Sound therapy (masking) in the management of tinnitus in adults

This is an update of a Cochrane Review first published in The Cochrane Library in Issue 12, 2010.Tinnitus is described as the perception of sound or noise in the absence of real acoustic stimulation. Numerous management strategies have been tried for this potentially debilitating, heterogeneous symptom. External noise has been used as a management tool for tinnitus, in different capacities and with different philosophical intent, for over a century.

To assess the effectiveness of sound-creating devices (including hearing aids) in the management of tinnitus in adults. Primary outcome measures were changes in the loudness or severity of tinnitus and/or impact on quality of life. Secondary outcome measures were change in pure-tone auditory thresholds and adverse effects of treatment.

We searched the Cochrane ENT Group Trials Register; CENTRAL; PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 8 February 2012.

Prospective randomised controlled trials recruiting adults with persistent, distressing, subjective tinnitus of any aetiology in which the management strategy included maskers, noise-generating device and/or hearing aids, used either as the sole management tool or in combination with other strategies, including counselling.

Two authors independently examined the 387 search results to identify studies for inclusion in the review, of which 33 were potentially relevant. The update searches in 2012 retrieved no further potentially relevant studies. Both authors extracted data independently.

Six trials (553 participants) are included in this review. Studies were varied in design, with significant heterogeneity in the evaluation of subjective tinnitus perception, with different scores, scales, tests and questionnaires as well as variance in the outcome measures used to assess the improvement in tinnitus sensation/quality of life. This precluded meta-analysis of the data. There was no long-term follow-up. We assessed the risk of bias as medium in three and high in three studies. Following analysis of the data, no significant change was seen in the loudness of tinnitus or the overall severity of tinnitus following the use of sound therapy compared to other interventions such as patient education, 'relaxation techniques', 'tinnitus coping strategies', counselling, 'tinnitus retraining' and exposure to environmental sounds. No side effects or significant morbidity were reported from the use of sound-creating devices.

The limited data from the included studies failed to show strong evidence of the efficacy of sound therapy in tinnitus management. The absence of conclusive evidence should not be interpreted as evidence of lack of effectiveness. The lack of quality research in this area, in addition to the common use of combined approaches (hearing therapy plus counselling) in the management of tinnitus are, in part, responsible for the lack of conclusive evidence. Other combined forms of management, such as tinnitus retraining therapy, have been subject to a Cochrane Review. Optimal management may involve multiple strategies.