The audiogram in NIHL shows a typical notch, at 4kHz both for air and bone conduction.
It is usually symmetrical on both sides. At this stage, patient complains of
high pitched tinnitus and difficulty in day to day hearing. As the duration of noise
exposure increases, the notch deepens and also widens to involve lower and higher frequencies.
Noise-induced hearing loss is preventable. Persons who have to work at places
where noise is above 85dB(A) should have pre-employment and then annual audiogram
for early detection. Ear protectors should be used where noise levels exceed 85dB