In This Study, we Are Testing Whether Combining Two Interventions, in the Early Stages of Tinnitus, is More Effective in Quieting Tinnitus Than Using One Treatment Alone in the Later Stages of Tinnitus

Tinnitus is a common condition, in which people hear continuous sounds in the absence of an external source producing those sounds. Most people experience tinnitus for short periods of time throughout their life, for instance after exposure to loud noise, and some people experience long-term tinnitus. In most cases of tinnitus, there is a degree of hearing loss (often only mild), but it is rare for tinnitus to represent any serious disorder of the brain or ear. There are no widely effective treatments for tinnitus to reduce its loudness or eliminate it, but the majority of people with long-term tinnitus lead a normal life, without any impairment in quality of life on account of the tinnitus. A minority of people with long-term tinnitus experience distress as a result of it, and most people with long-term tinnitus gradually get used to the sound, and notice it less and less over time.

Previous studies have shown that applying a weak electrical current to the scalp (electrical stimulation) can lead to a small reduction in the loudness and impact of tinnitus for some people who have had tinnitus for many months or years already, and that this is significantly more effective, on average, than applying placebo (i.e. pretend) electrical stimulation. Electrical stimulation has never been tested in people who have recently developed their tinnitus.

Certain specific sounds, tailored to individuals' tinnitus, can significantly quieten tinnitus for some people, when these are listened to for an hour or so each day for weeks or months. However, the average quieting effect is quite modest. Like with electrical stimulation, these have only been tested by people with tinnitus already present for months to years.

Aims of study

The researchers believe that electrical stimulation and tailored sounds may be more effective in quieting tinnitus when given early in the course of tinnitus, compared to later on. Many researchers also believe that combining different types of tinnitus treatment may have a stronger effect than the sum of the effects of each individually.

Finally, the researchers want to test whether using interventions to quieten tinnitus early on in its course, even just for one month, might have a long-lasting or permanent effect in reducing tinnitus symptoms.

The benefits of treating tinnitus early, and using combination interventions, are currently theoretical, and one main aim of the study is to test whether they do exist.

The other main aim is to see how acceptable people find the course of combined intervention in the time period shortly after their tinnitus begins.

The volunteers are being approached because the volunteers have indicated that they have newly developed tinnitus.

What taking part involves

If they take part in the study, they will attend the researcher's laboratory on a total of 10 sessions over one month, to do the following:

• Provide details about their tinnitus and other health symptoms, and complete questionnaires (sessions 1 and 10 only)
• Undergo a hearing test (session 1 only). Note that this is not a substitute for having the volunteer's hearing formally assessed in a clinic.
• Undergo some computer-based sound tests (sessions 1 and 10 only). In these, they match a sound to the volume and pitch of their tinnitus so the researchers can estimate what it sounds like.
• Having an electroencephalography (EEG) recording, which measures their electrical 'brainwaves' (sessions 1 and 10 only)
• Have an electrical stimulation session for around 40 minutes (in each of sessions 2-9), which also includes listening to sounds through headphones.
• Provide quick symptom ratings of their tinnitus and its loudness before and after the electrical stimulation session. (sessions 2-9)

The first session may take up to 2 hours, and other sessions last around 1 hour each. The exact timing of the sessions can be negotiated with the research team to suit their schedule as far as possible. Weekday, evening and weekend appointments are all possible.

Separately to these sessions, we provide a copy of their personalised sound files to take home, and encourage you to listen to these for up to 60 minutes per day.

We will also contact them 6 months after the onset of their tinnitus to ask for them to report their current tinnitus symptoms, in the form of a questionnaire. This can be completed online, and does not require another visit.

Inclusion criteria

• The presence of tinnitus (persistent sound heard in one or both ears that is not coming from an external sound source or actual sounds being generated inside your body such as turbulent blood flow), which has persisted for at least 3 days, and began within the last 8 weeks. You do not need to be aware of the tinnitus all the time, but it must be persistent in the sense that is can always hear it if you listen out for it, and there is not enough other sounds around to mask it.
• Age 18 or over
• The ability to make and communicate an informed choice about whether to take part in the study
• The ability to sit still and comfortably in a comfortable chair for around 1 hour at a time.

Exclusion criteria

• Tinnitus due to a physical sound source in the body, such as turbulent blood flow or muscle contractions in the middle ear.
• Presence of tinnitus over a period of 8 weeks
• Severe or profound hearing loss at high frequencies in the tinnitus ear(s), such that you could not properly hear the sounds used in the study
• Any implanted electronic device, such as a pacemaker, cochlear implant, bone-anchored hearing aid, nerve stimulator, deep brain stimulator or spinal cord stimulator
• Any areas of broken skin on the parts of the scalp where tDCS is applied
• Ménière's disease
• Any abnormality of brain structure (e.g. stroke, tumour), or other neurological disorder (e.g. multiple sclerosis or epilepsy)
• The ongoing use of sedating medications, or certain other nerve- or brain-acting medications
• A current mental health condition of sufficient severity to prevent certain activities of everyday life

In addition to these criteria, the researcher might have other reasons to suspect that participation is either contraindicated, or might be unsuitable. In such cases, the researcher should discuss these concerns with the potential participant and/or a senior member of the research team. Participation should only proceed if all those involved in these discussions agree it should.

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