Preliminary Study 1 to Test the Effects of Ambulatory Voice Biofeedback in Small Groups of Patients With Vocal Hyperfunction
Phase: NA
Conditions: Vocal Fold Nodules
Sponsor: Massachusetts General Hospital

Official Title: Preliminary Studies to Test the Effects of Ambulatory Voice Biofeedback 
NCT Number: 03416829 
Date: June 16th, 2022 
 
Study Protocol: 
Study One will assess if AVB paradigms can effect short- and long-term changes in vocal loudness 
behavior in a small group of patients with vocal hyperfunction (VH). More specifically, it will determine 
which of three types of ambulatory feedback results in better learning/retention (100% frequency, 
25% frequency, or delayed summary feedback every 2 minutes of voicing) of a new vocal behavior 
(reduced vocal loudness) in three groups of 15 patients with vocal fold nodules. It is hypothesized that 
patients receiving lower frequency or summary feedback will produce lower initial performance but 
higher short- and long-term retention than patients receiving feedback 100% of the time. 
 Inclusion/Exclusion criteria for the patients are summarized below: 
Inclusion Criteria 
Exclusion Criteria 
Age: 18 – 65 years 
Previous monitoring: Patients must have 
successfully completed approximately 1 
week of baseline voice monitoring in 
protocol 2011P002376 
 
For Study 1 only: 
Diagnosis: vocal fold nodules 
Non-English Speaker 
 
Unable to answer questions and/or 
follow instructions 
 
Patients with a sensitivity to hypo 
allergenic adhesive 
 
Pregnant women 
 
Study One will include 54 total patients with phonotraumatic VH (45 patients + potential 20% dropout 
rate) and will be recruited from the Massachusetts General Hospital (MGH) Voice Center. The 
procedures and design for Study One are essentially identical to a previously approved IRB protocol 
(# 2014001870) which used normal subjects [37]. The proposed study seeks to replicate the previous 
results in patients with VH in order to move toward the clinical implementation of this approach. Each 
subject will be assigned (via block randomization) to three groups with different AVB schedules: 1) 
100% immediate biofeedback (vibrotactile cueing every time the participant exceeds a vocal intensity 
threshold), 2) 25% immediate biofeedback (vibrotactile cueing every 4th time the participant exceeds 
a vocal intensity threshold), and 3) delayed summary biofeedback (no cueing; summary statistics 
shown every 2 minutes of voiced time). Patients with phonotraumatic VH have been chosen since 
reducing vocal loudness is often a goal of therapy.  
 
All patients will be recruited following completion of Partners approved protocol 2011P002376. If a 
subject has not successfully completed monitoring during protocol 2011P002376, s/he will not be 
eligible for enrollment into this study. The patient’s pre-therapy ambulatory monitoring from protocol 
2011P002376 will provide a baseline for deriving each patient’s vocal intensity biofeedback threshold. 
The overall design of the study will be three days: Two days of consecutive monitoring—a day of AVB 
(Day 1) and a subsequent day of ambulatory monitoring without AVB to assess if the desired vocal 
behavior is retained (Day 2). Seven days after Day 1, patients will wear the monitor again without 
AVB to assess any long-term retention of the desired vocal behavior (Day 3). As there is typically a 3-
4 week waiting period for beginning voice therapy at the MGH Voice Center, it is reasonable to 
assume that patients will have the required number of weeks available for this protocol before therapy 
commences. 
 
TABLE I. Study 1 time points and associated visits/procedures. 
 

Time Point One (Day 1) 
Time Point 2 (Day 2) 
Time Point 3 (Day 3) 
Visit to MGH Voice Center 
Visit to MGH Voice Center 
Visit to MGH Voice Center 
1. Investigator places 
VHM, marks the 
subject’s neck at 
location of sensor, 
programs VHM for 
subject’s biofeedback, 
starts recording. 
2. Investigator will teach 
subject how to use VHM 
and respond to 
biofeedback 
 
1. Investigator places 
VHM, marks subject’s 
neck at location of 
sensor, programs VHM, 
starts recording 
2. Investigator will review 
with subject how to use 
VHM 
 
 
1. Investigator places 
VHM, marks subject’s 
neck at location of 
sensor, programs VHM, 
starts recording 
2. Investigator will review 
with subject how to use 
VHM 
 
Recording of voicing in daily life 
Recording of voicing in daily life 
Recording of voicing in daily life 
1. Subject will wear device 
and receive feedback on 
how loud s/he talks 
2. Recording will 
automatically stop after 
42 minutes of phonation 
(approx. 7-10 hours) 
3. 
Subject will contact 
investigators to return 
device same day or charge 
device over night. 
1. Subject will wear device 
with no feedback 
2. Recording will 
automatically stop after 
42 minutes of phonation 
(approx. 7-10 hours) 
3. Subject will contact 
investigators to return 
device same day or 
charge device over 
night. 
1. Subject will wear device 
with no feedback 
2. Recording will 
automatically stop after 
42 minutes of phonation 
(approx. 7-10 hours) 
3. Subject will contact 
investigators to return 
device same day or 
charge device over 
night. 
 
During biofeedback days, the VHM will only monitor the first 50,000 voiced frames—which are 
approximately 42 minutes of phonation (“frame” = 50 ms)—to ensure that each patient gets an equal 
opportunity to experience biofeedback. At typical phonation times of less than 10%, 42 minutes of 
phonation is achieved within 7-9 hours of monitoring time, which is an attainable goal for all patients. 
 
The biofeedback threshold will be set at the 85th percentile of the patient’s baseline (weeklong) vocal 
intensity histogram and the patients will be provided biofeedback to reduce the upper 15 % of their 
vocal intensity distribution (dB). More specifically, the VHM will provide a 250 ms vibrotactile cue via a 
smartwatch—see Figure 2(c)—every frame (100% frequency) or every 4th frame (25% frequency) the 
amplitude exceeds the biofeedback threshold. Those in the summary feedback group will receive a 
vibrotactile cue on their smartwatch after every 2 minutes of voiced time to alert them that their 
summary statistics are ready to be viewed. To ensure that the patient looks at the summary statistics 
in a timely manner and accurately understands their scores, multiple screens for user-interaction will 
be provided (they must indicate the correct score) and patient responses will be recorded in a text 
document. 
 
The study endpoint will be achieved after satisfactory recording of 1 biofeedback day and two post-
biofeedback days (3 total days). 
 
Statistical Analysis Plan: 
Study One will use a series of two 3 (Group) X 4 (Day - baseline, biofeedback, short- and long-term retention) 
mixed between/within ANOVAs will be conducted for the outcome variables Δ dB and overall percentage 
compliance. The findings of interest are the main effects of “Day” and the interaction effects of Group X 
Day. While appropriate post hoc tests will be conducted on the main effects (if significance is achieved), 
univariate follow-up tests, and if required, appropriate post hoc tests will be performed on the interaction 
effects. Results from our preliminary research [6] produced large effect sizes (η2 ≈ 0.90) between the 
biofeedback and non-biofeedback/baseline time periods. Furthermore, both limb and head/neck motor 
learning studies have demonstrated large effect sizes (η2 = 0.70–0.95) between different feedback groups 
(decreasing frequency [10, 13-21, 49, 50] or delayed summary [10, 22-30, 51-53] feedback). Based on the 

lower effect size (η2 = 0.70) and the experimental design, power analysis indicated a sample of 14 participants 
per group with 80% power and alpha of 0.05. Since there are three experimental groups in Study One, the 
total sample size would need to be higher than 42 participants