Phase-shift treatment for tinnitus of cochlear origin.

Phase-shift treatment is a new tinnitus therapy that aims at sound cancelling. This technique is based on a theory advocating that the induction of a sound wave with a 180 degrees phase-shift compared to the sound experienced by the patient could result in sound cancelling, likely by negation of the cortical perception of tinnitus or residual inhibition, which can be partial or complete. The aim of our study is to compare the effect of phase-shifting generated by the tinnitus phase-out device between pure tone tinnitus patients (PTP) and narrow band noise tinnitus patients (NBNP). In present comparative study, we explore the effects of phase-shifting during 6 weeks of phase-out therapy in PTP and NBNP. Thirty-five tinnitus patients were included in the study. Twenty-one patients had pure tone tinnitus and 14 patients had narrow band noise tinnitus. The effects on tinnitus were assessed using three separate visual analogue scales (VAS), the tinnitus questionnaire, the hyperacusis questionnaire, the Beck depression inventory, a categorical scale and audiometric measurements. While no differences in VAS were seen after therapy in NBNP, tinnitus increase could be demonstrated in PTP. This increase could be demonstrated for tinnitus loudness (p = 0.002) and tinnitus annoyance (p = 0.014). In conclusion, implementation of phase-shifting did not lead to significant sound cancelling. Our results are discussed and compared to previous studies investigating the effects of phase-out in tinnitus patients.