszt, PhD
Washington University School of Medicine
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place