Evaluating Benefits of Hearing Aid Microphone Directionality Technologies on Spatial Awareness and Speech Intelligibility
Phase: NA
Conditions: Hearing Loss
Sponsor: Sonova AG

Study Protocol and Statistical Analysis Plan 
 
 
Evaluating Benefits of Hearing Aid 
Microphone Directionality Technologies 
 
 
 
V.2 
May 24, 2022 
 
 
 
 
NCT04953390 
 
 
 

 
 
 
Protocol Title 
Evaluating Benefits of Hearing Aid Microphone Directionality 
Technology 
 
1 Background 
Paradise hearing instruments (HI) have an adaptive binaural beamformer, known as 
Stereozoom (SZ) that is activated in speech in loud noise (SiLN) environments. SZ has been 
proven to provide speech intelligibility (SI) benefits to HI users in noise. In particular, SZ has 
shown up to a 5.5 dB improvement over an omnidirectional microphone and up to 1.5 dB 
improvement over Phonak's monaural beamformer, Ultrazoom (UZ), in speech reception 
threshold (SRT) assessments in noise. A summary of these findings can be found in the 
"Phonak Compendium Stereozoom Part I: the benefit of wirelessly connected narrow 
directionality in Phonak hearing aids for speech intelligibility" by Stewart et. al (2019) 
available on phonakpro.com. SZ achieves these speech intelligibility benefits through mixing 
the input of each hearing instrument (HI) to create a narrow beam with a variable null that 
adapts in accordance to the noise source(s).  
 
The effect of this mixing is a narrow beamformer with a high directivity index (DI) that is ideal 
for listening to single, front-facing speech sources. However, the mixing of HI inputs also 
results in the loss of spatial perception.  
In comparison, the monaural beamformer, Ultrazoom (UZ), does not mix the HI inputs 
between sides. As such, it retains localization cues and; therefore, creates a spatial release 
from masking.  
Accordingly, there is a tradeoff between Stereozoom and Ultrazoom, wherein SZ provides 
better directivity and UZ provides better spatial awareness. Good directivity and spatial 
awareness both contribute to improved speech intelligibility, so it is problematic to have to 
choose between one or the other.  
Therefore, there is an opportunity to balance the advantages of both to optimize the 
performance of the binaural beamformer. This might be achieved through a change in the 
binaural beamformer strength. Today, in Paradise devices, the beamformer strength of SZ 
can be thought of as 70%. As such, the opportunity to change the beamformer strength could 
mean making the beamformer wider (<70%) or narrower (>70%), and both should be 
explored. In addition to the binaural beamformer strength, it would also be worthwhile to 
investigate the transition speed for binaural beamformer activation. The current transition 
speed for SZ is instantaneous (time constant = 0 sec.), which may be disturbing for some 
users. Elongating the transition time may result in a more pleasant user experience.  
 
StereoZoom 2.0 is a new parameterization that balances the tradeoff between UZ and SZ. It 
has not yet been evaluated on human subjects. An evaluation of this feature with human 
subjects may identify which beamformer strength and transition speed settings strike the best 
balance between good directivity and spatial awareness while maintaining a pleasant user 
experience.  

2 Objectives 
The primary objective is to investigate the effect of binaural beamformer strength on spatial 
perception in speech in noise (SiN) environments through a subjective spatial awareness 
task comparing three beamformer strengths, including Stereozoom (SZ), with experienced 
hearing aid users with moderate hearing loss. 
List of the secondary objectives:  
a. The secondary objective is to investigate the effect of binaural beamformer strength on 
speech intelligibility in noise through an objective SRT task comparing three beamformer 
strengths, including SZ, with experienced hearing aid users with moderate hearing loss.  
b. The secondary objective is to investigate the perceived benefit(s) of user steering of the 
binaural beamformer strength for SIN with experienced hearing aid users with moderate 
hearing loss.  
c. The secondary objective is to investigate the perceived benefit(s) of longer transition time 
(> 0 sec) for activation of the binaural beamformer through a comparison of multiple 
transition times with one beamformer strength, with experienced hearing aid users with 
moderate hearing loss.  
 
3 Description of the investigational device 
This clinical investigation is intended to further development of the StereoZoom 2.0 feature. 
This feature will be available in future iterations of the Phonak Audeo hearing devices The 
overall intended purpose of the device is to amplify and transmit sound to the ear and hereby 
compensate for impaired hearing. 
4 Design of the clinical investigation 
This interventional study will have 2-3 conditions per task for a sample population of 15-20 
human subjects. The order of conditions will be counterbalanced and the participants will be 
blinded to the conditions. 
5 Risks and benefits of the investigational device and clinical 
Investigation 
There are minimal risks associated with both the investigational device and participating in 
the clinical investigation. The device used presents non-significant risk per FDA.  
The benefits of participating in the investigation include the benefit of personal satisfaction for 
participating in research to improve hearing instrument technology. Additionally, subjects will 
also be compensated for their time in participating in this study. 
6 Endpoints 
Primary endpoint: Subjective ratings of the beamformer strength conditions  
 
• Subjective outcome parameters: 1) Perception of beamformer strength via a 100pt scale of 
5pt increments from wide to narrow (0 = wide, 100 = narrow) and 2) Preference of 
beamformer strength via a 100pt scale of 5pt increments from not preferred to preferred (0 = 
not preferred, 100 = preferred).  
 
Secondary endpoint: Objective and subjective measures  
• Matrix Test outcome parameter: SRT 50%  

• User steering of beamformer via a slider in a mobile app outcome parameter: subjectively 
perceived benefits measured via the grouping of the beamformer setting the user chose 
alongside their response to two questions:  
1) Did you notice a change when moving the slider? (No difference, slight difference, clear 
difference) 
2) Are you satisfied with what you could achieve with the slider? (Not satisfied, somewhat 
satisfied, definitely satisfied) 
• Headphone recordings outcome parameter: Noticeability of beamformer transition in A/B 
comparisons comprised of 4 transition speeds.  
7 Inclusion and Exclusion Criteria 
Subjects fulfilling all of the following inclusion criteria are eligible for the investigation:  
• 18-90 years of age  
• Moderate to moderately severe (N3-N4) bilateral sensorineural hearing loss  
• Fluent in English; ability to read and write in English  
• Willing and able to provide informed consent  
• Participants must be experienced hearing aid users with symmetrical hearing loss defined 
as a difference of ≤ 10 dB between ears an air bone gaps ≤ 10 dB.  
• Must be able to use app and smart phone.  
The presence of any one of the following exclusion criteria will lead to the exclusion of the 
subject:  
• Self-reported ear-related pathology (otorrhea w/in 90 days, dizziness, sudden hearing loss 
or worsening of hearing w/in 90 days, otalgia)  
• Visible deformity of the ear 
• Chronic, severe tinnitus 
• Unilateral hearing loss 
• Cognitive impairment 
•Asymmetrical hearing loss 
•Other diagnoses that may cause fluctuations in hearing (i.e. Meniere’s) 
•Unable to tolerate the physical fit of a RIC device 
•Visual impairment that prevents the participant from seeing the adjustment slider in the 
mobile app 
•Inability to be seen for 3 lab visits  
8 Measurements and procedures 
 
All home-trial data is locally stored on the participant’s phone and will be manually extracted 
via a wired connection during their lab visits after each two week home trial. The extracted 
data is then saved in a company network drive.  
 
All lab data is collected digitally. There are no paper questionnaires or result sheets in this 
investigation. The data files are saved in a company network drive after task completion. 
All analysis of the results will occur at the conclusion of the study.  
9 Statistical design and analysis 
A priori sample size estimation was not performed for this investigation, as the investigation 
is exploratory and does not aim to confirm any effect with statistical significance and power. 
This is an exploratory trial and will not have statistical criteria for termination. 

Speech recognition thresholds will be recorded in dB SPL. SRT results will be recorded 
along with the anonymous participant ID, and task condition. Qualitative data will be collected 
as a question, response, and anonymous participant ID. 
Analysis of the qualitative data will take place at the conclusion of the trial. Data (raw or 
trans-formed, per above) will be subjected to analysis via linear mixed effects modeling. The 
model will be constructed to regress (raw or transformed) subjective rating on a dummy 
variable of condition (fixed effect). This model will allow the investigators to evaluate the 
relative difference in subjective ratings between the beamformer strengths. 
Analysis of the SRT data and qualitative data related to the secondary objectives will take 
place at the conclusion of the trial, using similar methodology at described above. 
10 Investigation Duration  
Expected duration of each participant’s participation is 4-5 weeks. 
 
11 Data Handling and Management 
Study data is recorded both with paper and with electronic Case Report Forms (p/eCRF). For 
each enrolled study participant a CRF is maintained. All CRFs are kept current to reflect the 
subject’s status at each phase during the course of study. Participants cannot be identified in 
the CRF by name or initials and birth date but an appropriate coded identification is used. All 
study team members are authorized for the CRF entries and it is assured that any authorized 
person can be identified both for pCRFs and eCRFs. If pCRFs are used, the investigator’s 
acronym as well as the subject ID is filled in and data are entered into an electronic file for 
analysis by the respective investigator and data get monitored by the assigned monitor. In 
case of a self-evident corrections, either the subject does it by himself or the investigator 
undertakes the correction by crossing out the word/sentence with a single horizontal line and 
by adding the correction including his personal identifier and the date. 
Source documents for this investigation include, audiograms, Target fitting files, appointment 
checklists, data packages extracted from the app, and digital results packages exported from 
software used to collect data from lab tasks. 
Any paper-based data will be stored in a locked filing cabinet at the investigation site. All 
electronic data will be stored on an access-restricted server owned, operated, and 
maintained by Sonova USA. Servers used to store data in this investigation are physically 
located in the US. Permission to access data will be limited to study manager, monitor, PI, 
and essential research staff, as designated by the principal investigator. 
During data collection of the investigation, physical copies of the data will be compiled and 
digitized by the study manager on a daily basis. Data will be reviewed for misentries or inac-
curacies as each data set is entered.  
The extent and nature of monitoring appropriate for the clinical investigation including the 
strategy for source data verification (SDV) are based on considerations such as the 
objective, design, complexity, size critical data points and endpoints of the clinical 
investigation. A de-tailed plan for monitoring arrangements is provided separately from this 
CIP. 
12 Amendments to the CIP 
If it is necessary to make an amendment to this CIP, the changes to the CIP will be clearly 
identified with the date the change was made, and the version number will be incremented. 
Non-substantial amendments (e.g., correcting a typographical error) will be recorded as a mi-

nor version incrementation, whereas substantial amendments (e.g., a change to the study 
procedure or statistical plan) will be recorded as a major version incrementation. In an emer-
gency situation, this CIP will be amended and updated only after participant health and 
safety have been assured and FDA/WIRB have been notified (as applicable). 
13 Deviations from clinical investigation plan 
Deviations from the CIP to protect the rights, safety and well-being of human participants 
under emergency circumstances may proceed without prior approval of the sponsor and the 
EC – such deviations will be documented and reported to the sponsor representative (Study 
Manager) and the EC as soon as possible. Apart from that the investigator is not allowed to 
deviate from this CIP unless that deviation does not influence the investigation data. 
14 Device accountability 
The PI or authorized designee keep records documenting the following in a written process:  
• Names of participants who received, used, returned, or disposed of device  
• Date of receipt, identification, and quantity of each investigational device (batch/serial 
number or unique code)  
 
Expiry date (if applicable)  
• Date(s) of use  
 
15 Informed consent process 
Informed consent will be obtained from participants prior to any study participation in accord-
ance with the IRB guidelines. The participants will be granted sufficient time to read through 
the consent in full and ask any questions they have before signing. After the participant signs 
the consent form, the researcher will sign and provide a copy to the participant. This process 
will take place in a private office located in the Phonak Audiology Research Center (PARC).  
Participants will be incentivized with a monetary stipend of 30 USD per hour spent at the 
investigation site, plus mileage reimbursement for round-trip travel between the investigation 
site and their home address. Mileage reimbursement will be calculated based on the shortest 
driving distance in miles multiplied by the Internal Revenue Service’s (IRS) standard mileage 
rate at the time the study concludes. 
Informed Consent will only be obtained by investigation participants who can provide 
informed consent themselves before enrollment. 
16 Adverse events, adverse device effects and device deficiencies 
Device deficiencies and all adverse events (AE) including all serious adverse events 
(SAE) are collected, fully investigated and documented in the source document and 
appropriate case report form (CRF) during the entire investigation period, i.e. from 
participant’s informed con-sent until the last protocol-specific procedure, including a safety 
follow-up period (ISO-14155, 2020). Documentation includes dates of event, treatment, 
resolution, assessment of serious-ness and causal relationship to device and/or investigation 
procedure.  
Information on AEs is systematically collected during the regular investigation visits, and 
phone calls (if applicable).  
The investigator(s) will follow-up on a biweekly basis with any participant experiencing an AE 
until either a) the participant reports resolution of the AE or b) 8 weeks have passed since 
the participant’s final visit. If, however, the participant’s condition worsens throughout the 8 

week follow-up period, the investigator will continue to follow-up biweekly until the AE is 
resolved or the participant’s condition stabilizes over an 8 week period. 
The causality assessment of the SAE will be conducted according to MDCG 2020-10/1 
Safety Reporting in Clinical Investigations of Medical Devices under Regulation (EU) 
2017/745. 
The reporting of Serious Adverse Events and Device Deficiencies follows the Regulation 
(EU) 2017/745 and the MDCG 2020-10/1 Safety Reporting in Clinical Investigations of 
Medical Devices under Regulation (EU) 2017/745. 
17 Vulnerable Populations 
This investigation will not include any vulnerable populations. 
18 Suspension or premature termination of the clinical investigation 
The study will be terminated if the majority of the participants are not able to wear the 
devices for the study visit.  
The study will be terminated if the participants or researchers are exposed to safety risks 
other than those outlined in this document.  
 
The study may be terminated in the event natural disasters, widespread outbreak of illness, 
compromised structure of the investigation site, etc. that would make continuation of the study 
impossible or impractical. The study will be suspended within 5 days of determination that the 
study or device put participants at an unreasonable risk. 
If a participant is suspended, terminated, or withdraws from the study, their data can be traced 
with their unique study identification number. 
According to the FDA, follow-up is required for participants who experience Serious Adverse 
Events. Follow up will be conducted by the study manager and/or the PI until the nature of the 
event is resolved.  
19 Publication policy 
The clinical investigation will be registered in clinicaltrials.gov, a publicly accessible 
database, as required by U.S. regulations.  
The results of the clinical investigation will be published on clinicaltrials.gov no later than one 
calendar year following the final participant appointment.  
An internal report of the results of this investigation will be completed and uploaded to 
eQMS.