Independent academic RCTs Peer-reviewed publications

The evidence behind Oto

Oto is one of the few tinnitus apps to be studied in independent, university-led randomized controlled trials. Two RCTs have enrolled 306 participants: a 96-participant Flinders University trial (published 2025) and the 210-participant Cambridge-led DEFINE trial, with results currently in peer review.

2 Independent university RCTs
306 Participants enrolled
2025 First peer-reviewed paper
13.5 Years follow-up combined

Research partners and funders

DEFINE trial lead

Flinders RCT lead

DEFINE clinical partner

DEFINE co-funder

Has Oto been studied in a clinical trial?

Yes. Oto has been the subject of two independent university-led randomized controlled trials: a 96-participant trial led by Flinders University (published 2025) and a 210-participant trial led by the University of Cambridge (the DEFINE trial; results in peer review). Trial registrations and publications are listed below.

Summary

At a glance

  • Two independent academic RCTs of Oto have been conducted to date. A 96-participant trial at Flinders University (published 2025 in Speech, Language and Hearing) and a 210-participant trial at the University of Cambridge (the DEFINE trial; results in peer review).
  • The DEFINE trial is, to our knowledge, the largest randomized controlled trial of a smartphone app for tinnitus conducted to date. Design: randomized, decentralized. Trial registration: ISRCTN99577932. Protocol: PLOS ONE, January 2024.
  • Patient education and sound therapy are recognized components of tinnitus management in the AAO-HNS clinical practice guideline for tinnitus.
  • To our knowledge, most tinnitus apps have not been studied in a published randomized controlled trial. Oto is one of the few exceptions.
  • Both trials were independently conducted by academic teams, and partially funded by Oto Health Ltd alongside non-commercial co-funders: Flinders University (Flinders trial) and the UK government’s innovation agency, Innovate UK (DEFINE).

Expert consensus

What the guidelines say about tinnitus management

Patient education and sound therapy are recognized components of tinnitus management in the American Academy of Otolaryngology, Head and Neck Surgery (AAO-HNS) clinical practice guideline, the US guideline for tinnitus. Guidance does not describe any approach as silencing tinnitus. The aim of management is to reduce the impact tinnitus has on daily life.

AAO-HNS
United States
Clinicians should educate patients with persistent, bothersome tinnitus about management strategies.
AAO-HNS Clinical Practice Guideline · Tinnitus · 2014, reaffirmed
AAO-HNS
United States

The American Academy of Otolaryngology, Head and Neck Surgery (AAO-HNS) publishes the US clinical practice guideline for tinnitus. It sets out how clinicians should evaluate tinnitus and which management approaches to consider, and it recognizes patient education and sound therapy among them.

AAO-HNS Clinical Practice Guideline · Tinnitus · 2014, reaffirmed

Key takeaways

  • Tinnitus management in clinical guidance centers on evaluation, patient education and reducing the impact tinnitus has on daily life.
  • Patient education and sound therapy are recognized components of tinnitus management in the AAO-HNS clinical practice guideline.
  • No approach is described in guidance as silencing tinnitus.
  • Oto is the subject of two independent university randomized controlled trials, listed below.

Tinnitus specialists near you

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The program

How Oto works

Oto is a smartphone app used alongside the patient’s own clinician. It gives the user an adjustable library of sounds, together with audio sessions covering education, relaxation and mindfulness and exercises drawing on cognitive behavioral techniques. It runs on iOS and Android and is used at home between appointments.

Independent RCTs

Clinical research on Oto

Oto is the subject of two independent university-led randomized controlled trials. Below are the trials in order of size and rigour, followed by a brief note on the in-house pilot work that preceded them.

TrialInstitutionDesignParticipantsStatusFundingCitation
DEFINEUniversity of CambridgeRCT, decentralized210In peer reviewInnovate UK + Oto Health LtdProtocol: Smith et al., PLOS ONE, 2024
Flinders RCTFlinders UniversityRCT, wait-list control, CONSORT-adherent96 (50 / 46)PublishedFlinders University + Oto Health LtdMui et al., Speech, Language and Hearing, 2025

Independent RCT · Cambridge

The DEFINE trial

University of Cambridge · Randomized controlled trial

In peer review

The DEFINE trial (Digital thErapy For Improved tiNnitus carE Study) is a randomized, decentralized study of Oto in adults with chronic tinnitus. Enrolment of 210 participants completed in 2025. The trial was led by Matt Smith, Assistant Research Professor at the University of Cambridge and Principal Investigator on DEFINE, in collaboration with the Cambridge University Hospitals NHS Foundation Trust. The trial was partially funded by the UK government’s innovation agency, Innovate UK, with additional sponsorship from Oto Health Ltd. The protocol was published open-access in PLOS ONE in January 2024. DEFINE used a decentralized design: recruitment, interventions, and assessments were conducted remotely, enabling UK-wide participant involvement without requiring clinic visits. Results are currently undergoing peer review and will be added here on publication. To our knowledge, DEFINE is the largest randomized controlled trial of a smartphone app for tinnitus conducted to date.

Participants

210

Design

Randomized controlled trial

Methodology

Decentralized

Registration

ISRCTN99577932

Protocol

PLOS ONE · Jan 2024

DOI

10.1371/journal.pone.0292562

Funders

Innovate UK + Oto Health

Independent RCT · Flinders

The Flinders University RCT

Flinders University, Australia · Wait-list controlled RCT · CONSORT-adherent

Published

The Flinders University trial is a 96-participant randomized controlled trial of Oto against a wait-list control over nine months, led by Boaz Mui and the team at Flinders University’s College of Education, Psychology and Social Work and Digital Health Research Centre. The trial was CONSORT-adherent and registered with the Australian New Zealand Clinical Trials Registry (ACTRN12623001138673). The study was partially funded by Flinders University, with additional sponsorship from Oto Health Ltd.

“Use of Oto demonstrated statistically significant results in reducing tinnitus severity and distress at 6 months, with effects sustained at 9 months.”

The authors, reported in Speech, Language and Hearing (Mui et al., 2025)

Participants

96

50 intervention / 46 wait list

Design

Wait-list controlled RCT

Duration

9 months follow-up

Registration

ACTRN12623001138673

Publication

Read paper →

Note · earlier in-house pilot work (2021). An in-house pilot of an earlier version of Oto was conducted in 2021. It informed the design of the subsequent independent academic trials at Cambridge and Flinders. It was not peer-reviewed.

Key takeaways

  • Oto has been studied in two independent academic randomized controlled trials at the University of Cambridge and Flinders University, enrolling 306 participants in total.
  • The Flinders RCT was published open-access in Speech, Language and Hearing in 2025. The authors reported statistically significant reductions in tinnitus severity and distress at 6 months, sustained at 9 months (Cohen’s d = 0.62 at 6 months).
  • The DEFINE trial (Cambridge) is a 210-participant randomized, decentralized trial of Oto in adults with chronic tinnitus. Results are currently in peer review.
  • DEFINE was co-funded by the UK government’s innovation agency, Innovate UK, alongside Oto Health Ltd.
  • Both trials were designed, conducted, and analyzed independently by the academic teams at the respective universities.

For clinicians and audiologists

Oto offers a 12-month tinnitus program for independent audiology practices: the Oto app, provider certification, clinical workflows, and ongoing support.

See Oto for clinicians →

From the researchers

In their own words

Two quotes from named, credentialed voices on study design and rigour. Outcome quotes will appear on DEFINE publication.

Matt Smith, MA, PhD, FRCS (ORL-HNS)

Matt Smith

MA, PhD, FRCS (ORL-HNS)

Assistant Research Professor, University of Cambridge · Principal Investigator, DEFINE Trial

DEFINE was designed as a randomized, decentralized trial run at scale, because the tinnitus field has had very few adequately powered randomized trials of app-delivered care. Running it decentrally, with participants taking part from home rather than attending a research clinic, allowed recruitment across the UK rather than around a single site.
Dr Evan Davies, AuD, CH-TM

Dr Evan Davies

AuD, CH-TM

Head of Clinical Innovation at Oto · Tinnitus and Sound Sensitivity Specialist

Oto sponsors trials and then steps out of the way. The researchers at Cambridge and Flinders designed the studies, ran them, and analyzed the data independently. That’s the kind of evidence base I’d want to point a patient to as a clinician.

Common questions

Frequently asked questions

  1. Has Oto been studied in a clinical trial? 01

    Yes. Oto has been the subject of two independent university-led randomized controlled trials: a 96-participant trial led by Flinders University (published 2025) and a 210-participant trial led by the University of Cambridge (the DEFINE trial; results in peer review). Trial registrations and publications are listed under "Clinical research on Oto" above.

  2. What is the Tinnitus Functional Index (TFI)? 02

    The TFI is a validated 25-item questionnaire used to measure tinnitus severity and its impact on daily life. Scores range from 0 to 100, with higher scores indicating greater severity. The TFI is used as a primary outcome measure in the academic trials of Oto and in tinnitus research generally (Meikle et al., 2012).

  3. Who funded the research on Oto? 03

    Both academic trials of Oto were partially funded by Oto Health Ltd, alongside non-commercial co-funders. The Flinders University trial was co-funded by Flinders University. The Cambridge DEFINE trial was co-funded by the UK government’s innovation agency, Innovate UK. Trial design, conduct, statistical analysis, and reporting were carried out independently by the academic teams at the host universities. Conflict of interest declarations are published in each paper.

  4. What does clinical guidance recommend for tinnitus? 04

    The AAO-HNS clinical practice guideline for tinnitus sets out how clinicians should evaluate tinnitus and which management approaches to consider. Patient education and sound therapy are recognized components of tinnitus management within it. No approach is described in guidance as silencing tinnitus; the aim is to reduce the impact tinnitus has on daily life.

  5. How is Oto’s research conducted? 05

    The independent academic trials of Oto (Cambridge DEFINE, Flinders University) follow the international standards expected for clinical research: pre-registered protocols, ethics committee approval, validated outcome measures (TFI), and peer review of results. The DEFINE trial used a decentralized methodology: participants took part from their homes rather than visiting a research clinic.

  6. Can I participate in Oto research? 06

    Oto runs research studies from time to time. If you are interested in participating in a future study, contact us at support@joinoto.com.

  7. Where can I find the published papers? 07

    The Flinders University trial is published open-access in Speech, Language and Hearing (2025). The DEFINE trial protocol is published open-access in PLOS ONE (January 2024, DOI: 10.1371/journal.pone.0292562). Direct links are in the "Clinical research on Oto" section above. The DEFINE results paper will be linked here on publication.

Tinnitus specialists near you

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Methodology

Our commitment to evidence

Sponsorship and independence

Both academic trials of Oto were partially funded by Oto Health Ltd, alongside non-commercial co-funders. The Flinders University trial was co-funded by Flinders University. The Cambridge DEFINE trial was co-funded by Innovate UK, the UK government’s innovation agency. Trial design, conduct, statistical analysis, and reporting were carried out independently by the academic teams at the host universities. Conflict of interest declarations are published in each paper.

Validated outcome measures

The trials use the Tinnitus Functional Index (TFI), a validated 25-item questionnaire (Meikle et al., 2012) widely used in tinnitus research. A TFI reduction of 13 points or more is generally considered clinically meaningful.

Meikle et al., 2012 →

Decentralized trial design

The DEFINE trial used a decentralized design: recruitment, interventions, and assessments were conducted remotely, enabling UK-wide participant involvement without requiring clinic visits. Decentralized designs are increasingly used in clinical research to improve access and reduce participant burden. The full methodology is described in the DEFINE protocol paper (Smith et al., PLOS ONE, 2024).

DEFINE protocol →

How to cite this page

Oto Health. The evidence behind Oto. joinoto.com/research. Last reviewed 20 May 2026. Medical reviewer: Professor Jameel Muzaffar, FRCS.

Next

Three ways to engage with the evidence.

For media

For journalists and media

For interviews, supporting material, embargoed access to DEFINE results once available, or biographies of the research team, contact our press team.

Contact press team → press@joinoto.com For clinicians

For clinicians and audiologists

Oto offers a 12-month tinnitus program for independent audiology practices that includes the Oto app, provider certification, clinical workflows, and ongoing support.

See Oto for clinicians → For patients

For people with tinnitus

Oto is available through independent audiology practices across the US. Find a provider near you to learn more about the program.

Find a provider →

Wondering what it costs? See how Oto pricing and access work. Or see how Oto's evidence compares with other tinnitus apps.

Medically reviewed

Medically reviewed by Professor Jameel Muzaffar, FRCS · ENT Surgeon, Co-Founder & CSO Oto Health Last reviewed: 20 May 2026.