TEO - Ready to go into Orbit!

BTW - The Plantronics marketing shit above is exactly that SHIT. There is no definition for Acoustic Shock yet Plantronics appear to have one. Acoustic Starle is a reation of muscles in the inner ear which may lead to Acoustic Shock which can lead to Pain, Dizziness, Nausea etc.

Startle

Sudden, unexpected sound
Seems loud compared with background
- but does not need to be very loud
- 50dB may be sufficient

There are 2 small muscles. When you hear a loud noise stapedius contracts to reduce the movement in the stapes, the last bone in the chain. It acts as a damper, reducing the energy transmitted to the cochlea. The tensor tympani acts to damp the eardrum, but not specifically in response to loud noise. It's not know why, but it reacts to startle – that can be anything sudden and unexpected, including noise. If it is sudden noise then it needs far less loudness to get a tensor tympani response than to cause stapedius to respond. A sudden contraction of tensor tympani at the same time as a moderately loud sound is heard can push a pressure wave through the cochlea, and on into the balance organs of the inner ear
Acoustic shock seems to follow a startle response. Startled by a sudden noise that seems loud to the worker compared to normal headset levels, but which doesn’t have to be very loud - just loud enough to provoke a startle reaction. In a quiet room that could be as low as 50dB - a noise level that is lower than ambient noise levels in most call centres.
Acoustic Shock seems to be triggered by a startle response, which needs a noise which is perceived as loud, but which does not need to be anywhere near the sound level required to cause acoustic trauma. The immediate effects include discomfort, muffled hearing and feeling unwell. Later there may be tinnitus and altered hearing. Some go on to have anxiety and depression.
Reducing peak noise exposure may well reduce the risk of triggering acoustic shock, but it cannot prevent a startle response in a susceptible individual. There may well be fewer incidents, but there will still be some.
Mental health issues are important when it comes to triggering acoustic shock. The startle response is modified by personality; some people are much more difficult to startle than others. On the other hand, people who are anxious, or who are waiting for bad things to happen (hypervigilance) have a much greater sensitivity to startle.
They are more likely to suffer acoustic shock, and Australian research shows that if workers have had a previous acoustic shock, subsequent shocks result in worse and longer-lasting symptoms. If somebody is anxious following a previous shock, they are likely to be more easily startled, and more likely to suffer another acoustic shock.

And Plantronics are basing their whole marketing on this - SCANDALOUS