Auditory thresholds and sound exposure in Evangelical musicians and Symphony Orchestra of the National University of Cordoba in 2017

Abstract

Music exposure can produce temporary threshold shifts (TTS). More injurious exposures can produce permanent damage. The aim of this study was to describe the presence of TTS at Conventional and High Frequency (HF) audiometry, and sound exposure in Evangelical musicians (EG) and the Symphony Orchestra (SO) of the UNC in 2017.

The study was descriptive, correlational and longitudinal. We evaluated 22 musicians (14 SO, 8 EG) between 18 and 40 year old who signed a consent form. They had normal middle ear function and normal thresholds at conventional audiometry (250-8000 Hz) and were selected by a convenience method. Exclusion criteria were previous hearing pathology and exposure to occupational and recreational noise. Audiometric thresholds (AT) were measured in a mobile audiometric booth, HF audiometry evaluated from 9000 to 16000 Hz. AT were measured with 3-dB steps, before and immediately after a one-hour practice session. AT ≤18 dBHL were considered normal. Music exposure was measured frontally and laterally with microphone, amplifier, recorder and calibrator. Four practice sessions were measured in SO and one in EG. We described the difference between LAeq-LZeq for the predominance of medium-high or low frequencies. To compare TTS between groups and AT, we applied Wilcoxon and Mann-Whitney U tests, respectively.

There was significant difference (p<0.05) in both ears of each group in most frequencies. In SO, both ears showed TTS at 12500 Hz; AT were >18 dBHL in both instances at 16000 Hz. In EG, the left ear showed TTS at 250 and at 12500 Hz; AT were >18 dBHL in both instances at 14000 and at 16000 Hz and only post-test at 12500 Hz. The right ear showed TTS at 16000 Hz with AT >18 dBHL post-test. There were no significant differences in TTS between groups. The exposure level was 75,83 dB LAeq and 79,45 dB LZeq at SO; and 93,70 dB LAeq and 101,50 dB LZeq at EG. Exposure to medium-high frequencies predominated in both groups.

The EG was exposed to greater levels and presented greater TTS in both ears. HF audiometry is essential for early detection of musicians with vulnerable ears, prevention of permanent damage and hearing conservation programs.