Therefore, we used a rather strict criterion for “normal hearing”, and more specific criteria for the degree of the noise notch. The following audiogram categorization was applied to the audiometric thresholds per ear: Normal hearing (N): hearing threshold levels better than or equal to 15dB HL at all measured frequencies (i.e. 0.5, 1, 2, 3, 4, 6, 8 kHz). Notch moderate (NM): maximum threshold level of 3, 4, and 6 kHz between 15 and 20 dB poorer than the pure-tone average of thresholds at 0.5, 1 and 2 kHz and at least 10 dB poorer than the threshold
level at 8 kHz. This is similar to Niskar et al. (2001) criterion of a noise notch in adolescents. Notch profound (NP): similar to NM, but maximum threshold level of 3, 4, 6 kHz at least 25 dB poorer than the pure-tone
Selleckchem Fosbretabulin average of thresholds at 0.5, 1 and 2 kHz. Sloping loss (SL): GDC 0032 maximum threshold level of 3, 4, 6 kHz at least 5 dB poorer than the pure-tone average of thresholds at 0.5, 1 and 2 kHz and threshold level at 8 kHz at least 5 dB poorer than the maximum threshold level at 3, 4, and 6 kHz. Flat loss (FL): audiograms which do not fall into the above mentioned categories, with no hearing thresholds exceeding 30dB at all measured frequencies. Rest (R): all audiograms that do not match the E1 Activating inhibitor characteristics of the above described categories. The corresponding average audiograms are shown in Fig. 1. The average audiogram in the group “Rest” turned out to have a steeply sloping curve. Most ears fell in the “Normal hearing” category (230 ears, 48%). The other ears were approximately equally divided over the other categories Y-27632 2HCl (NM = 53 ears, 11%, NP = 41 ears, 9%, SL = 64 ears, 13%, FL = 57 ears, 12%, R = 35 ears, 7%). If present, notches were mostly found at 6 kHz. Fig. 1 Musicians average audiograms according to the criteria for normal hearing (N), notch moderate (NM), notch profound (NP), sloping loss (SL), flat loss (FL), and a rest group (R) In the
“Normal hearing” category the average age of the ears was lowest (39.7 years), while it was highest in the “Sloping loss” category (52.2 years). For the category “Notch profound” (48.8 years) it was higher than for the category “Notch moderate” (45.1 years). A direct comparison of the distribution of audiometric categories across instruments groups could only be done with some caution, as there were large variations in the number of musicians in the instrument subgroups. However, when considering only the large groups, HS, LS, WW and BW, 40–52% of each of these groups fell into the audiogram category “Normal Hearing”. The percentages did not differ significantly (χ 2(3) = 2, p = 0.57). Hearing loss with sloping curves (SL) was found less among the brass wind players (2 ears, 3%) than in the other groups (HS = 28 ears, 14%, LS = 16 ears, 20%, and WW = 13 ears, 13%, χ 2(3) = 11.9, p = 0.007).