The characteristics of Audioscan and DPOAE measures in tinnitus patients with normal hearing thresholds.

OBJECTIVES: To investigate auditory dysfunction in patients with tinnitus and normal hearing thresholds using two sensitive audiological measures. DESIGN: The study was designed to investigate the characteristics of Audioscan and DPOAE tests in tinnitus patients with normal hearing thresholds. Audioscan and DPOAE notches were analysed and compared. All tests were performed in a sound-treated chamber or in a sound-treated room. STUDY SAMPLE: Forty-five tinnitus patients with normal hearing thresholds were examined following a written clinical protocol. RESULTS: The averaged hearing levels obtained from tinnitus participants were significantly worse at high frequencies than those derived from the normative data. There was a significantly higher prevalence of Audioscan and DPOAE notches, whose central frequencies matched tinnitus frequencies in the mid-frequency regions, but not in the low- and high-frequency regions. A significant correlation was found between the centre frequencies of the Audioscan notches and the DPOAE notches from 500 to 4000 Hz. CONCLUSION: Tinnitus in different frequency regions may be associated with different underlying mechanisms of tinnitus generation. Some negative results on the Audioscan and DPOAE notches matching tinnitus pitches may be due to a limited set of discrete frequencies used for the tinnitus pitch matching test.

French Society of ENT (SFORL) guidelines (short version): Audiometry in adults and children.

INTRODUCTION: French Society of ENT (SFORL) good practice guidelines for audiometric examination in adults and children. METHODS: A multidisciplinary working group performed a review of the scientific literature. Guidelines were drawn up, reviewed by an independent reading group, and finalized in a consensus meeting. RESULTS: Audiometry should be performed in an acoustically controlled environment (<30dBA); audiometer calibration should be regularly checked; and patient-specific masking rules should be systematically applied. It should be ensured that masking is not overmasking. Adult pure-tone audiometry data should be interpreted taking account of clinical data, speech audiometry and impedancemetry. In case of discrepancies between clinical and pure-tone and speech audiometry data, objective auditory tests should be perform. In children aged 2 years or younger, subjective audiometry should be associated to behavioral audiometry adapted to the child's age. In suspected hearing impairment, behavioral audiometry should be systematically supplemented by objective hearing tests to determine and confirm the level and type of hearing impairment.

Effects of an auditory startle stimulus on blood pressure and heart rate in humans.

OBJECTIVE: To describe the effects of an auditory startle stimulus on blood pressure (BP) and heart rate (HR) in humans. DESIGN AND METHODS: Twenty-five volunteers, including nine untreated hypertensive subjects, were studied in the supine position. Polygraphic recordings were obtained for finger BP, R-R interval using ECG, respiratory movements using a thoracoabdominal belt and for electrooculomyogram using adhesive electrodes. Haemodynamic estimations were derived by modelling flow from the noninvasive BP signal. A background noise of 55 dB was administered through headphones and two acoustic startle stimuli (110 dB, 1-20 kHz, 0.15 s) were generated at 5-min intervals during the tele-expiratory phase. The sham stimulation (0 dB, event marker) was compared with the effects of the noise stimulus (one-way ANOVA with repeated measures followed by a protected t test for multiple comparisons). RESULTS: A biphasic cardiovascular profile was observed in response to noise stimulation. Blood pressure and HR increases were combined in the early response (0-10 s) observed after the immediate motor contraction (blink). The average systolic BP rise was 18.7+/-2.7 mmHg (peak at 5.1 s) and the average HR increase was 10.8+/-1.1 bpm (peak at 3.4 s) for the first stimulus. These effects were highly significant compared with the sham response (P < 0.01). The second stimulus elicited BP and HR rises of a lesser amplitude (P < 0.01). The delayed response (10-30 s) corresponded with a moderate BP decrease. The haemodynamic indexes suggest that the early rise in blood pressure reflects a rise in total peripheral resistance. CONCLUSION: This is the first description of the BP response to an acute loud noise in humans. The early (within 10 s) BP and HR rises may depend upon the autonomic component of the startle reflex. One application of this test could be the discrimination of the different classes of antihypertensive drugs according to their sites of action.

Mortality of aluminium reduction plant workers in France.

The mortality between 1950 and 1976 of 6455 French aluminium plant workers was analysed in order to assess occupational risks (especially lung cancer) associated with electrolysis, particularly with the Söderberg process. Mortality from all causes (SMR = 0.85), was lower in this cohort than in the French male population ('healthy worker effect'), and cancer mortality (SMR = 1.09) was only slightly higher. There was an excess of mortality from accidents (mainly non-occupational) in electrolysis workers (SMR = 1.38) and from cirrhosis of the liver in maintenance workers (SMR = 1.63). Among electrolysis workers, only those who had worked less than 10 years had a relative excess mortality from lung cancer (SMR = 1.94), but this did not seem to be associated with a particular electrolysis process. However a substantial underlying risk of lung cancer in Söderberg workers could not be excluded, although such a risk appeared unlikely for prebake workers.

[Cardiovascular responses to a acoustic startle stimulus in man]. / Réponses cardiovasculaires à une alerte sonore chez l'homme.

OBJECTIVE: To describe the effects of an auditory startle stimulus on blood pressure (BP) and heart rate (HR) in man. Three sound levels were tested. DESIGN AND METHODS: Twelve normotensive volunteers were studied in supine position. Polygraphic recordings were obtained for finger BP, R-R interval using an electrocardiograph, respiratory movements using a thoracoabdominal belt and for electrooculomyogram using adhesive electrodes. A background noise of 55 dB was administered through headphones and the acoustic startle was generated using 3 synthetized white noises of 95, 110 or 120 dB administered at 5-min intervals during the tele-expiratory phase in a randomized order. Noise duration was fixed to 150 msec. The sham stimulation (0 dB, event marker) was compared to the 3 levels of noise (one way ANOVA with repeated measures followed by multiple comparisons). Confidence intervals (95%) were calculated for BP and HR using the 30 sec period preceding each stimulation to obtain individual significance of the responses for the 30 sec following each stimulation. RESULTS: A biphasic cardiovascular profile was observed following noise stimulation. The early response (0-10 sec) observed after the immediate motor contraction (blink) combined BP and HR increases. The average systolic BP rise was 15.9 +/- 2.6 mmHg (peak at 4.8 sec) and the average HR increase was 11.9 +/- 1.6 bpm (peak at 2.8 sec) for the 110 dB noise. These effects were highly significant compared to the sham response (P < 0.001). This 110 dB intensity determined 44% of significant systolic BP values and 25% significant HR values during this early period. Similar profiles were obtained with 95 and 120 dB with a lesser amplitude. The delayed response (10-30 sec) combined moderate BP and HR decreases. CONCLUSION: This is the first description of the BP response to an acute loud noise in man. The early (within 10 sec) BP and HR rises may depend upon the autonomic component of the startle reflex. The reproducibility of this cardiovascular profile obtained with a 110 dB white noise makes this test applicable to the clinical trials of antihypertensive drugs.

[Continuous electrocardiographic registration in occupational medicine]. / Enregistrement électrocardiographique continu en médecine du travail.

Continuous 24 hour electrocardiography (Holter method) was carried out during work time in 64 workers. They were divided into two groups: the first group comprised 34 subjects with either organic heart disease (coronary artery disease, valvular heart disease, operated coarctation, hypertrophic cardiomyopathy) or a documented arrhythmia without proven underlying cardiac disease; the second group comprised 30 subjects without known cardiac disease but complaining of symptoms suspected to be of cardiac origin or with isolated electrocardiographic abnormalities. At the end of the study we concluded that Holter monitoring is possible in subjects performing physical occupations even in difficult conditions. The trends of heart rate, especially mean heart rate calculated over 10 minute periods, confirmed the relationship between heart rate and the intensity of the physical activity. Atrial extrasystoles and episodes of supraventricular tachycardia were as common in the first as in the second group (20% and 18% respectively). This did not apply to ventricular extrasystoles: they were observed in both groups but were significantly more common in the first group (55% compared to 33%); ventricular extrasystoles, usually of a single configuration and isolated, were more common in the first group, especially amongst the coronary patients. Sinus node dysfunction was only observed in the second group (12.5%), in young subjects, and this occurred with only one exception at night. These findings support previous reports in the literature. However, the interpretation of these results is difficult because of the absence of well established normal values.

[Cardiac arrhythmia observed in 400 workers without obvious heart disease by Holter monitoring]. / Troubles du rythme cardiaque observés chez 400 salariés sans cardiopathie évidente par l'enregistrement Holter.

To obtain information on the cardiac rhythm characteristics of subjects without heart disease during their daily work, we examined the continuous 24-hour electrocardiographic recordings of 400 workers from 4 factories in Eastern France presenting with criteria of cardiac normality. Sex, age and socio-professional category were taken into account. Supraventricular extrasystoles were extremely common, being observed in 52 p. 100 of men and 39 p. 100 of women. In men, the frequency of these extrasystoles increased with age (p less than 0.001), and their number was less than 20 per 24 hours in 90 p. 100 of the cases. Ventricular extrasystoles were detected in 40 p. 100 of men and 32 p. 100 of women. They too were age-related, though not significantly. Their number was less than 10 per 24 hours in 68 p. 100 of the cases and 10 to 50 per 24 hours in 28 p. 100. These ventricular extrasystoles usually were monomorphous, regularly coupled (92 p. 100) and isolated. However, 2 attacks of tachycardia were discovered. Episodes of bradyarrhythmia (RR superior or equal to 1500 ms) were present in 25 p. 100 of men and 19 p. 100 of women. They occurred more frequently before the age of 35 than later (p less than 0.001) and the recordings confirmed that they were predominantly nocturnal. Recordings without "disorders of rhythm" were relatively rare (20 p. 100 of men, 28.5 p. 100 of women). Finally, there was no clear-cut correlation between the prevalence or characteristics of these various "rhythmic abnormalities" and the type of professional activity.

Audioscan: a high-definition audiometry technique based on constant-level frequency sweeps--a new method with new hearing indicators.

The resolution of data given by traditional fixed-frequency tone audiometry is limited to the number of frequencies tested. Numerical electronics now allow us to bypass the difficulties of controlled-level frequency sweeping. The Audioscan method gives a detailed audiometric curve and is designed to detect even the narrowest notches. The Audioscan method includes the possibility of defining hearing loss indicators containing more information and of increasing the diagnostic power of the audiometry. The applications both in the clinic and in screening are highly promising.

Epidemiological evaluation of hearing damage related to strongly amplified music (personal cassette players, discotheques, rock concerts)--high-definition audiometric survey on 1364 subjects.

Listening to loudly amplified music can be responsible for hearing damage of the same nature as that caused by industrial noise. This study of the repercussions on hearing is based on isolating different types of risks (PCPs (personal cassette players), discotheques and rock/variety concerts) using 'pure' exposed groups matched subject to subject for age and sex to control groups. Hearing is studied with high-definition audiometry and an 'auditory suffering' indicator. Although discotheque patrons present on average no audiometric damage (211 subjects), a statistically significant increase of average hearing thresholds is found in young people using a PCP > 7 h/week (54 subjects) compared to those using one 2-7 h/week (195 subjects) and compared to their matched controls. The same is true for subjects who go to rock concerts at least twice a month (87 subjects) compared to their matched controls. Signs of auditory suffering are found in two subjects out of three in this last exposure group, as opposed to 12% of the controls. Measures to conserve young people's hearing must include a reduction of sound levels, the education of music and entertainment professionals, and making PCP users better informed.

Hearing loss due to partly impulsive industrial noise exposure at levels between 87 and 90 dB(A).

A cross-sectional epidemiological survey was carried out in a car-body workshop involving 234 workers divided into three groups according to age and noise exposure duration. Their hearing levels, determined by using a standardized audiometric testing procedure, were compared to those of a reference population not exposed to noise, to those of a population exposed to quasisteady noises at 95 dB(A), and also to ISO 1999-1987. Results reveal significant hearing loss after 9 years of exposure, greater than that from quasisteady noise exposure with the same equivalent continuous A-weighted sound-pressure level.

The Audioscan: a high frequency resolution audiometric technique and its clinical applications.

The Audioscan is a form of high definition audiometry based on iso-hearing level frequency sweeps, which was developed by Meyer-Bisch in 1990. Compared with traditional tone audiometry, it sweeps across the preset frequency range at a predetermined sweep rate and provides a continuous audiometric curve. Because the device has a maximum frequency range of 125-16 000 Hz with 64 frequencies per octave, the Audioscan method can, theoretically, give 64 times as many values as fixed-frequency audiometry, which may give greater accuracy and sensitivity. An advantage of this is its capacity to detect mild audiometric deficits such as narrow notches situated between the frequencies normally tested. These may represent very limited auditory lesions, at a stage when they cannot be detected by routine audiological methods. Thus, the Audioscan method can give not only a detailed audiometric curve, but also provide important indicators of mild auditory dysfunction. The Audioscan device (e.g. Essilor model) is commercially available for clinical purpose. It is a software-based system, which can also be used for pure tone audiometry and Békésy audiometry. This paper reviews the general aspects of the Audioscan technique and current applications for detecting auditory dysfunction. This would be valuable to provide some guidelines on the Audioscan assessment, and contribute to a clarification of the clinical application of Audioscan and facilitate further research.

A study of the prevalence of acute respiratory disorders among workers in the textile industry.

An epidemiological study of 774 workers in seven eastern France cotton textile factories was conducted to determine the prevalence of acute respiratory disorders. From nine non-textile companies, 464 workers, stratified as to sex, age and tobacco consumption participated in the study as a control population. A questionnaire designed to elicit the respiratory symptoms (in particular the Monday tightness characterizing byssinosis) was administered to the 1238 workers. Peak-expiratory-flow (PEF) measurement was made for each subject, exposed and non-exposed, before the start of the shift on the day of the worker's return to work and repeated at the end of the shift. The PEF's variations during the workshift were studied. Present Monday tightness was mentioned by 48 cotton exposed workers (6.2%) and by 9 non-exposed (1.9%) (P less than 0.001). A 10% decrease in PEF during the shift was present in 63 cotton exposed workers (8.1%) and in 10 non-exposed (2.1%) (P less than 0.001). For the exposed population, Monday tightness was analysed using multiple logistic regression, showing an absence of a link with smoking, an increased occurrence after 20 years of exposure (OR = 7.3) and a link with current job (more frequent among those with the dustiest jobs) (OR = 4.9). The multiple logistic analysis of a 10% decrease in PEF showed effects of smoking habits (OR = 1.86). It also showed a link with "highly polluted job" history (OR = 2.7), but especially with present job (OR = 3.4). The absence of a constant link between Monday tightness and drop of the PEF was found.

[Study of the pulmonary function of arc welders. Results of a study in an industrial vehicle production plant]. / Etude de la fonction pulmonaire de soudeurs à l'arc. Résultats d'une enquête dans une entreprise de construction de véhicules industriels.

Pulmonary examinations (i.e. clinical, functional and radiological) were conducted on 76 arc welders from an industrial vehicle production plant and on 74 'controls' from the same plant. Arc welders were exposed for an average of 11 years to welding gases and fumes; controls were not welders and were not exposed to any identifiable professional risk of pulmonary disease. There is no significant difference between these two groups concerning clinical, functional and radiological findings; but the prevalence of pulmonary abnormalities (whatever their type or their intensity) is high in the two groups (60%). This survey does not show any particular risk of pulmonary disease among the arc welders working in this plant. However, complementary studies in other industrial areas are required to investigate possible risks due to other arc-welding processes and other working conditions.

Effects of chronic exposure to diisocyanates.

The pulmonary effects of chronic exposure to isocyanates (mainly MDI) at low levels (less than 0.02 ppm) were studied in a five year longitudinal survey of workers from two factories producing polyurethane foam. A respiratory questionnaire, flow volume curves and a single breath CO diffusion test were done at the beginning of the survey and repeated five years later; 318 workers (214 men, 104 women) of whom 83 (group I) were unexposed, 117 indirectly exposed (group II) and 118 directly exposed to isocyanates (group III) were examined. Five years later, half of the initial cohort only was still active and re-examined. The longitudinal analysis distinguished unexposed workers at both examinations (group A), indirectly at both examinations (group. B), directly exposed at both examinations (group. C) and workers exposed directly at first examination and retired from risk at the second (group. D). The decline of VC and FEV1 was not significantly different between exposed and unexposed. On the contrary, DLCO declined significantly in group C compared to the others. The results indicate that even at 'safe levels', chronic exposure to isocyanates involved a respiratory risk.

Reduction of pulmonary function indices: comparison of two hierarchical methods.

From tests for evaluating pulmonary function many indices may be calculated. In order to reduce their redundancy, two hierarchical methods for selecting the most significant indices are applied to data collected on a group of 228 firemen. The first method consists in a stepwise linear discriminant analysis which selects the indices according to their discriminant value for distinguishing between asymptomatic and symptomatic subjects. The second one is derived from a stepwise multiple correlation procedure, which selects the indices on the basis of their linear relationships. These two methods lead to different results and the choice between them should be made according to the aims intended for data reduction.

[Pulmonary function indices: variability, predicted values and discriminating power (author's transl)]. / Indices fonctionnels respiratoires: variabilité, valeurs de référence et pouvoir discriminant.

Flow/volume curves, single-breath N2 washout curves, single-breath and steady-state carbon monoxide diffusion tests were performed on 229 firemen (aged 20 to 55 years) and repeated one week later on 183 of them. According to a questionnaire, 58 were asymptomatic non-smokers, 130 were asymptomatic smokers and 34 were smokers with symptoms of cough with or without sputum. Intra-individual variability of indices determined from tests performed at a week interval is not always aleatory and it is different in the three groups. It is the same for inter-individual variability which is lowest in asymptomatic smokers and highest in symptomatic smokers. Age and height were the most important factors in inter-individual variability for spirometric indices but do not affect the variability of the slope of N2 curve (delta N2) or fractional uptakes of CO. The ratio of residual variance (adjusted for age and morphometric parameters) on intra-individual variance indicated the choice of "sensitive" functional indices. This choice may be reached in a different way by comparison of means of groups distinguished according to symptoms or smoking habits. Reference equations for indices derived from each test are proposed. The problem of the choice of "sensitive" indices and the problem of reference groups and reference values are discussed.

Risk of lung cancer among iron ore miners: a proportional mortality study of 1,075 deceased miners in Lorraine, France.

A proportional mortality study of 1,075 iron ore miners in Lorraine, France, who died between 1960 and 1976 showed a significant excess of lung cancer mortality (proportionate mortality ratio = 2.25). Moreover, proportionate lung cancer mortality increased with the duration of work underground (proportionate mortality ratio = 4.24 for subjects who worked underground for more than 30 years) and was higher among pneumoconiotic (siderotic) miners (proportionate mortality ratio = 3.85) than among nonpneumoconiotic miners. These results were confirmed by a case-control study nested in the mortality study. Smoking habits could not be estimated retrospectively with sufficient accuracy to be taken into account. Although the proportion of smokers among contemporary iron ore miners is larger than in the French male population, occupational factors may also play a role; radiation exposure can be ruled out because there is no detectable radioactivity in the Lorraine mines, but dust exposure may be considered as an etiologic factor owing to the relationship between siderosis and lung cancer.

Lung function and clinical findings in a cross-sectional study of arc welders. An epidemiological study.

An epidemiological, cross-sectional study was conducted in order to assess non-neoplasic effects on the lung due to chronic exposure to arc welding fumes and gases. The study involved 346 arc welders and 214 control workers from a factory producing industrial vehicles. These workers (welders and controls) had never been exposed to asbestos. Respiratory impairments were evaluated by using a standardized questionnaire, a clinical examination, chest radiophotography and several lung function tests (spirometry, bronchial challenge test to acetylcholine, CO transfer tests according to the breath-holding and the steady-state methods, N2 washout test). The only significant differences between the welders overall compared to the controls were a slightly higher bronchial hyper-reactivity to acetylcholine and a lower lung diffusing capacity for CO in the welders. However, non-specific, radiologic abnormalities (reticulation, micronodulation) and obstructive signs were more frequent in the most exposed welders (welding inside tanks) than in welders working in well ventilated workplaces. The nature of the metal welded (mild-steel, stainless steel, aluminium) did not seem to have an influence on respiratory impairments. In the mild-steel welders, respiratory symptoms (dyspnoea, recurrent bronchitis) and obstructive signs were more frequent in the welders using a manual process than in the welders involved with the semi-automatic process (MIG). For all the workers (welders and controls), smoking had a markedly adverse effect on respiratory symptoms and lung function. Moreover, smoking seemed to interact with welding since CO lung transfer was more impaired in smoking welders than in smoking controls.

Arc welders' respiratory health evolution over five years.

The respiratory health of 138 arc welders and 106 control subjects in the same company was studied in 1981 and in 1986. Most of the subjects welded mild steel using the Metal Inert Gas (MIG) process. The controls were workers in the same company, not exposed to any known pulmonary risk. The welders and controls in the analysis had not changed their professional activity nor their smoking habits during these five years. The examinations consisted of a questionnaire on respiratory symptoms, a thoracic auscultation, a chest X-ray and lung function tests: flow-volume curve and steady state CO transfer test. The examinations in 1986 confirmed the risk of non specific radiological impairment (pulmonary reticulo-micronodulation) and of obstruction in the small bronchi, which had already been observed in 1981 in the arc welders in this company. These impairments did not seem to have evolved more than in the controls, but do however justify regular surveillance of the respiratory health of arc welders.

Respiratory hazards in hard metal workers: a cross sectional study.

A cross sectional study was conducted on 513 employees at three hard metal plants: 425 exposed workers (351 men, 74 women) and 88 controls (69 men, 19 women). Cough and sputum were more frequent in workers engaged in "soft powder" and presintering workshops compared with controls (12.5% and 16.5% v 3.5%). Spirometric abnormalities were more frequent among women in sintering and finishing workshops compared with control women (56.8% v 23.8%) and abnormalities of carbon monoxide test were more frequent in exposed groups than in controls; this difference was more pronounced in women (31.4% v 5.6%) than in men (18.5% v 13%). No significant correlation was observed between duration of exposure and age adjusted lung function tests. Slight abnormalities of chest radiographs (0/1, 1/1 according to ILO classification) were more frequent in exposed men than controls (12.8% v 1.9%) and mostly in soft powder workers. In subjects with abnormal chest radiographs FVC, FEV1 and carbon monoxide indices (fractional uptake of CO or CO transfer index or both) were lower compared with those with normal chest radiographs. Although relatively mild, the clinical, radiological, and functional abnormalities uncovered call for a regular supervision of workers exposed to hard metal dust.