Occupational Hygiene Practice Test

Intense noise exposure initially damages the basal part of the cochlea, where high-frequency sounds are encoded. This region is most vulnerable to loud sound, so the outer hair cells here sustain damage first, leading to reduced sensitivity to high tones. On an audiogram, the classic pattern is a high-frequency notch around 4 kHz, reflecting this early high-frequency loss. If exposure continues, the damage can broaden to mid and eventually low frequencies, but the earliest and most pronounced deficit appears with high tones.