Abstract
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Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources forpublished and unpublished trials.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.
Plain language summary
Sound therapy (using amplification devices or soundgenerators) for tinnitus
Review question
Is sound therapy (using amplification devices, sound generators orboth) effective for tinnitus in adults?
Background
Tinnitus is the awareness of a sound in the ear or head without any outside source. It affects 10% to 15% of the adult population. About 20% of people with tinnitus experience symptoms that negatively affect their quality of life including sleep disturbances, difficulties with hearing and concentration, social isolation, anxiety, depression, irritation or stress. Tinnitus can be managed through education andadvice, relaxation therapy, psychological therapy, or devices that improve hearing or generate sound such as sound generators orhearing aids. Sometimes drugs are prescribed to manage problems associated with tinnitus such as sleep problems, anxiety ordepression. The purpose of this review is to evaluate the evidence from high‐quality clinical trials to work out the effects of soundtherapy (hearing aids, sound generators and combination hearing aids) on adults with tinnitus. We particularly wanted to look at the effects of sound therapy on tinnitus severity and any side effects.
Study characteristics
Our review identified eight randomised controlled trials with 590 participants in total. Seven studies looked at the effects of hearing aids, four combination hearing aids and three sound generators. Seven studies allocated participants into parallel groups and in one study participants tried each intervention in a random order. The outcomes that we looked for were severity of tinnitus symptoms, depression, anxiety, quality of life and side effects. In general, the risk of bias in the studies was unclear. There was also little or no useof blinding.
Key results
We did not find any data for our outcomes for any of our three main comparisons (comparing hearing aids, sound generators andcombination devices with a waiting list control group, placebo oreducation/information only). There were also few data for our additional comparisons (comparing these devices with each other)and it was difficult to pool (combine) the data.
Hearing aid only versus sound generator device only
One study compared patients fitted with sound generators with those fitted with hearing aids and found no difference between them in their effects on our primary outcome, tinnitus symptom severity, at 3, 6 or 12 months. 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/sound generatorswith hearing aids alone and measured tinnitus symptom severity. When we combined the data for tinnitus symptom severity we found no difference between them. The use of both types of device was again associated with a clinically significant reduction in tinnitussymptom severity.
Adverse effects were not assessed in any of the included studies.
None of the studies measured depressive symptoms or depression, anxiety symptoms or generalised anxiety, or other important outcomes of interest in this review.
Quality of evidence
Where outcomes that we were interested in for this review were reported, we assessed the quality of the evidence available as low.Using a hearing aid, sound generator or combination device might result in little or no difference in tinnitus symptom severity.
