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The use of personal hearing protection in hostile territory and the effect of health promotion activity: advice falling upon deaf ears
  1. Gareth H Jones1 and
  2. C R Pearson2
  1. 1Department of Otolaryngology Head and Neck Surgery, Fairfield General Hospital, Bury, UK
  2. 2Defence Audiology Service, Institute of Naval Medicine, Gosport, Hampshire UK
  1. Correspondence to Surg Cdr C R Pearson, Defence Audiology Service, Institute of Naval Medicine, Crescent Rd, Gosport, Hampshire PO12 2DL, UK; chris.pearson{at}ent.co.uk

Abstract

Introduction Noise-induced hearing loss is a significant cause of morbidity among serving soldiers despite provision of a range of personal hearing protection (PHP) and education and training. It appears that soldiers are choosing to forego PHP. This audit aimed to evaluate the effect of health promotion activity on the use of hearing protection in hostile territory.

Method 46 dismounted infantry soldiers operating out of a forward operating base in Afghanistan during Op HERRICK 17 were directly observed in order to determine the rate of wearing PHP before and after health promotion activity.

Results In the initial phase, 39% of soldiers (range 16–74%) wore PHP in at least one ear, but following health promotion activity the rate fell to 12% (range 9–14%).

Conclusions The reduction in the wearing of PHP appears to have been because the perceived diminished threat of enemy contact was outweighed by any benefit of health promotion activity. Reasons for poor compliance were not investigated, but it appears that behavioural factors, and specifically, leadership at the smallest unit level, are important. These should be investigated and considered in the development of future PHP.

  • Afghan war, 2001 -
  • Choice behavior
  • Hearing loss, noise-induced
  • Ear protective devices
  • Management audit

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Key messages

  • Even though noise-induced hearing loss may be prevented by wearing personal hearing protection, rates of wearing it varied from 9% to 74%.

  • Local risk assessment appears to be more influential than both formal and informal health promotion activities.

  • Further study is required into the behavioural factors that affect compliance rates.

Introduction

Noise-induced hearing loss (NIHL) is one of the most significant health problems among soldiers. It was the third commonest primary care evacuation category in 2009–2010 (26 out of 387 primary care patients),1 and it accounts for significant numbers of medical discharges from all three services, especially the Army and Naval Service, which includes the Royal Marines: 135 and 18 personnel were discharged from each Service, respectively, with the principal cause of hearing loss in the financial year 2013/2014.2

The hierarchy of controls (elimination, substitution, engineering controls, administrative controls, personal protective controls and equipment),3 which is widely applicable in industry, has limited use in the military context. In practical terms, the prevention of NIHL relies almost exclusively on the attenuation that may be provided by various forms of personal hearing protection (PHP): except in the case of the very loudest weapons, PHP reduces exposure to a safe level provided that it is worn correctly. In theory, therefore, hearing loss caused by exposure to noise on the battlefield or on exercise firing ranges is largely avoidable.

The requirement for employers to protect their personnel from the harmful effects of noise is enshrined in law as the Control of Noise at Work Regulations 2005 (CNWR).4 If, as is the case with nearly all modern weapons, the ‘upper exposure action value’ (which in the case of impulse noise is 137 dB(C)) is exceeded, PHP must be provided and the employer is obliged to ensure that it is worn. The Army complies with these obligations by providing the PHP described below and by mandating its use by dismounted patrols outside their static location in Standard Operating Procedures (SOP).5

The wearing of PHP on the battlefield becomes problematic if it causes situational awareness to be lost.6 In the modern era, the Combat Arms Ear Plug (CAEP) (3M, Minnesota, USA) and Personal Interfaced Hearing Protection (PIHP)7 have been introduced to overcome this problem. E-A-R (3M, Minnesota, USA) foam ear plugs have also been made widely available.

In addition to mandating the provision of PHP, CNWR also obliges an employer to provide “suitable and sufficient information, instruction and training”, which covers among others things the risks arising from exposure to noise and the use of PHP. At the time of this audit, the Army complied with this obligation by issuing a DVD and information leaflet8 ,9 as part of pre-deployment training.

Although responsibility for these statutory obligations rests with the Chain of Command, force health protection (FHP) is an element of Army Medical Services Core Doctrine10 and members of the AMS have a duty not only to undertake health promotion but also to monitor compliance with FHP measures. A general duties medical officer (GDMO) who is serving with an operationally deployed unit may contribute by undertaking health promotion in an informal setting.

It was suspected that PHP (of any type) was not being worn as mandated because of the high incidence of NIHL. Interviews have revealed that some soldiers admit to displacing one cup of their ear defenders on the ranges in order to be able to hear commands11 and the uptake of PIHP in an earlier phase of Op HERRICK investigated by questionnaire was found to be low,7 but this work is unique in describing compliance rates based upon direct observation.

Because the only study that describes the effect of follow-up training failed to demonstrate any benefit from it,12 there was no benchmark against which to compare the health promotion activity.

Method

This audit was conducted from a forward operating base (FOB) in Afghanistan during Op HERRICK 17 on a study population of 46 dismounted infantry soldiers who made up approximately 40% of the personnel in the unit and who patrolled in four ‘multiples’ of approximately 12 personnel.

The use of PHP by each of the four infantry multiples on three foot patrols was observed by the accompanying GDMO or Combat Medical Technicians over a period of 1 week. Data collection was performed discretely in order to reduce the possibility that subjects might be influenced by the audit and there was deliberately no intervention when PHP was not in place. The data collected were the number in each patrol, the type of PHP worn (PIHP, CAEP, E-A-R or none) and whether worn in one or both ears. The required standard was that 100% of personnel were to wear PHP on every occasion when they were patrolling outside their static location.

During the following week, small group health promotion sessions were delivered, typically including four or five soldiers, focusing on the causes and implications of hearing loss as well as the benefits of using the available PHP. A demonstration of the PIHP (commonly known as ‘phips’) system in conjunction with a personal role radio was included. Two weeks later repeat data collection was undertaken in the same manner, noting that Multiple 2 had been disbanded and the soldiers distributed among the other multiples.

Data were analysed using the χ2 test in Excel (Microsoft Corporation, Redmond, USA). In the absence of any factors that required ethical approval,13 no application was made to MODREC.

Results

The baseline observations (Table 1) show that CAEP was the most popular form of PHP and was the only form of PHP worn by two of the four multiples. Unilateral PHP was worn on only three occasions out of a total of 138.

Table 1

Baseline observations

Compliance after the health promotion activity (Table 2) failed to show the expected improvement in the use of PHP: in fact, the post-education data show a significant deterioration (39% to 12%, χ2=22.397, p<0.001), which was most marked in Multiple 4 that had had the best rate previously.

Table 2

Post-education observations

Discussion

This audit has shown that the majority of soldiers in a single FOB failed to wear PHP contrary to SOP and small group health promotion sessions failed to improve compliance. The austere and transient conditions in which the audit was conducted limited what could be achieved, and this work is presented as no more than an initial study. Although no attempt was made to identify the reasons for non-compliance, some conclusions may be drawn.

The low compliance rates were not due to the failure on the part of the Army to supply suitable PHP. Every soldier had been provided with PIHP. Replacement electronics were available, and although it was not possible to issue replacement inserts, each soldier had been issued with a spare pair. Supplies of the alternative CAEP and E-A-R plugs were made widely available. Likewise, this was not due to the failure on the part of the Army to provide information, instruction and training even if it was disregarded.

It has been suggested that personnel may be dissuaded from wearing PHP for fear of being seen as ‘sissy or effeminate’,14 but such a simplistic viewpoint was conjectural and is outdated. At one time it was assumed that soldiers on sentry duty or on patrol in hostile territory would be at risk of injury in an ambush were they not able to hear a warning sign such as the snapping of a twig, rustling of leaves or the movement of a stone; these sound signs, however, suggest the enemy is far too close.

The question “What does a soldier need to be able to hear?” is the subject of ongoing investigation, but recently published work15 has shown that the answer is complex: there is not only a need to be able to communicate effectively, but also to locate threats—soldiers describe the reasonable and understandable sentiment “Better off deaf than dead!” Although both CAEP and PIHP are designed to transmit (and in the case of the latter, potentially amplify) quiet sounds in the environment, it may be inferred that many troops do not wear PHP because they perceive that it poses a threat to their safety.

Helmet, body armour and goggles are intended to protect troops from hostile action that may occur suddenly and without warning; PHP is different in that it protects troops from the injurious effects of their own weapons and so the likelihood of discharging a weapon, and presumably the decision whether or not to wear PHP, will vary according to the type of patrol being undertaken (seek and destroy compared with boundary security).

The onset of a permanent threshold shift due to exposure to excessive noise is insidious; disability does not occur until, after repeated exposure, the ‘speech frequencies’ of 1, 2 and 3 kHz are affected.16 The absence of any obvious injury in the initial stages may lead troops to disregard the protection of their ears in favour of the much more immediate desire to protect life and limb.

It appears that the soldiers decided for themselves that PHP was not required when the risk of contact fell during the patrols of the second phase that had become shorter in both distance and time, but it is not clear whether the decisions were made on the basis of risk assessment by the individual commanders of the multiples or one that was made by each multiple acting collectively.

The greater use of PHP by Multiple 4 than their comrades was probably not a chance occurrence. All of the multiples belonged to the same unit, worked closely together, had the same access to PHP, performed identical tasks and were subject to the same SOP. This suggests that if the circumstances are right, soldiers will wear PHP. In the absence of data concerning their reasons, this difference is not explained, but it is possible that individual leadership at the senior NCO or junior officer level is important.

Soldiers’ lack of confidence in PHP may be because it does truly impair their ability to hear what they need to be able to hear; alternatively, the perception that it causes a significant impairment may be unfounded. Further research is required to distinguish between the two possibilities, as the solution to the former will be primarily a technical one, whereas a behavioural approach is needed for the latter. Whichever is the case, this audit shows that despite all the efforts to provide and require the use of PHP that is designed to allow situational awareness to be maintained, personnel remain reluctant to wear it.

The decline in the use of PHP after the period of education is disappointing, and the authors would like to think that it was not a reflection of the quality of the educational intervention. In an ideal world, the circumstances in each phase of the audit would have been carefully controlled in order to avoid bias, but observations were made in the field and under austere conditions that necessarily changed from day to day. Because operational circumstances appear to have had the largest effect upon compliance, it has not been possible to draw any conclusions as to the effectiveness, or otherwise, of the small group health promotion activities.

In a review of interventions to prevent occupational NIHL,17 the evidence for the success of ‘hearing loss prevention programs’ was disappointing and with hindsight it may have been naive to expect the health promotion activity to have a substantial effect. The key to the elimination of NIHL among soldiers must be a greater understanding of why they choose to wear PHP or not and any new system must not only provide adequate attenuation, but also be acceptable; only then will it be possible to implement the cultural change that is needed to address the problem of NIHL.

Conclusions

The initial rate of PHP use in accordance with the SOP was 39%, and if this finding is typical of dismounted infantry units, it goes some way to explaining the failings in the Army’s hearing conservation programme. Rates of wearing hearing PHP were from 9% to 74% and varied between units and changed as the circumstances changed. It appears that some form of risk assessment was taking place, and it is possible that the conduct of leaders at the senior NCO or junior officer level is an important determining factor. Their engagement in the hearing conservation programme is essential.

Both formal instruction and training in hearing conservation, and informal health promotion activity failed to achieve satisfactory levels of compliance with SOP, and the reasons for this are unclear and require further study. The lack of acceptability of PHP may be due to technical or behavioural factors, or a combination of the two. The provision of improved PHP requires further study in this field.

References

Footnotes

  • Contributors Both authors contributed to the study design and to the report. The first author collected the data and undertook the intervention, and acts as guarantor.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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