[Acute acoustic trauma]. / Akuutti meluvamma.

Acute acoustic trauma (AAT) may result from a single, intense impulse noise, or from brief exposure to strong noise. Ringing in the ear in consequence of noise exposure is the first alarm indicating that the tolerance of the inner ear has been exceeded. The ringing will be accompanied by hearing impairment, stuffiness and blocking. Other symptoms may also appear. The symptoms disappear in most people after the cessation of noise, but in some the symptoms remain persistent or permanent. Treatment options are limited.

The effect of tightened hearing protection regulations on military noise-induced tinnitus.

The objective of this study was to investigate the effect of tightened hearing protection regulations on tinnitus in the Finnish Defence Forces. The initial study group comprised 252 officers and non-commissioned officers (NCOs), of which 229 were included in the final study group. Subjective symptoms of tinnitus and audiometric test results for these officers and NCOs examined before retirement, from 1984 to 1986 (Period I), and 2003 to 2005 (Period II), were reviewed. Changes in tinnitus reports between the two time periods, during which regulations had been revised, were investigated. Prevalence of tinnitus showed a decline both in officers (from 68% to 63%) and in NCOs (from 76% to 72%) between the two study periods, in accordance with tightened hearing protection regulations. The Cox regression analysis showed a significantly decreased hazard ratio for constant or disturbing tinnitus for Period II. Tinnitus prevalence, especially constant or disturbing tinnitus, in the Finnish Defence Forces was diminished by tightened hearing protection regulations. Tinnitus might be more persistent than hearing loss and does not necessarily improve in direct relation to hearing loss after protective measures.

The effect of improved hearing protection regulations in the prevention of military noise-induced hearing loss.

CONCLUSION: Hearing protection regulations have improved the hearing test results of soldiers in the Finnish Defense Forces. OBJECTIVES: To investigate the effect of revised regulations regarding usage of hearing protectors of professional soldiers in the Finnish Defense Forces. SUBJECTS AND METHODS: The medical records of non-commissioned officers and officers examined at the Central Military Hospital ENT Department from 1984 to 1986 (Period I) and 2003 to 2005 (Period II) were reviewed. The study group comprised 252 persons. Changes in hearing between the two time periods, during which regulations were revised, were investigated. RESULTS: Hearing test results improved both in non-commissioned officers and in officers between the two study periods, in accordance with tightened hearing protection regulations. Improvement was found, especially in the high frequencies; however, the results were milder than expected, particularly in officers.

Military and leisure-time noise exposure and hearing thresholds of Finnish conscripts.

This study presents an evaluation of the total cumulative noise exposure of Finnish conscripts (N = 416) during military service. All of the conscripts underwent a hearing screening and filled out a noise exposure questionnaire at the beginning and end of their military service. Eighty-nine percent of the conscripts were exposed weekly to military noise of over 85 dBA during the service. Eighteen percent of the conscripts had already reached at the end of their military service a cumulative noise dose corresponding to noise exposure of 85 dB for 40 years. During military service, permanent hearing loss of > 20 dB in the frequency range of 0.5 to 8 kHz increased from 19 to 27% among the conscripts.

Obstructive sleep apnea in loudly snoring army conscripts.

One of the hallmarks of obstructive sleep apnea (OSA) is loud snoring. Army conscripts sleep in barracks, and loud snorers are easily detected. We made polygraphic recordings from these snorers during one night spent in the hospital, to find the ones suffering from OSA. Forty-nine conscripts (all male; mean age, 21 +/- 2 years; body mass index, 25 +/- 3 kg/m2) were studied; 32 (65%) complained about daytime sleepiness, and one had caused a shipwreck during an episode of fatigue. Oxygen levels decreased 4 to 9% >20 times per hour (4-9% oxygen desaturation index [ODI4] of >20 hours) for three subjects (6%). Eleven additional subjects (22%) had ODI4 values of >10 hours. Four (8%) of them did not complain about daytime sleepiness. The mean apnea index (AI) was 11 +/- 13 hours; 20 patients (41%) had AI values exceeding 10 hours. ODI4 and AI were significantly correlated (r = 0.67; p < 0.001). Body mass index did not correlate significantly with ODI4 or apnea index. Approximately one-fifth of loudly snoring conscripts suffer from OSA. Loud snorers should be examined before being selected for duties requiring maintenance of high alertness.

Acute sinusitis: Finnish clinical practice guidelines.

These clinical practice guidelines aim at providing assistance mainly to primary health care physicians for the diagnosis and management of acute sinusitis. Despite the huge impact of upper respiratory infections, criteria for diagnoses are often vague, and physicians are often uncertain of their diagnoses. This is not surprising, as the sole definition of acute sinusitis is somewhat confusing, not to mention the existing discrepancies between treatments, even among specialists. The Finnish Society of Otorhinolaryngology has set up a committee to evaluate existing data on acute sinusitis and to formulate these guidelines. The committee comprised Finnish experts in adult and paediatric otorhinolaryngology, clinical microbiology, radiology, paediatrics, and epidemiology. Recommendations given are based on the principles of evidence-based medicine, with the level of evidence presented.

Characteristics of acute acoustical trauma in the Finnish Defence Forces.

In spite of strict safety regulations concerning firearm shooting, several hundred conscripts still suffer acute acoustical trauma (AAT) in the Finnish Defence Forces (FDF) every year, resulting in symptoms such as tinnitus and/or hearing impairment. The causes leading to AAT, causative weapons and mode and level of hearing protection were analysed to find out why so many AATs still occur in the FDF. The material consisted of 119 patients of the total 163 AAT patients treated at the Central Military Hospital during the year 2000. In 87.5% of cases, the AATs occurred in unprotected ears. The most common causative weapon was the assault rifle. Most of the AATs occurred during combat training in the field. Immediately after the AAT. 46.7% of conscripts had hearing impairment and 94.2% tinnitus. Hearing loss, tinnitus or both were experienced by 45% of conscripts at the last follow-up. Careful planning of training exercises could probably prevent some but not all AATs.

Treatment of acute rhinosinusitis diagnosed by clinical criteria or ultrasound in primary care. A placebo-controlled randomised trial.

OBJECTIVES: To compare antibiotics and placebo in patients with clinically diagnosed acute maxillary sinusitis (AMS). To study whether sinus ultrasound examination would help to detect those patients who benefit from antibiotic therapy. DESIGN: A double-blind, randomised, placebo-controlled multicentre trial. SETTING: Nine primary care sites in Finland. SUBJECTS: 150 adult patients (mean age 39.7 years) with a clinical diagnosis of sinusitis. INTERVENTION: Antibiotics (amoxicillin 750 mg x 2, doxycycline 100 mg x 2 or penicillin V 1500 mg x 2) or placebo twice daily for 7 days; all patients were examined with sinus ultrasound after randomisation. MAIN OUTCOME MEASURE: Clinical success (patients' report of recovery) in telephone interview at 2 weeks. RESULTS: A total of 146 patients completed the 2-week follow-up. Patients receiving antibiotics achieved a slightly higher rate of clinical success than patients receiving placebo (80% vs 66%; p = 0.068). CONCLUSIONS: Antibiotics hasten symptom relief in AMS. Yet many patients recover in 2 weeks without antimicrobial treatment. Only half of patients with a clinical diagnosis of AMS have sinusitis in ultrasound examination.

Acute rhinosinusitis in primary care: a comparison of symptoms, signs, ultrasound, and radiography.

In primary care, the diagnosis of acute maxillary sinusitis (AMS) is based most often only on symptoms and clinical examination. This practice leads to many false positive diagnoses and unnecessary use of antibiotics. Sinus ultrasound has been suggested as a means to improve the accuracy of AMS diagnosis. We studied the symptoms, signs, and ultrasound findings in patients with acute rhinosinusitis. Primary care physicians received small group teaching on sinus ultrasound technique. Sinus radiography was performed in a subgroup of patients, and it acted as reference standard. A total of 150 adult patients were recruited to the study, 105 women (70%) and 45 men (30%). Thirteen patients of 32 (41%) in the radiography subgroup and 74 patients of 148 (50%) with ultrasound result had AMS. The sensitivity of ultrasound compared to radiography was 92% and specificity was 95% when results were calculated per patients as unit of analysis. With practice and teaching primary care physicians can perform sinus ultrasound as accurately as specialists. Symptoms and clinical examination were not reliable in AMS diagnosis. If the criterion for AMS diagnosis were fluid in maxillary sinuses in ultrasound instead of clinical impression, the number of antibiotic prescriptions would be reduced by half in primary care.

Noise attenuation and proper insertion of earplugs into ear canals.

OBJECTIVES: The study was done to determine whether the noise attenuation attained with the use of earplugs can be improved by teaching the proper insertion of earplugs to users. METHODS: Fifty-four randomly selected male subjects were divided into an untrained group (25 persons) and a trained group (29 persons). The trained group was given a lecture on earplug insertion and allowed to practise the insertion procedure, whereas the untrained group acted as controls. The untrained group received this training afterwards. The success of the training was measured by the MIRE (microphone in real ear) and REAT (real ear at threshold) methods, visual evaluation and an analysis of the properties of the subjects' ear canals. RESULTS: According to the MIRE method, the averaged A-weighted noise attenuation was 21 dB for the untrained group and 31 dB for the trained group. With the REAT method the attenuation at 1000 Hz was 24 dB for the untrained group and 30 dB for the trained group. The visual evaluation of the earplug fit was 1.9 for the untrained group and 2.6 for the trained group (scales 0-3). CONCLUSION: The results indicate that training in earplug insertion is important for good attenuation and for diminishing poor attenuation to a minimum.

Characteristics of tinnitus induced by acute acoustic trauma: a long-term follow-up.

We investigated the prevalence, characteristics and subjective perceived handicap caused by long-term tinnitus induced by acute acoustic trauma (AAT) in 418 former military conscripts. They had been treated between 1984 and 1989 because of AAT from exposure to impulse noise caused by firearm shooting. All 418 patients reported tinnitus after the AAT. At discharge from the military service, 122 (29%) still reported tinnitus. In 1999, of these 122 patients, 101 were reached and 66 still had tinnitus. The Tinnitus Handicap Questionnaire demonstrated various difficulties in life because of tinnitus, not attributable only to tinnitus loudness. Psychological factors also seem to play an important role. The effects of AAT and possible compensation have been evaluated so far mostly by audiometric findings, but in some cases tinnitus may be an even more serious threat to life satisfaction than mild hearing impairment.

On prediction of hearing recovery after acute acoustic trauma caused by impulse noise.

The present study investigates the prediction of how successfully hearing returns to normal after an acute acoustic trauma caused by a firearm shot, an explosion or other impulse noise. Study material consisted of 113 conscripts who had suffered an acute acoustic trauma during their military service. A logistic regression model was formed to predict hearing recovery. From several possible variables at least five were found to be important among our dataset, which is still rather limited. However, more data will be acquired later in order to elaborate the research more widely by using other methods also.