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Trial registered on ANZCTR


Registration number
ACTRN12616000742471
Ethics application status
Approved
Date submitted
26/05/2016
Date registered
6/06/2016
Date last updated
6/06/2016
Type of registration
Retrospectively registered

Titles & IDs
Public title
Randomised controlled trial on long- term sound therapy using predictable and unpredictable sounds in adults with constant tinnitus
Scientific title
Randomised controlled trial on the effect of long- term sound therapy using predictable and unpredictable sounds in adults with constant tinnitus
Secondary ID [1] 289306 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Tinnitus 298901 0
Condition category
Condition code
Ear 298977 298977 0 0
Other ear disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This study was a randomized control trial with a cross-over design involving the use of take home MP3 players and in-ear phones, containing recorded predictable and unpredictable tinnitus relief sounds, which the participant listened to for a minimum of one hour per day for sixteen weeks (8 weeks predictable, 8 weeks unpredictable sounds). All stimuli (predictable and unpredictable sounds) were adjusted for sound level such that long-term average loudness (dB SPL) was equivalent. There was a three week wash-out period in between the two conditions.

13 participants were administered the Predictable condition first and 12 participants administered the Unpredictable condition first. All participants were tested by the student investigator throughout the trial. Adherence to intervention was monitored by email communication every two weeks (beginning with the date of sound fitting) which asked participants how the sound trial was going, if they have any concerns or queries, any special circumstances, etc. In-between follow-up appointments were made as needed. The interviews at each follow-up appointment also monitored adherence and addressed any concerns which arose.

Predictable sound therapy

a) Broadband noise (BBN) set at the volume such that it was comfortable, and at the minimal level at which the sound started to interfere with their tinnitus.

b) Frequency of stimulation: Minimum 1 hour per day for 8 continuous weeks

d) Mode of administration: MP3 file participants listened to using a Phillips ViBe 4GB MP3 player + Panasonic in-ear phones (RP-HJE290) with Budloks Sport Grip

Unpredictable sound therapy

a) Beach surf, Cicadas/Farm Sounds and Rain sounds directly recorded from the natural setting by the researchers and edited. Participants selected which sound they preferred to use in the trial. In use participants were asked to set the volume of sound such that it was comfortable, and at the minimal level at which the sound started to interfere with their tinnitus.

b) Frequency of stimulation: Minimum 1 hour per day for 8 continuous weeks

d) Mode of administration: MP3 file participants listened to using a Phillips ViBe 4GB MP3
player + Panasonic in-ear phones (RP-HJE290) with Budloks Sport Grip
Intervention code [1] 294864 0
Treatment: Devices
Comparator / control treatment
The comparator treatment is neutral broadband noise (Predictable) which positive, environmental sound (Unpredictable) is being compared against for the various intervention outcomes.
Control group
Active

Outcomes
Primary outcome [1] 298454 0
Tinnitus impact on life scores measured using total Tinnitus Functional Index (TFI) scores
Timepoint [1] 298454 0
Baseline (when sounds are given to each participant), at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Primary outcome [2] 298524 0
Tinnitus severity assessed using Tinnitus Loudness and Severity rating scales (1-10)
Timepoint [2] 298524 0
Baseline (when sounds are given to each participant), at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Primary outcome [3] 298525 0
Tinnitus psychoacoustic matches of loudness (Loudness Level Matching in dB SL) matched wusing custom Tinnitus Software (Registered Trademark, The University of Auckland)
Timepoint [3] 298525 0
Baseline (when sounds are given to each participant), at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [1] 324154 0
Alertness needed for general cognitive task performance assessed using the Reaction Time Task from the Computerized Attention Battery Version 5 (Registered Trademark).
Timepoint [1] 324154 0
Baseline and at 8 week follow-up for each intervention sound.
Secondary outcome [2] 324155 0
Depression assessed using the Depression, Anxiety and Stress Scale (DASS Scale)
Timepoint [2] 324155 0
Baseline when sound is first given to the participant, at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [3] 324453 0
Tinnitus psychoacoustic matches of masking levels (Minimum masking level in dB SL) matched wusing custom Tinnitus Software (Registered Trademark, The University of Auckland)
Timepoint [3] 324453 0
Baseline when sound is first given to the participant, at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [4] 324454 0
Anxiety assessed using the Depression, Anxiety and Stress Scale (DASS Scale)
Timepoint [4] 324454 0
Baseline when sound is first given to the participant, at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [5] 324455 0
Stress assessed using the Depression, Anxiety and Stress Scale (DASS Scale)
Timepoint [5] 324455 0
Baseline when sound is first given to the participant, at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [6] 324456 0
Positive emotionality (level of positive emotions experienced by the individual) over the week prior to the appointment assessed using the Positive and Negative Affect Schedule
Timepoint [6] 324456 0
Baseline when sound is first given to the participant, at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [7] 324457 0
Negative emotionality (level of negative emotions experienced by the individual) over the week prior to the appointment assessed using the Positive and Negative Affect Schedule
Timepoint [7] 324457 0
Baseline when sound is first given to the participant, at 4 week follow-up and 8 week follow-up appointment for each intervention sound.
Secondary outcome [8] 324458 0
Focused attention levels assessed using the Discrimination Reaction Time Task from the Computerized Attention Battery Version 5 (Registered Trademark).
Timepoint [8] 324458 0
Baseline and at 8 week follow-up for each intervention sound.

Eligibility
Key inclusion criteria
Adults aged between 18-65 years residing in the Auckland region with constant tinnitus and a minimum score of 38 on Tinnitus Functional Index (TFI), normal middle ear function and at maximum a moderate degree of hearing loss (less than 70 dB on average across frequencies).
Minimum age
18 Years
Maximum age
65 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
- Age is younger than 18 or over 65
- Do not experience constant tinnitus
- Presence of middle ear pathology at the time of testing (e.g. glue ear)
- Presence of a hearing loss greater than moderately severe (greater than 70 dB on average across frequencies).

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Existing volunteers from the University of Auckland Tinnitus Database were approached via email – a participant information sheet (PIS) and consent form (CF) were attached along with the study invite. These were individuals who have expressed interest in participating in tinnitus research. Interested individuals contacted the student investigator by email or phone.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The order of Intervention presentation (Order 1 = Predictable then Unpredictable OR Order 2 = Unpredictable then Predictable) for participants was decided using an online, free True Random Number Generator (https://www.random.org/). Each participant was given a code number from 1-24. Participants whose codes matched the first 17 generations of the random sequence were assigned Order 1, the remaining participants were assigned into Order 2.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
All participants were tested by the same researcher throughout the trial. The only blinding applied was participants were not shown the results of their tinnitus outcome measures at the different time points until the end of the trial. Blinding to intervention type could be given due to the distinct perceptual sound characteristics of the two sound stimuli.
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Based on Wise et al. (2012, Unpublished thesis) data for tinnitus population variance for a significant change of 13 on TFI, with mean 28.15 and standard deviation 17.1 (one-tailed), significance 0.05 and power 0.8, the sample size needed was 11 (Wise, 2012). 25 participants were therefore determined as being sufficient for this trial.

The difference between the two groups in mean changes in the intervention outcome between 4 and 8 weeks of intervention and baseline were obtained using analysis of covariance (ANCOVA), adjusting for baseline. Covariates of age, gender, and degree of hearing loss (categorized as slight, mild, moderate, moderately severe, severe or profound (ASHA, American Speech and Hearing Association) (Clark, 1981) based on average of 3000, 4000 and 6000 Hz hearing thresholds bilaterally) were also added in a second model and re-run for 4 weeks and 8 weeks follow-up. In cases where a significant main effect was observed, Bonferroni post-hoc tests were administered.

The framework method (Gale et al., 2013) was used to analyse the qualitative interviews, consisting of five steps: familiarization, identification of a thematic framework, indexing, charting, and mapping and interpretation.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 7909 0
New Zealand
State/province [1] 7909 0
Auckland

Funding & Sponsors
Funding source category [1] 293689 0
University
Name [1] 293689 0
University of Auckland PReSS (Postgraduate Research Student Support) Fund
Address [1] 293689 0
University of Auckland Tamaki Campus, 261 Morrin Road, Glen Innes, Auckland 1072.
Country [1] 293689 0
New Zealand
Primary sponsor type
Individual
Name
Mithila Durai
Address
Section of Audiology, Level 3, Building 730, University of Auckland Tamaki Campus, 261 Morrin Road, Glen Innes, Auckland 1072.
Country
New Zealand
Secondary sponsor category [1] 292522 0
Individual
Name [1] 292522 0
Dr. Grant D Searchfield
Address [1] 292522 0
Section of Audiology, Level 3, Building 730, University of Auckland Tamaki Campus, 261 Morrin Road, Glen Innes, Auckland 1072.
Country [1] 292522 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 295126 0
University of Auckland Human Participants Ethics Committee
Ethics committee address [1] 295126 0
Research Office, Level 10, Building 620, 49 Symonds Street, Auckland 1072.
Ethics committee country [1] 295126 0
New Zealand
Date submitted for ethics approval [1] 295126 0
27/05/2015
Approval date [1] 295126 0
03/06/2015
Ethics approval number [1] 295126 0
014520

Summary
Brief summary
Mechanisms of tinnitus (phantom sound) perception and sound therapy (treating tinnitus using sounds) are still poorly understood. Understanding such mechanisms can enable for
developing better interventions/treatments for tinnitus sufferers. It is of interest to administer a randomized control sound therapy trial comparing the effectiveness of predictable and unpredictable sounds for tinnitus relief. It is also of interest to see how the emotional component of sounds may influence its effectiveness as a tinnitus treatment sound. Aim: Understand how sound therapy of long-term duration using predictable and unpredictable sounds affects tinnitus characteristics. Hypotheses: Administration of unpredictable sound therapy will result in lower tinnitus loudness and distress outcomes than predictable sound therapy. Tinnitus treatment sounds which evoke positive, relaxed emotions (high valence) will result in lower tinnitus loudness and distress outcomes than static, neutral sounds.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 66198 0
Dr Grant D Searchfield
Address 66198 0
Section of Audiology, Level 3, Building 730, University of Auckland Tamaki Campus, 261 Morrin Road, Glen Innes, Auckland 1072.
Country 66198 0
New Zealand
Phone 66198 0
+64 9 923 6316
Fax 66198 0
Email 66198 0
g.searchfield@auckland.ac.nz
Contact person for public queries
Name 66199 0
Dr Grant D Searchfield
Address 66199 0
Section of Audiology, Level 3, Building 730, University of Auckland Tamaki Campus, 261 Morrin Road, Glen Innes, Auckland 1072.
Country 66199 0
New Zealand
Phone 66199 0
+64 9 923 6316
Fax 66199 0
Email 66199 0
g.searchfield@auckland.ac.nz
Contact person for scientific queries
Name 66200 0
Ms Mithila Durai
Address 66200 0
Section of Audiology, Level 3, Building 730, University of Auckland Tamaki Campus, 261 Morrin Road, Glen Innes, Auckland 1072.
Country 66200 0
New Zealand
Phone 66200 0
+64272735215
Fax 66200 0
Email 66200 0
m.aruldasan@auckland.ac.nz

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary