Background

Tinnitus affects 10% to 15% of the adult population, with about 20% of these experiencing symptoms that negatively affect quality of life. In England alone there are an estimated ¾ million general practice consultations every year where the primary complaint is tinnitus, equating to a major burden on healthcare services. Clinical management strategies include education and advice, relaxationtherapy, tinnitus retraining therapy (TRT), cognitive behaviouraltherapy (CBT), sound enrichment using ear‐level sound generators orhearing aids, and drug therapies to manage co‐morbid symptoms such as insomnia, anxiety or depression. Hearing aids, soundgenerators and combination devices (amplification and soundgeneration within one device) are a component of many tinnitusmanagement programmes and together with information and advice are a first line of management in audiology departments forsomeone who has tinnitus.

Objectives

To assess the effects of sound therapy (using amplification devicesand/or sound generators) for tinnitus in adults.

Search methods

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL, via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources forpublished and unpublished trials. The date of the search was 23 July 2018.

Selection criteria

Randomised controlled trials (RCTs) recruiting adults with acute orchronic subjective idiopathic tinnitus. We included studies where the intervention involved hearing aids, sound generators or combination hearing aids and compared them to waiting list control, placebo oreducation/information only with no device. We also included studies comparing hearing aids to sound generators, combination hearing aids to hearing aids, and combination hearing aids to soundgenerators.

Data collection and analysis

We used the standard methodological procedures expected by Cochrane. Our primary outcomes were tinnitus symptom severity as measured as a global score on multi‐item tinnitus questionnaire andsignificant adverse effects as indicated by an increase in self‐reported tinnitus loudness. Our secondary outcomes were depressive symptoms, symptoms of generalised anxiety, health‐related quality of life and adverse effects associated with wearing the device such as pain, discomfort, tenderness or skin irritation, or ear infections. We used GRADE to assess the quality of evidence for each outcome; this is indicated in italics.

Main results

This review included eight studies (with a total of 590 participants). Seven studies investigated the effects of hearing aids, fourcombination hearing aids and three sound generators. Seven studies were parallel‐group RCTs and one had a cross‐over design. In general, risk of bias was unclear due to lack of detail about sequence generation and allocation concealment. There was also little or nouse of blinding.

No data for our outcomes were available for any of our three main comparisons (comparing hearing aids, sound generators andcombination devices with a waiting list control group, placebo oreducation/information only). Data for our additional comparisons (comparing these devices with each other) were also few, with limited potential for data pooling.

Hearing aid only versus sound generator device only

One study compared patients fitted with sound generators versus those fitted with hearing aids and found no difference between them in their effects on our primary outcome, tinnitus symptom severity measured with the Tinnitus Handicap Inventory (THI) at 3, 6 or 12 months (low‐quality evidence). The use of both types of device was associated with a clinically significant reduction in tinnitus symptom severity.

Combination hearing aid versus hearing aid only

Three studies compared combination hearing aids with hearing aidsand measured tinnitus symptom severity using the THI or TinnitusFunctional Index. When we pooled the data we found no difference between them (standardised mean difference ‐0.15, 95% confidence interval ‐0.52 to 0.22; three studies; 114 participants) (low‐quality evidence). The use of both types of device was again associated with a clinically significant reduction in tinnitus symptom severity.

Adverse effects were not assessed in any of the included studies.

None of the studies measured the secondary outcomes of depressive symptoms or depression, anxiety symptoms or generalised anxiety,or health‐related quality of life as measured by a validated instrument, nor the newly developed core outcomes tinnitusintrusiveness, ability to ignore, concentration, quality of sleep andsense of control.

Authors’ conclusions

There is no evidence to support the superiority of sound therapy fortinnitus over waiting list control, placebo or education/information with no device. There is insufficient evidence to support the superiority or inferiority of any of the sound therapy options (hearing aid, sound generator or combination hearing aid) over each other. The quality of evidence for the reported outcomes, assessed usingGRADE, was low. Using a combination device, hearing aid or soundgenerator might result in little or no difference in tinnitus symptom severity.

Future research into the effectiveness of sound therapy in patients with tinnitus should use rigorous methodology. Randomisation andblinding should be of the highest quality, given the subjective nature of tinnitus and the strong likelihood of a placebo response. The CONSORT statement should be used in the design and reporting of future studies. We also recommend the use of validated, patient‐centred outcome measures for research in the field of tinnitus.