Internet-based Cognitive Behavioral Therapy for Tinnitus Sufferers: Comparing the Full CBT Program With Relaxation Only Program
Phase: NA
Conditions: Tinnitus
Sponsor: Lamar University

 
Study Protocol and Statistical Analysis Plan 
 
 
Study Title: Dismantling internet-based cognitive behavioral therapy for tinnitus. The 
contribution of applied relaxation. A randomized controlled trial 
 
Clinical trial registration: NCT04004260 on April 03, 2020.  
 
Funding: This study was partly funded by the National Institute on Deafness and 
Communication Disorders (NIDCD) of the National Institute of Health (NIH) under the 
award number R21DC017214. 
 
Ethical approval: Institutional Review Board at Lamar University, Beaumont, Texas, US 
(IRB-FY20-200). 
 
Document Date: June 23, 2021 
 

 
Background 
Tinnitus, characterized by the perception of sound in the absence of an external stimulus, is 
one example of such a condition. Managing tinnitus is notoriously challenging as there is 
often not a curable medical cause. The intervention with strongest research evidence is 
cognitive behavioral therapy (CBT) for tinnitus. CBT is psychological intervention 
addressing unhelpful thought patterns and emotional reactions caused by tinnitus (Andersson, 
2002). Despite the evidence base, accessibility to CBT for tinnitus is limited due to a dearth 
of healthcare providers with the knowledge and expertise to provide CBT to this population 
(Bhatt et al., 2016; Henry et al., 2019).  
 
To overcome this barrier, an Internet-based CBT for tinnitus (ICBT; Andersson et al. 2002) 
has been developed. The efficacy of ICBT has been indicated in nine clinical trials across 
mainland Europe and the UK (for review see Beukes et al., 2019). However, no previous 
studies have examined the the importance od different components of CBT program.  
 
Objectives 
To seek ways of improving outcomes of ICBT, the aim of this study was twofold. Firstly, to 
dismantle the whole ICBT package against applied relaxation only. Secondly, to assess the 
intervention effects across different tinnitus subgroups. To our knowledge, this is the first 
ICBT trial to investigate the components of ICBT for tinnitus that are most meaningful and 
compare tinnitus subgroups. 
 
Study Design 
A randomized, prospective 2-arm intervention dismantling trial with a 2-month follow-up 
was undertaken. Participants were randomized to the full ICBT intervention or applied 
relaxation. During Phase I (8 weeks) the ICBT group was provided the full CBT intervention 
and the applied relaxation group received the applied relaxation sections. During Phase II (4 
weeks), the applied relaxation group was provided the remaining CBT components. This 
study design, therefore, provided the opportunity to evaluate the intervention effects in two 
independent groups at three different time points.   
 
Recruitment Strategy 
The participants were recruited from the general public using a range of strategies, including 
promoting the study via tinnitus support groups and the American Tinnitus Association 
(ATA) between 1 April to 4 May 2020. Further recruitment strategies included the use of 
social media (e.g., Facebook and Twitter), and also distributing flyers and posters to local 
health clinics (i.e., primary care physician, audiology, ENT) and communities and put up in 
clinic waiting rooms. Those interested were directed to the study website 
(www.tacklingtinnitus.org) where they could read more about the study, the university 
hosting the study, the research team, and how they could register interest in partaking in the 
study. Following registration, an online screening questionnaire (i.e., baseline assessment at 
T0) was completed. Participants were informed of their right to withdraw at any stage 
without penalty. 
 
Study Population 
 
The eligibility inclusion criteria included: adults, aged 18 years and over; living in the US; 
the ability to read and type in English; access to a computer, the internet and the ability to 
email; experiencing tinnitus for a minimum period of three months; any configuration of 
hearing levels (normal or any degree of hearing loss) and any use of hearing devices (using or 

 
not using hearing aids); and participants were included if they described a need for a tinnitus 
intervention and not based on their tinnitus outcome scores. 
 
The exclusion criteria were reporting pulsatile, objective, or unilateral tinnitus, which had not 
been investigated medically or tinnitus still under medical investigation; reporting any major 
medical condition or treatment that would prevent undertaking this intervention; and 
undergoing any tinnitus therapy concurrent with participation in this study. 
 
Participants were required to provide online consent to participate. Eligibility was determined 
by a two-stage process. Firstly, participants completed an online screening questionnaire, 
which included demographic information, health and mental health-related questions, and 
standardized outcome measures. After this, a telephone interview was conducted during 
which the researcher rechecked eligibility and provided the opportunity for potential 
participants to ask any questions related to the study. The study procedures were explained, 
and motivational interviewing was done to encourage participants to commit and engage in 
the intervention. Any participants with a score of 15 or more on the Patient Health 
Questionnaire–9 (PHQ-9) or indicated self-harm on question 10 received an additional phone 
consultation from a clinical psychologist on the research team. This call ensured that their 
depression was being managed and that they had the required resources and were not in any 
danger of self-harm. If the psychologist was assured that their depression was well managed 
they were eligible to participate in the study. 
 
Participants meeting the inclusion criteria were divided into three subgroups.  
i. 
Those with significant levels of tinnitus distress with scores of 25 or above on the 
Tinnitus Functional Index (TFI) which was used to measure tinnitus severity (i.e., 
high tinnitus severity group). 
ii. 
Due to numerous participants scoring below 25 and requesting help with their 
tinnitus, those with low tinnitus severity (<25 on the TFI) were included as a separate 
subgroup (i.e., low tinnitus severity group). 
iii. 
Those with high depression scores > 10 on the PHQ-9 or those answering positively 
for question 10, were added as a further subgroup (i.e., significant depression group).  
 
Sample Size, Power, and Attrition  
Sample size calculations were performed using the SampSize app for superiority parallel 
groups. Power was 90%; α was 0.025; and the estimated SD was 20 points, as indicated by 
the preceding pilot trial (Beukes et al., 2021b). The mean difference was set to 13 points, as 
indicated during the validation of the TFI (Meikle et al., 2012) to be a clinically significant 
change in scores. Thus, 51 participants were required for each arm. To ensure sufficient 
power, calculations for the larger sample were followed with the aim of recruiting 63 
participants per arm to inflate for possible missing data. 
 
Randomization 
Participants meeting the inclusion criteria were randomly assigned in the ratio of 1:1 after 
being stratified for tinnitus (<25 or ≥25 on the TFI) and depression (<10 or  ≥10 on the PHQ) 
and enrolled to either the ICBT or applied relaxation group using a computer-generated 
randomization scheduled by an independent research assistant in blocks of varying sizes. 
Participants and investigators could not be blinded to group allocation due to the nature of the 
intervention. The researchers were however blinded during data analysis. Participants were 
informed of their group allocation and when the intervention would commence by the 
principal investigator. 

 
 
Intervention 
The study employed a structured intervention based on a CBT for tinnitus program 
(Andersson & Kaldo, 2004; Beukes et al., 2021). This intervention was originally developed 
in Sweden (Andersson et al., 2002), and was later adapted into an interactive e-learning 
version for a UK population (Beukes, et al., 2016). To ensure suitability for a US population, 
the intervention was further modified with linguistic and cultural adaptions, such as lowering 
the readability to below the recommended 6th English reading grade level, (Beukes et al., 
2020a; Manchaiah et al., 2020b). The full program consists of 22 modules with explanatory 
videos, weekly homework assignments, worksheets and quizzes (Beukes et al., 2021). The 
intervention platform (Vlaescu et al., 2016) was housed in the US at Lamar University to 
comply with the needed data protection regulations. Prior to this trial, acceptability and 
functionality of this intervention for a US population were ensured (Manchaiah, et al., 2020a) 
and the intervention was piloted for a US population (Beukes et al. 2021a). Guidance was 
provided by an audiologist throughout the intervention. This included introducing the module 
content, monitoring progress, providing feedback on worksheets completed, outlining the 
content of new modules, answering questions, and encouraging questionnaire completion. 
Participants who were not engaging were contacted (messages/ text/ phone) to encourage 
engagement and discuss possible barriers, and an encrypted 2-way messaging system within 
the ePlatform was used to communicate with participants. Although psychologists have 
traditionally guided CBT interventions, tinnitus management is generally delivered by 
audiologists (Henry et al., 2019). Thus, an audiologist provided guidance to participants to 
maintain consistency with previous English trials using this intervention (Beukes et al., 2018, 
2021b).  
 
The groups accessed the intervention via a secure login, each group accessing different 
elements of the intervention along with different schedules as seen in Table 1. Both groups 
were asked to spend around 10 minutes a day practicing the suggested exercises and 
completing worksheets to monitor their progress.  
 
Table 1. The Intervention schedule for each group 
Week 
ICBT group schedule 
Applied relaxation group schedule 
Phase I 
22 modules 
10 modules 
1 
Program outline 
Tinnitus overview 
Program outline 
Tinnitus overview 
2 
Deep relaxation 
Positive imagery 
Sound enrichment 
Deep relaxation 
Positive imagery 
3 
Deep breathing 
Views on tinnitus 
Sleep guidelines 
Deep breathing 
 
4 
Entire body relaxation 
Shifting focus 
Improving focus 
Entire body relaxation 
5 
Frequent relaxation 
Thought Patterns 
Increasing sound tolerance 
Frequent relaxation 
6 
Relaxing when stressed or upset 
Challenging thoughts 
Listening tips 
Relaxing when stressed or upset 
7 
Relaxation routine 
Being mindful 

 
Listening to tinnitus 
8 
Summary 
Future planning 
Relaxation routine 
Phase II 
9 
N/A 
Views on tinnitus 
Thought patterns 
Sound enrichment 
10 
N/A 
Sleep guidelines 
Challenging thoughts 
Improving focus 
11 
N/A 
Shifting focus 
Listening to tinnitus 
Increasing sound tolerance 
12 
N/A 
Listening tips 
Summary 
Future planning 
 
Measures  
Data were collected online at baseline (T0); after the ICBT group completed the full ICBT 
intervention and the applied relaxation group completed only the relaxation part (T1); for the 
applied relaxation group after they completed the full ICBT intervention and compared the 
T1 results for the ICBT group (T2); and at 2-month post-intervention for both groups (T3). 
 
A demographic questionnaire was used to establish health-related and tinnitus-specific 
information at baseline (T0). A series of primary and secondary outcome measures were 
administered at baseline as well as during post-intervention.  
 
Primary Outcome Measure 
The primary outcome measure was tinnitus severity as measured by the TFI (Meikle et al., 
2012). It was selected over other tinnitus questionnaires as it was specifically developed to 
measure tinnitus severity and assess responsiveness to treatment and for comparison purposes 
with similar trials in the UK and the US (Beukes et al., 2017, 2018, 2021b). 
 
Secondary Outcome Measures 
The following secondary measures were incorporated to assess commonly reported 
tinnitus-related difficulties:  
§ The Generalized Anxiety Disorder–7 (GAD-7; Spitzer et al., 2006) assessed symptoms of 
generalized anxiety disorder.  
§ The PHQ-9 (Spitzer, Kroenke, Williams, 1999) indicated symptoms of depression. 
§ The Insomnia Severity Index (ISI; Bastien, Vallières, & Morin, 2001) assessed the 
presence of insomnia. 
§ The Tinnitus Cognitions Questionnaire (TCQ; Wilson & Henry, 1998) was used to 
measure negative tinnitus cognitions. 
§ The EQ-5D-5L (Herdman et al., 2011) measured general health-related quality of life. 
§ The Tinnitus and Hearing Survey (THS; Henry et al., 2015) was used as a short measure 
to identify participants’ tinnitus severity, hearing disability, and hyperacusis. 
 
Intervention Variables 
Intervention compliance was assessed by determining retention rates and compliance in 
completing outcome questionnaires. Intervention engagement was assessed by the number of 

 
logins, the number of modules opened, and the number of messages sent during the 
intervention.  
 
Statistical Analysis Plan 
Statistical analyses were performed using the Statistical Package for Social Sciences (SPSS) 
version 26.0. All statistical tests were 2-tailed with an alpha set to .05. For transparency, both 
an intention-to-treat approach including all participants, and a completers-only analysis was 
undertaken for comparison purposes. For the intention-to-treat model, an imputation analysis 
was undertaken. Missing data were handled through multiple imputations using the Markov 
Chain Monte Carlo approach. The analysis thus included all participants at each time point.  
 
The primary study outcome was a change in TFI score between groups at post-intervention 
(T1). Secondary study outcomes were changes in secondary outcomes between groups at T1. 
According to recommendations for statistical analysis of internet interventions (Hesser, 2015) 
effect sizes, Linear Mixed Effects Models (LMM), and the Reliable Change Index (RCI) was 
used to assess the outcomes. Changes from baseline to post-intervention were compared 
within and between groups using the standardized mean differences (Cohen’s d) for all 
primary and secondary outcomes using the observed data. Effect sizes of d = 0.20 represent 
small effect sizes; those of d = 0.50, medium effect sizes; and those equal or greater than d = 
0.80, large effect sizes (Cohen, 1992).  
 
The LMM, which provided unbiased results in the presence of missing data (using all 
available data) was applied to analyze the intervention effect accounting for the repeated 
measurements. An unstructured repeated effect and identify random effects covariance 
structure provided the best model fit based on the Akaike’s Information Criterion (AIC). 
Time was treated as a repeated and fixed effect. Restricted maximum likelihood estimation 
was applied. The Type III F test sums of squares from the LMM are presented. As a 
sensitivity analysis, baseline tinnitus severity was initially added as a covariate. As it had no 
significant effect on the results, it was removed from the model. Subgroup analysis was 
performed for the three pre-defined subgroups to compare outcomes between them. 
 
The RCI (Jacobson & Truax, 1991) was used as a standardized way of calculating clinical 
significance for the TFI as the primary outcome. This was calculated using the mean pretest-
posttest score difference, the pretreatment standard deviation (26.00), and a test-retest 
reliability coefficient of 0.78, and as reported in the validation study (Meikle et al., 2012).  
 
Sample Characteristics  
Descriptive statistics including gender, age, ethnicity, race, tinnitus duration, hearing aid use, 
and professionals consulted, ease of computer use, veteran status, education, and employment 
status were used to describe the sample. The mean and standard deviation were reported for 
each outcome measure at each time point. Descriptive statistics were also used to assess the 
sample and intervention engagement including the number of logins and modules opened. A 
Chi-square test of independence was used to identify group differences regarding engagement 
and compliance rates. 
 
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