Evaluation of hearing with audiometry and transient evoked otoacoustic emission tests in orchestra musicians

Professional orchestra musicians have consisitently been exposed to 79-98 dB sound intensity of music occupationally during rehearsal and concerts. The sound intensity that orchestra professionals exposed can reach at levels that can damage the inner ear depending on the place and the played instrument of the musician. Aim of our study is detailed investigation of hearing of orchestra musicians by audiometry, transient evoked otoacoustic emission (TEOAE), and contralateral supression test. A total of 60 individuals, including 30 orchestra musicians and 30 people who have not been involved in music and who have not been exposed to constant and/or instant noise as a control. After hearing threshold measurements, assessment of both gropus' evoked otoacoustic emission test was measured in two-stage. Firstly, orchestra musicians and the controlls were measured by TEOAE test prior to contralateral acoustic stimulation (CAS). Afterwards, 70 dB narrow band CAS was applied and measured by TEOAE test simultaneously. Age average of orchestra musicians (OM) is 36.83±6.3 and control goup is 35.83±6.8 and no statistically significant difference was (p=0.56). Statistically significant differences were found only for pure sound hearing thresholds of OM and control groups at 2000 Hz in the right ear and 16000 Hz in the left ear. TEOAE responses from the orchestra musicians were found to be relatively lower than those in control group for all frequencies. Lower emission levels were observed at 1000 Hz, 2800 Hz, and 4000 Hz frequencies while applying contralateral acoustic stimulus in orchestra musicians group and the difference is statistically significant (p<0.05). No statistically significant difference was found for the emission levels at 1400 Hz and 2000 Hz frequencies. When TEOAE measurement results applied with and without CAS are compared, statistically significant decreases in emission levels were found for all frequencies, except 4000Hz. More contralateral supression were found in control group than OM at 1000 Hz and 2000 Hz frequencies but no significant difference was found for other frequencies. Decrease in TEOAE levels was estimated as the rehearsal time of the orchestra musicians increases. No difference was observed in contralateral supression levels. As a result of this study, even though orchestra musicians are exposed to louder sound, their pure sound hearing thresholds are better than expected, whereas decrease in their TEOAE levels indicates that pure sound audiometry may not be sufficient in early diagnosis of hearing loss by niose. Difference in suppression levels of both groups, except for 2 frequencies, shows that noise affect the hearing in inner ear, but no clear effect on auditory efferent system