Acoustic shock is a world-wide phenomenon that has been increasing in line with the expansion of the contact centre industry. With the proliferation of contact centres came a dramatic increase in the use of headsets which are a major contributing factor in the incidence of acoustic shock syndrome.

Acoustic Shock Syndrome occurs when a headset user is exposed to a sudden and unexpected loud noise or high pitched sound, usually in the frequency range 1kHz - 4kHz.

It is the sudden and unexpected onset of these sounds which is the cause of acoustic shock. Using a headset increases the risk of dangerous exposure to high pitched sounds because a headset, unlike a traditional phone handpiece, cannot be dropped or quickly removed from the ear as soon as the noise is heard.

Simply being exposed to constant loud noise through a headset cannot cause acoustic shock. This may cause long term hearing damage, but not acoustic shock injury.

Examples of high-pitched tones or acoustic shrieks:

  • Incorrectly dialled fax machines.
  • Maliciously generated noises - screaming or blowing a whistle down the line.
  • Feedback or oscillations between a cordless phone and its base station.
  • Mobile phone interference.
  • Faults on the telephone line that cause loud shrieks from the Public Switched Network.
  • Callers dropping their handset on to a desktop.

Symptoms of Acoustic Shock

The typical symptoms of Acoustic Shock are:

  • Ear-ache and nausea.
  • Headaches, jaw and neck pain.
  • Hollow feeling in the ear.
  • 'Fluttering' noise in ear, leading to poor balance.
  • Burning sensation to face and head.
  • Tinnitus (ringing in the ear) and hearing degradation over time.
  • Permanent sensitivity to loud noises in general, thus affecting lifestyle.
  • Where inner ear membranes have been otherwise weakened (by ear infections or diving trauma) acoustic shock can cause tearing of the inner ear membrane.
  • Stress and apprehension about the likelihood of a recurring incident.

Affected workers may then feel hypersensitive to loud sounds that previously would have caused no problems. The fear that a shriek might reoccur lowers their threshold even further, putting them at greater risk of injury if it happens again. This is even likely to affect co-workers, who may be apprehensive about the likelihood of an incident.

The problem of Acoustic Shock is not limited to any particular telephone or headset type, or any particular telecommunications network or equipment. High pitched tones are random and often cannot be traced or prevented from recurring.