Objective: To assess the influence on speech intelligibility of various signals used in tinnitus sound therapy.
Materials and methods: We measured, in normal hearing subjects, the intelligibility of speech in the presence of three different sound therapy signals: wide-band noise, a recording of moving water, and a combination of tones.
Results: For a given level of stimulation, speech intelligibility was worst in the presence of wide-band noise, compared with the other sound therapy signals. When the stimulation level of the three different signals was increased, speech intelligibility deteriorated more rapidly with wide-band noise, compared with the other two signals. The combination of tones had the least influence on speech intelligibility.
Conclusion: The use of different tinnitus sound therapy signals can lead to significantly different effects on the intelligibility of speech. The use of natural sound recordings or combinations of tones may provide the patient with more flexibility to change the stimulation level during treatment.