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Study on Botulinum Toxin A for Tinnitus in Patients with Bruxism or Jaw Muscle Pain

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects of a treatment for patients who have tinnitus, a condition where individuals hear ringing or other noises in one or both ears. The study is particularly interested in those who also experience bruxism (teeth grinding) and/or jaw muscle myalgia (muscle pain in the jaw). The treatment being tested is an injection of Botulinum toxin type A, commonly known as BOTOX. This study will compare the effects of BOTOX injections to a placebo to see if it can help reduce the symptoms of tinnitus, bruxism, and jaw muscle pain.

The purpose of the study is to explore whether BOTOX can improve the quality of life for those suffering from these conditions. Participants will receive injections and will be monitored over a period of time to assess any changes in their symptoms. The study will involve a series of visits where participants will receive either the BOTOX treatment or a placebo, and their progress will be tracked through questionnaires and assessments.

Throughout the study, participants will be asked to report on their tinnitus symptoms, headache levels, and jaw muscle pain. The study aims to determine if there is a significant difference in symptom improvement between those receiving the BOTOX treatment and those receiving the placebo. This research hopes to provide new insights into managing tinnitus and related conditions effectively.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, you will be asked to sign a written informed consent form. This confirms your understanding and agreement to participate in the trial.

    You must be 18 years or older and have experienced tinnitus in one or both ears for more than three months. Your hearing will be assessed as normal through a hearing test called audiometry.

    You should have severe bruxism (teeth grinding) and/or jaw muscle pain, and other treatments should not have helped alleviate these symptoms.

    You will need to complete forms in the Norwegian language, including the Tinnitus Handicap Inventory (THI) and a quality of life questionnaire (QoL-EQ-5D-5L).

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to evaluate your baseline condition. This includes measuring your THI score, which should be greater than 40.

    Your headache and jaw muscle pain will be assessed using a Visual Analog Scale (VAS), where a score of 1 or higher is required.

  3. Step 3

    Treatment phase

    During the treatment phase, you will receive injections of botulinum toxin type A or a placebo. The injections will be administered through intramuscular injection.

    The treatment will be conducted in a triple-blind, randomized, placebo-controlled cross-over manner, meaning neither you, the healthcare provider, nor the researchers will know if you are receiving the active treatment or placebo at any given time.

  4. Step 4

    Follow-up assessments

    Follow-up assessments will be conducted to monitor changes in your condition. These assessments will occur at various intervals up to week 18.

    The primary focus will be on the change in your THI score from the start of the trial to week 18.

    Secondary assessments will include changes in headache and jaw muscle pain scores using the VAS, as well as changes in your quality of life score using the EQ-5D-5L questionnaire.

  5. Step 5

    Completion of the trial

    Upon completion of the trial, the results will be analyzed to determine the effectiveness of the treatment.

    Your participation will contribute to understanding the potential effects of botulinum toxin type A on tinnitus in patients with concurrent bruxism and/or jaw muscle pain.

Who can join the trial?

10 criteria

  • Participant must be 18 years or older.
  • Participant has had tinnitus (ringing or noise in the ears) in one or both ears for more than three months.
  • Participant has a THI score (Tinnitus Handicap Inventory, a questionnaire to measure the impact of tinnitus) at screening greater than 40.
  • Participant's hearing was assessed as normal by audiometry (a test to check hearing ability).
  • Participant presents with severe bruxism (teeth grinding or clenching) as assessed by a neurologist, and other treatments have not been enough to relieve symptoms.
  • VAS score (Visual Analogue Scale, a tool to measure pain intensity) for headache is 1 or higher.
  • VAS score for jaw muscle pain is 1 or higher.
  • Participant can understand and complete the forms (THI and QoL-EQ-5D-5L, a questionnaire to measure quality of life) in the Norwegian language.
  • If the participant is a woman of childbearing potential, she must be using highly effective contraception.
  • Signed written informed consent is required, meaning the participant agrees to take part in the study after understanding all the details.

Who cannot join the trial?

4 criteria

  • Patients who are not between the ages of 18 and 65 cannot participate.
  • Patients who do not have tinnitus (a ringing or buzzing noise in one or both ears) cannot participate.
  • Patients who do not have bruxism (a condition where you grind, gnash, or clench your teeth) or jaw muscle myalgia (muscle pain in the jaw) cannot participate.
  • Patients who are part of a vulnerable population, such as those unable to give consent, cannot participate.
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Investigated drugs

Botulinum toxin A is a medication used in this clinical trial. It is commonly known for its ability to relax muscles. In this study, it is being tested to see if it can help reduce the symptoms of tinnitus, which is a ringing or buzzing noise in the ears. The trial is specifically looking at patients who also have bruxism, which is a condition where people grind or clench their teeth, and/or jaw muscle myalgia, which is pain in the jaw muscles. The idea is that by relaxing the muscles, the medication might help alleviate the tinnitus symptoms in these patients.

What is already known about the treatment

Botulinum toxin A – This medication is administered through injections and is currently being studied for its effects on tinnitus, especially in patients who also suffer from teeth grinding (bruxism) or jaw muscle pain (myalgia). In medical literature, Botulinum toxin A is well-known for its ability to relax muscles by blocking nerve signals that cause muscle contractions. It is primarily used for conditions involving muscle stiffness or spasms. The main therapeutic indication in this trial is to assess its potential benefits for tinnitus relief. Botulinum toxin A works at the molecular level by preventing the release of a neurotransmitter called acetylcholine, which is responsible for muscle contraction, thereby reducing muscle activity. It is classified pharmacologically as a neuromuscular blocker.

Investigated diseases

Tinnitus – Tinnitus is a condition characterized by the perception of noise or ringing in the ears when no external sound is present. It is often described as a ringing, buzzing, hissing, or whistling sound. The condition can vary in intensity and may be constant or intermittent. Tinnitus can be associated with hearing loss, ear injury, or circulatory system disorders. It may also be linked to stress, anxiety, or exposure to loud noises. Over time, tinnitus can affect concentration and sleep, leading to further discomfort.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-518256-23-00Protocol codeTinnitoxEstimated enrolment100 patientsSponsorSorlandsklinikken

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