Abstract Introduction Tinnitus and associated handicap related to acoustic trauma sequelae have never been assessed in the French artillery. Although impulsive noise exposure to firearms and canons are thought to increase prevalence of tinnitus among soldiers, recent studies demonstrating this fact are missing. Materials and Methods Here, a representative sample of 389 soldiers from an operational mountain artillery regiment was surveyed. Soldiers personally concerned by tinnitus were invited to fill in a questionnaire. We assessed tinnitus and the associated handicap using a French translation of the Tinnitus Handicap Inventory (THI). Questions about attention/concentration problems, impaired speech hearing and understanding, sleep disorders, social and familial tension, irritability, depression, and tiredness as linked to tinnitus were the core of the questionnaire. Results Soldiers that completed the THI (n = 73, 19%) had a mean THI score of 18 ± 17, this mean score corresponded to a mild handicap. At this grade, tinnitus should be easily masked and should not interfere with daily activities. The percentage of soldiers concerned by tinnitus was slightly higher in the older age class, but there was no significant difference of THI scores between the different age classes. The most reported handicaps were attention/concentration problems, impaired speech hearing, and understanding. Among the THI fillers, eight soldiers (11%) had THI scores >36, indicating a moderate to severe handicap. Conclusion Despite a mild tinnitus handicap, the percentage of people concerned by tinnitus in this regiment is higher (19%) than that in the estimated percentage of general population of European countries (about 10%). It should be of interest to replicate this type of study from other regiments and from other countries. Education and good fitting of hearing protection for prevention of acoustic trauma sequelae should still be encouraged. INTRODUCTION Intense noise exposure to firearms is important in operational regiments. In artillery and, in particular, in the French mountain artillery, the use of the French gun FAMAS and canons in mountainous environment, full of reverberation, particularly exposes this population to high acoustic pressure levels. In France, we have no reports assessing specifically, in regiments, tinnitus, and the associated handicap. As the case incidence of acoustic trauma (AAT) in France in the last few years is about 1,000 cases per year (epidemiological surveillance), regiments could have post-traumatic tinnitus as sequelae. Consequences have never been assessed. However, bearing in mind the importance of hearing and understanding under fire, bothersome tinnitus sounds could disturb soldier’s missions.1,2,3,4 The tinnitus mechanisms are still unclear. AAT tinnitus was thought to be simple, but it appears that it is not. Indeed, it was thought that AAT tinnitus was the direct consequence of auditory cell damage, leading to hearing loss and subsequently triggering an aberrant cortical reorganization in the auditory cortex .5 This model, originating from animal models, is difficult to support by the clinical experience alone .6 Research work is still in progress concerning acoustic trauma tinnitus and new models are emerging, giving a wider role to the somatosensory pathway7,8 or presenting middle ear proprioception at the center of this phantom auditory perception that could be a middle ear kinesthetic illusion.9 In this brief report, we will not discuss this point but only assess the impact of tinnitus in an operational regiment using a reference questionnaire (Fig. 1) in the field of tinnitus, the Tinnitus Handicap Inventory (THI).10 Figure 1. View largeDownload slide Tinnitus Handicap Inventory (THI) questionnaire. In the study, the French version was provided (not presented). Figure 1. View largeDownload slide Tinnitus Handicap Inventory (THI) questionnaire. In the study, the French version was provided (not presented). MATERIALS and METHODS The THI French version was distributed by the employee responsible for preventing professional risks to all mountain artillery personnel present at the regiment during the main meetings of the regiments for a period of about 1 yr in 2014–2015. These meetings took place in an amphitheater. Thus, all questionnaires distributed were returned completed or not completed the same day in the amphitheater and before the end of the meeting. The study was carried out according to the basic principles of the Helsinki declaration. Each volunteer soldier should normally fill in a two-part form: the THI, if they were concerned by tinnitus (written instruction before the THI) and a questionnaire on prevention and general risks at work, but this was not mandatory, they could leave blank both questionnaires. Questionnaires were anonymous, but age was nevertheless asked as a first question. Military rank was not reported and responses to questionnaires were covered by a blank page to preserve privacy of responses. Thus, soldiers personally concerned by tinnitus could fill in the THI confidently, others not knowing which questionnaire they completed. THI is internationally used, thus enabling its utilization for further comparison with data from other countries. Despite the fact that the questionnaire was anonymous, we could not guarantee that soldiers had not minimized their handicap due to the risk of their fitness for duty being challenged. The THI score was the sum of the 25 answers where a weight of 4 was given to the answer “Yes,” a weight of 2 to the answer “Sometimes,” and a weight of 0 to the answer “No.” Thus, the range of scores was between 0 and 100, where 100 was the maximum score that could be obtained for the sum of the 25 questions. Levels of handicap are estimated as follows:11 Grade 1 – slight handicap (THI 0–16): Only heard in quiet environments, very easily masked, almost no interference with sleep or daily activities. THI score = 0 does not mean that THI is blank; it means that the option “No” is checked for the 25 questions. It also means that tinnitus is present but perceived not bothersome. Grade 2 – mild handicap (THI 18–36): Easily masked with environmental sounds but could interfere occasionally with sleep but not daily activities. Grade 3 – moderate handicap (THI 38–56): May be noticed even with background noise, although daily activities may still be performed, interferes more frequently with sleep, and tasks that need concentration. Grade 4 – severe handicap (THI 58–76): Leads to disturbed sleep patterns and can interfere with the ability to carry out a normal daily life. Grade 5 – catastrophic (THI 78–100): Ability to carry out a normal life is seriously impaired. Associated psychological problems are likely to be found in hospital or general practitioner records. Data were analyzed and processed with IBM SPSS software, version 22.0 (IBM Inc.). Mean THI score comparisons between age classes were performed with the non-parametric Kruskal–Wallis test. A p-value < 0.05 was considered statistically significant. RESULTS Population Data were collected from 389 soldiers from the French mountain artillery. This population sample was representative of the total regiment. According to administrative information, about 40% of soldiers from the regiment could not be present due to missions, training, vacation, or illness. Very few questionnaires (n = 8, 2%) were returned blank (both questionnaires). Age ranges from 18 to 52 yr and age distribution corresponds to the reality of age throughout the regiment (Fig. 2). Mean age is 28 ± 7 yr. We have considered three age classes: the 18–23 yr old (n = 123, 32%), the 24–29 yr old (n = 138, 35%), and the 30–52 yr old (n = 128, 33%) to obtain roughly an equivalent percentage of soldiers in each class. Figure 2. View largeDownload slide Age histogram in the studied population. Figure 2. View largeDownload slide Age histogram in the studied population. THI Results Seventy-three soldiers filled in the THI (73/381, 19%). The number or the percentage of responders increased with the age classes: 10% in the age class (18–23 yr), 14% in the age class (24–29 yr), and 28% in the age class (30–52 yr), respectively (Fig. 3A). Figure 3. View largeDownload slide (A) Number (top) and percentage (bottom) of soldiers in each age class concerned by tinnitus that completed the THI. (B) Histogram of THI scores in the French mountain artillery regiment (top) and box plot of THI scores in each age class (bottom), the four outliers (*) represented soldiers with severe handicaps. Figure 3. View largeDownload slide (A) Number (top) and percentage (bottom) of soldiers in each age class concerned by tinnitus that completed the THI. (B) Histogram of THI scores in the French mountain artillery regiment (top) and box plot of THI scores in each age class (bottom), the four outliers (*) represented soldiers with severe handicaps. In general, the tinnitus handicap could be considered as mild because the histogram of THI scores in this population was mostly inferior to 38 (Fig. 3B, top). Nevertheless, 11% of them had a moderate to severe handicap (six soldiers with THI > 38 and two soldiers with THI > 58). THI scores did not differ between age classes (Fig. 3B, bottom) (Kruskall–Wallis test). Detailed results of each THI question revealed that two of them (i.e., Q8 and Q19) obtained the highest score (Fig. 4). When examining the other questions, several bothersome problems seemed to emerge: attention/concentration problems, impaired speech hearing and understanding (values superior to mean + 2 SD), and, to a lesser extent, sleep disorders and tiredness (values superior to mean). In soldiers with moderate to severe handicaps (THI > 36), the mean for each question was of course elevated, peaking at Q8 and Q20 (Fig. 5). Figure 4. View largeDownload slide Detailed THI (25 items). Mean soldiers’ responses for each item. Horizontal lines indicated the mean value (full line) of items (Q8 and Q19 excluded) and mean value + 2 SD (dashed line). Figure 4. View largeDownload slide Detailed THI (25 items). Mean soldiers’ responses for each item. Horizontal lines indicated the mean value (full line) of items (Q8 and Q19 excluded) and mean value + 2 SD (dashed line). Figure 5. View largeDownload slide Detailed THI (25 items). Tinnitus soldiers with THI score > 36 (moderate to severe handicaps). Mean soldiers’ responses for each item. Figure 5. View largeDownload slide Detailed THI (25 items). Tinnitus soldiers with THI score > 36 (moderate to severe handicaps). Mean soldiers’ responses for each item. DISCUSSION The specific assessment of tinnitus and associated handicaps in French forces is totally new and, most probably, the majority of the world’s armed forces do not possess this type of data. Indeed, we found only one scientific publication from Asia in 201112 that reported the tinnitus handicap assessment by THI for 189 soldiers after 1-d shooting practice without protectors. The mean THI reported in this publication was 39.51 ± 14.87, a value that could inform us of the potential handicap if our soldiers were not protected. In reference to this publication, we are inclined to think that hearing protection (earmuffs + non-linear filter earplugs) in this artillery regiment is satisfactory. However, soldiers that seemed concerned by tinnitus represented 19% of our population with people no older than 52 yr. The prevalence of tinnitus in European countries is estimated at around 10% for the total population, 1–2% had severe handicap.13,14 Also, bearing in mind that tinnitus prevalence is mostly present in elderly people,14 we could estimate that the percentage of tinnitus in artillery is slightly higher than the general population of the same age. Here, nevertheless, the handicap is considered as mild, so apparently with minimal consequences on most daily activities. Although comparisons of tinnitus prevalence with other studies are very difficult due to different selection criteria, equivalent studies as ours, using THI scores in various world-armed forces and its branches would be of great interest for the international military medical community. Responses to Q8 and Q19 obtained the highest scores; these two questions highlighted the feeling of helplessness of soldiers when they have to deal with tinnitus, their impossibility to control it. Not many soldiers had a moderate or severe handicap; nevertheless, the medical personnel should detect them because they are more susceptible to tiredness (i.e, Q20) at least for three reasons. First, the perception of tinnitus leads them to process auditory information as a dual task (two concurrent inputs, external and internal sounds). The complexity of this sustained cognitive treatment could result in mental fatigue.15 Second, permanent threshold shifts (PTS) or temporary threshold shifts (TTS) are often present among military personnel, whose consequences are hearing and listening handicap. Auditory cell impairments together with tinnitus would lead to an additional effort to concentrate on verbal message or any auditory information. Third, tinnitus is often well heard in silent environment, in particular at night, and consequently more frequent sleep disturbance will also disturb their daily cognitive and physical abilities.16 The awareness of a possible impact of tinnitus on soldiers’ fitness for duty should encourage soldiers and their commanders to provide optimum protection of their hearing. Indeed, the old adage that “an ounce of prevention is worth a pound of cure” is a salutary reminder. In France, prevention policies to encourage proper positioning and optimal size fitting of hearing protectors by education are in progress and are still necessary to avoid development of AAT. We encourage other countries or other armed forces to assess tinnitus using the THI for further comparisons. FUNDING This study was supported by a French military grant, DGA PDH-1-SMO-3-811. The authors declare that there was no conflict of interest in this study. Acknowledgments Sincere thanks to Colonel F. Armangau, head of the “93ème RAM,” to S. Bouquet for the organization of this study, and to all soldiers of the “93ème RAM” for their collaboration in completing the questionnaire. REFERENCES 1 Andersson G : Psychological aspects of tinnitus and the application of cognitive-behavioral therapy . Clin Psychol Rev 2002 ; 22 ( 7 ): 977 – 90 . Google Scholar CrossRef Search ADS PubMed 2 Reynolds P , Gardner D , Lee R : Tinnitus and psychological morbidity: a cross-sectional study to investigate psychological morbidity in tinnitus patients and its relationship with severity of symptoms and illness perceptions . Clin Otolaryngol Allied Sci 2004 ; 29 ( 6 ): 628 – 34 . Google Scholar CrossRef Search ADS PubMed 3 Job A , Cian C , Esquivie D , et al. : Moderate variations of mood/emotional states related to alterations in cochlear otoacoustic emissions and tinnitus onset in young normal hearing subjects exposed to gun impulse noise . Hear Res 2004 ; 193 ( 1–2 ): 31 – 8 . Google Scholar CrossRef Search ADS PubMed 4 Schmitt C , Patak M , Kroner-Herwig B : Stress and the onset of sudden hearing loss and tinnitus . Int Tinnitus J 2000 ; 6 ( 1 ): 41 – 9 . Google Scholar PubMed 5 Eggermont JJ , Roberts LE : The neuroscience of tinnitus . Trends Neurosci 2004 ; 27 ( 11 ): 676 – 82 . 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This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
Military Medicine – Oxford University Press
Published: Sep 1, 2018
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