Psychoacoustical tuning curves. Normative data for clinical use

This normative study presents a clinically applicable method with which to obtain Psychoacoustical Tuning Curves: data are obtained with clinical audiometers, and measurements are performed on normal-hearing non-trained volunteers. A simultaneous masking method with test frequency of 4,000 Hz was used, withmasking being incremented in 5 dB or 1 dB steps. One group of subjects was tested three times with 5 dB incrementing steps to evaluate the method's reproducibility. A second group of subjects was measured twice with 1 dB incrementing steps, to compare the reproducibility of the 1-dB step measurements, and the difference between the 1-dB step and 5-dB step measurements. All the data were evaluated as normative values. The method presented proves to have a good reproducibility. Although testing with 1-dB incrementing steps provides more accurate measurements and curves with steeper slopes, the 5-dB incrementing step method is more practicable. Interest variability evaluation indicates that differences between two measurements performed on the same person exceeding 120 Hz (2 SD) bandwidth can be interpreted as significant.