The statistical distribution of normal hearing thresholds for low-frequency tones

The statistical distribution of normal hearing thresholds for pure tones in the low-frequency (LF) region was estimated as a function of frequency, using a similar procedure to that used in an earlier work by the authors Kurakata et al., [3]. First, the distribution of individual LF thresholds was investigated using threshold measurement data. Results indicated that the threshold variation among individuals can be approximated using a normal distribution. Second, under the assumption of normality, standard deviations (SDs) of hearing threshold distributions were calculated. For that calculation, the measurement data of different studies were integrated to enhance the estimation accuracy. Finally, using the obtained SDs, the threshold distribution around the average value was presented graphically. These results illustrate the profile of our auditory sensitivity at LFs more accurately and are useful for evaluating the audibility of LF noises because they incorporate individual differences.