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Initially, individuals responded to an interview protocol with their personal, clinical and occupational data (anamnesis). Acoustic immittance measurements were then made, only in order to rule out middle ear alterations, followed by tonal audiometry and otoacoustic emissions. Once met the initial selection criteria, the individual subsequently underwent speech recognition testing, namely the LSP test. The LSP test consists of a list of 25 sentences, plus another seven lists with ten sentences and a noise with speech spectrum. The sentences and the noise are recorded on a CD, in independent channels, allowing their presentation in both silence and noise.
In the tinnitus group, psychoacoustic measurements were taken of tinnitus (frequency and intensity) and the level of
Tinnitus and speech in noise annoyance from tinnitus was measured by means of the Tinnitus Handicap Inventory (THI).
Sentence recognition thresholds in noise (SRTN) were obtained using the LSP test. The output of each channel was calibrated using the VU-meter on the audiometer, before testing started. The 1000 Hz tone, present in the same channel as that of the CD on which the sentences were recorded, as well as the masking noise present in the other channel, were set to zero-level. SRTN measurements were taken from each ear, separately, with the use of earphones, and the two stimuli (speech and noise) were presented ipsilaterally.
Testing was conducted with two types of noise: with the noise on the CD, as proposed by the author, and also with the speech shaped noise (SN), contained in and calibrated with the audiometer used. Calibration was performed in accordance with ISO-8253.
The application of the material was performed according to the criteria proposed by the author of the test, by employing the procedure referred to as “adaptive sequential or ascending-descending strategy”, which allows to determine the speech recognition threshold, i.e. the level necessary for the individual to correctly identify around 50% of speech stimuli presented in a given signal/noise condition. This procedure was used for measuring sentence recognition in noise, both with the noise on CD and speech noise, both of whose intensities were maintained constant at 65 dB HL.