Good vibrations: A proof-of-concept study of the preferred temporal characteristics in surf-like sounds for tinnitus therapy

A common audiological method of tinnitus management is to reduce tinnitus audibility by masking. To be effective, masking sounds need to be comfortable for long periods of time. Nature sounds, such as ocean waves or surf sounds, have been suggested to be effective for this reason. Natural or simulated surf sounds are typified by rhythmic oscillations in intensity. There are established asymmetric behavioural and physiological responses to oscillatory sounds that are ramped (gradually increase in intensity then decrease rapidly) versus damped (increase rapidly then decrease gradually over time). Ramped sounds engage attention while damped sounds are more comfortable. The aim of this study was to determine if such asymmetries in response are also translated to tinnitus masking. Two experiments were undertaken with groups of 10 tinnitus sufferers. In Part 1, an experimental round-robin tournament method was used along with rating scales to compare preferences among four recordings of natural surf sounds. In Part 2, a round-robin tournament comparing nine simulated surf sounds was used. Results indicated a preference for damped sounds over ramped sounds. Slower oscillations (rise and decay times of 5–8 seconds) were preferred to faster oscillations (rise and decay times of 2 seconds). The asymmetry in short-term tinnitus masking response to ramped and damped sounds is consistent with existing psychoacoustic research. The potential clinical use of oscillatory sounds and mechanisms underpinning observations are discussed.