Jonathan Bevan v Ministry of Defence

Acoustic shock requires proof of a defined acoustic incident, ear symptoms beginning immediately or shortly afterwards, symptoms outside normal physiological or startle responses, and symptoms experienced in or arising from the exposed ear. Psychological overlay may affect disability but does not displace those diagnostic criteria.

Where exposure consists of regular, repetitive and broadly predictable noise, without a memorable acoustic event or a sufficiently close temporal link to symptoms, the criteria are not met. Bilateral tinnitus will not ordinarily satisfy the exposed-ear requirement where the exposure was unilateral, unless the tinnitus is overwhelming. If acoustic shock, noise-induced hearing loss and acoustic trauma are not established, consequential psychological or non-organic hearing loss is not attributable to the negligent exposure.

The claimant, a serving soldier, alleged that negligent exposure to noise while testing Ajax armoured vehicles caused tinnitus, hearing loss and consequential psychological injury resulting in non-organic hearing loss. Breach of duty was admitted, but causation and, if necessary, quantum remained in issue.

The claim initially referred to noise-induced hearing loss but by trial relied principally on acoustic shock. The court considered the timing and nature of the claimant’s symptoms, the character of the noise exposure, expert evidence, and the diagnostic criteria for acoustic shock. The central issue was whether the claimant had suffered an acoustic-shock injury caused by the admitted exposure.

1. Claim dismissed. The claimant did not establish that the admitted negligent noise exposure caused his tinnitus, hearing loss or consequential psychological injury.
2. The court accepted the Grindleford Criteria, described in Parker 2020, as the best and only available guidelines for determining acoustic shock. They require: (i) a defined acoustic incident; (ii) ear symptoms beginning immediately or shortly afterwards; (iii) symptoms outside physiological or startle responses; and (iv) symptoms experienced in or arising from the exposed ear. Psychological overlay may affect the degree of disability but is not a separate diagnostic requirement.
3. The exposure in the Ajax vehicles was regular, repetitive and broadly predictable. It involved recurring alarms and general vehicle noise, but no memorable or unusual acoustic event. The absence of such an event meant that the temporal requirement could not be satisfied.
4. The claimant’s tinnitus arose after December 2020 and before March 2021, after the relevant vehicle exposure had ceased. The tinnitus was bilateral and severe, but not overwhelming. It therefore did not arise from the exposed right ear within the fourth criterion.
5. There was no noise-induced hearing loss because the audiograms lacked the relevant notch or bulge. Nor was there acoustic trauma. The December 2020 medical letter recorded treatment as if acute acoustic trauma existed, but did not amount to a diagnosis.
6. Since no qualifying acoustic-shock injury, noise-induced hearing loss or acoustic trauma was established, the tinnitus and any hearing loss were not caused by the negligent exposure. Any conversion disorder or functional neurological disorder producing non-organic hearing loss was consequently not attributable to it. Quantum and counterfactual findings were not addressed by agreement.