‘Acoustic shock’
Reviewed by Madhup K Chaurasia

Development of hearing loss due to traditional and steady state noise in working environments has well defined medical, physical and legal implications in the present times. Organisations not complying with ‘Noise at Work Regulations 1989’ are liable for compensation if their workers develop noise-induced hearing loss (NIHL). However, exposure to unexpected noise at levels much lower than those which are expected to cause NIHL, and even noise attenuated by headphones, can result in what is more recently recognised as ‘acoustic shock’. The article provides an interesting reading into the characteristics of ‘acoustic shock’. The condition can result from unexpected acoustic incidents such as involving use of telephones or headsets. It is postulated that the acoustic incident can induce tensor tympani spasm, trigeminal modulation, and central disruption of auditory processing. The audiovestibular, neurophysiological and psychological symptoms that result are otalgia, tinnitus, hearing loss, hyperacusis, phonophobia, vertigo, numbness, burning sensation and even some ear discharge. This is an entity in itself, alongside the phenomenon of ‘acoustic startle’ which can develop with non-acoustic incidents, for example a blast of wind into the eyes. Diagnostic criteria for this condition have been defined. Pre-existing biopsychosocial factors have been considered as predisposing factors to this condition. Those most at risk are middle-aged females with pre-existing neuropsychiatric disorders. The possibility of this condition existing may have implications in claims where typical conditions and factors responsible for noise damage may not be evident. In this context, an interesting court claim, based on this concept has been described where the defendant faced a massive pay-out.

Acoustic shock: an update review.
Parker WAE, Parker VL, Parker G, Parker AJ.
J LARYNGOL OTOL
2021;134:848-53.