Speech Locator In-car Performance Evaluation
Phase: NA
Conditions: Hearing Loss
Sponsor: Sonova AG

 
 
 
 
Study Protocol and Statistical Analysis Plan 
 
Speech Locator In-car Performance Evaluation– ID# SRF-459 
Jan 27, 2022 
 
NCT05054816 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Speech Locator In-car Performance Evaluation– ID# SRF-459 
1 Objectives and hypotheses of the clinical investigation 
1.1 Purpose of the clinical investigation claims for clinical performance, 
effectiveness or safety of the investigational device that are to be verified 
The insight on general and individual preferences between the investigational feature and comparator 
features will be used to determine if and when the investigational feature should be included in an 
upcoming platform release. The initial clinical evaluation of the development of this feature has been 
requested by Research & Development.  
1.2 Primary and Secondary Objectives  
The primary objective of this study is to measure the subjective impression of the investigational feature 
(using overall impression and listening effort ratings) in 20 experienced hearing aid users with mild to 
severe hearing loss. 
The second objective is to determine if there are any audible artifacts while implementing the feature, 
and if there are, measure how bothersome they are to the listener.  
2 Design of the clinical investigation 
2.1 General 
2.1.1 Design Type 
This is a randomized, double-blinded in-person study with participants serving as self-controls.  
2.1.2 Measures for minimizing bias 
Bias will be minimized by (1) randomizing stimuli presentation and (2) double-blinding of stimuli through 
automated playback.  
2.1.3 Endpoints with rationale for their selection and measurement 
Ratings are expected to be different among different test conditions. An internal evaluation has been 
completed with normal hearing employees, who reported audible differences for all selected sound 
dimensions. Rationales for the specific rating dimensions are as the following: 
Speech clarity ratings: Participants will be instructed to “Please rate the clarity of speech”. Speech 
clarity ratings will be measured on a 100-point continuous slider from worst to best (0-Very unclear, 25-
Unclear, 50-Slightly clear, 75-Clear, 100-Very clear). Speech clarity ratings are expected to be impacted 
by how intelligible the speech is. Participants will rate and compare speech clarity between the 
investigational and comparator features.  
Noise annoyance ratings: Participants will be instructed to “Please rate how annoying the noise is”. 
Noise annoyance ratings will be measured on a 100-point continuous slider from worst to best (0-
Extremely annoying, 25-Very annoying, 50-Moderately annoying, 75-Slightly annoying, 100-Not at all 
annoying). Noise annoyance ratings are expected to be impacted by how bothersome the background 

noise in the recordings is. Participants will rate and compare noise annoyance between the 
investigational and comparator features. 
Spatialization ratings: Participants will be instructed to “Please rate your confidence that the talker is in 
[a location]”, with the local being either passenger of rear left. Spatialization ratings will be measured on 
a 100-point continuous slider from worst to best (0-I don’t know where the talker is, 25-The talker might 
be to my [location], 50-The talker is probably to my [location], 75-The talker is to my [location], 100-The 
talker is definitely to my [location]). Spatialization ratings are expected to be impacted by how well the 
recordings preserve spatial perception. Participants will rate and compare spatialization between the 
investigational and comparator features. 
Overall impression ratings: Participants will be instructed to “All things considered, please rate overall 
preferences”. Overall preferences ratings will be measured on a 100-point continuous slider from worst 
to best (0-Bad, 25-Poor, 50-Fair, 75-Good, 100-Excellent). Overall impression ratings are expected to be 
impacted by participants’ overall preferences for the different stimuli. Participants will rate and compare 
overall impression between the investigational and comparator features. 
Transition annoyance ratings: Participants will be instructed to “Please rate how annoying the 
transitions are”. Transitions annoyance ratings will be measured on a 100-point continuous slider from 
worst to best (0-Extremely annoying, 25-Very annoying, 50-Moderately annoying, 75-Slightly annoying, 
100-Not at all annoying). Transition annoyance ratings are expected to be influenced by presence of 
unexpected sounds or transitions that occur in different microphone modes and different listening 
situations. Participants will rate and compare transition annoyance between the investigational and 
comparator features. 
 
2.2 Procedures 
2.2.1 Investigation-related Procedure  
Participant eligibility is determined based on case history on file. The case history consists of 
audiograms, etiology of hearing loss, other medical information, and personal details like age, gender, 
contact information, occupation, hobbies, etc. Case history information is gathered prior to the study 
and as a part of database management, which is a separate process from this investigation. 
Participants will be screened for the study using an outreach email and/or call. After successful 
completion of screening, participants will sign the consent form and complete the demographic 
questionnaire upon arrival for their first session.  
2.2.2 Sponsor activities 
Study sponsor is responsible for participant recruitment, assessment, data collection, analysis and 
monitoring. 
2.2.3 Outcome comprising factors 
Participants need to meet the hearing loss criteria in order to judge the differences in the recordings for 
the targeted hearing loss group. If participants cannot tolerate the loudness of the output, they could 
miss these differences. Therefore, we will recruit only experienced hearing aid wearers.  

Participants need to be tech-savvy to the extent that they are comfortable operating the subjective HPP 
tool using a touchscreen interface, keyboard and/or mice. We will ask for their ability to do so during 
the screening call. If problems arise during the study session and support cannot solve the issue, the 
participant will be withdrawn from the study.  
Subjective ratings often are not as sensitive as objective outcome measures because participants need 
to pay attention to small differences. The sound samples have been selected with regards to 
representation of scenes in which the hearing aid processing produces audible differences. Questions 
will be formulated in a way that draws participants’ attention to the anticipated area of focus (i.e. 
speech, talker location, microphone mode) 
3 Statistical design and analysis 
3.1 Determination of Sample Size 
We will recruit up to 25 participants, including up to 5 pilot participants. Previous research with 
subjective ratings has repeatedly shown that data collected with 15-25 participants can yield significant 
results. 
3.2 Statistical criteria of termination of trial 
If the results are significant after 15 participants have completing the protocol, we will consider 
terminating the data collection.  
3.3 Planned Analyses 
The statistical analysis plan includes the methods and types of the analysis, the variables the data sets 
and the timeframe when the (interim) analysis is planned. Recall that participants will be completing 
three repetitions of each stimulus. Repetitions will be averaged within each participant prior to analysis. 
Reliability within each participant will also be assessed to determine if that participant’s data should be 
included the analysis.  
• 
Repeated-measures analysis of variance (RM-ANOVA) to detect significant effects 
• 
Post-hoc pairwise comparisons to locate the source of significant effects 
3.3.1 Datasets to be analyzed, analysis population 
• 
Analysis population: 15-25 participants 
• 
Evaluation group: 
rating per setting 
• 
Data sets:  
 
subjective ratings 
• 
Additional analyses: 
o Individual preferences and their potential dependences, such as hearing loss,  
3.3.2 Primary Analysis 
The study manager will analyze the collected data set in R Statistics after the data collection is 
completed. Microsoft Excel and MATLAB may be used for arranging data and plotting data sets. 
3.3.3 Secondary Analysis 
The study manager will analyze the collected data set in R Statistics after the data collection completed.  

3.3.4 Interim Analysis 
The study manager will analyze the collected data set in R Statistics in real time as the data collection is 
completed. Microsoft Excel and MATLAB may be used for arranging data and plotting data sets. 
4 Informed consent process 
4.1 Process for obtaining informed consent  
Participants are required to sign a consent form prior to participation in the study. The consent form will 
be provided at the time of their first appointment and relevant tick boxes for this particular study will be 
noted. Participants will consent by writing their names and signature and will include the name of the 
researcher obtaining consent. The document will  be converted into a PDF and will be uploaded into the 
database. The paper form will be stored in a secured cabinet only accessible by the researchers.