Spatial masking: Development and testing of a new tinnitus assistive technology.

Masking is widely used in the management of tinnitus, however, masking at the perceived spatial location of tinnitus has not been investigated. This article examines the development of a method for the spatial masking of tinnitus. This report consists of three studies: Study I is a proof of concept study comparing customized spatial masking to conventional bilateral masking; Study II is a prototype evaluation in which the spatial masking paradigm was compared to a bilaterally equal masker using iPods connected to hearing aids in a 4-week cross-over trial; and Study III is a 4-month crossover pilot study-using prototype hearing aid-based maskers, and in which three-dimensional (3D) masking (2 months) was compared to a Tinnitus Retraining Therapy (2 months). There was a preference for the 3D masking stimulus across all three studies. Individual changes in the Tinnitus Handicap Inventory (THI) after 2 weeks of trial (Study II) and Tinnitus Functional Index (TFI) after 2 months of trial (Study III) were observed without large group differences. The spatial masking concept was piloted successfully. The qualitative and quantitative results obtained indicate directions for future clinical trials and therapy development. This study indicates that spatial masking of tinnitus is feasible, of benefit to many participants, and warrants further trials.