Diseases of the ear and hearing damage - 547 entries found
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- Diseases of the ear and hearing damage
The future evolution of the occupational disease "noise-induced hearing loss and deafness" - Forecast and consequences
Die zukünftige Entwicklung der Berufskrankheit "Lärmschwerhörigkeit und Lärmtaubheit" (BK 26) - Prognose und Folgerungen [in German]
From data concerning notified and compensated cases of noise-induced disease from 1950 to 1972 in the Federal Republic of Germany and using the pattern of the evolution of silicosis from 1930 to 1970, a statistical prognosis for noise-induced diseases up to 1985 is presented. It is concluded that these will reach about 4,000 cases in 1982, that is, as high as the overall total compensated occupational diseases in 1971. Consequences and measures concerning the insured workers, the size of the noise problem and noise exposure are listed.
Die Berufsgenossenschaft, Mar. 1974, No.3, p.127-136. Illus.
Hearing damage due to noise
Hørselsskader fremkalt av larm [in Norwegian]
Introduction to the physics of noise, units of measurement of noise and physiology of hearing, followed by a study of the effects of noise on hearing: thresholds of discomfort and pain, tinnitus, loss of hearing assessed by pure-tone and speech audiometry. The author recommends the following methods of hearing protection: work organisation reducing the time of exposure to noise; wearing of earmuffs; use of earplugs (but not dry cottonwool plugs); periodical audiometric examinations.
Direktoratet for arbeidstilsynet, Postboks 8103, Oslo-Dep., Norway, 1974. 15p. Illus. 7 ref. Gratis.
Les surdités professionnelles [in German]
Les surdités professionnelles. [in French]
This publication, which is principally intended for medical practitioners who have not had special training in acoustics and otology, deals with the following: physical data concerning noise; sources of hazard (noise causing hearing damage); pathogenesis and clinical picture; treatment; prevention; compensation; statistics.
Maladies professionnelles, Leaflet No.12. Swiss National Accident Insurance Institute (Schweizerische Unfallversicherungsanstalt), Luzern, Switzerland, Feb. 1974, 12p. Illus. 11 ref.
Edmonds C., Freeman P., Thomas R., Tonkin J., Blackwood F.A.
Otological aspects of diving.
This book is addressed to medical practitioners generally who are associated with divers, and not specifically to otologists. Contents: anatomy and physiology of the ear; the Eustachian tube and nasal function; diving physics; infections of the ear; decompression sickness; aural barotrauma; hearing loss in divers; vertigo and disorientation in diving; exostoses and external, middle and inner ear injuries; otological standards for diving.
Australasian Medical Publishing Company Ltd., 71-79 Arundel Street, Glebe, N.S.W. 2037, Australia, 1973. 101p. Illus. 49 ref.
Some clinical and physiological studies of workers subjected to stable noise.
Translation of: Nekotorye kliniko-fiziologičeskie issledovanija u rabočih, podvergaju¿čihsja dejstviju stabil'nogo ¿uma. Gigiena truda i professional'nye zabolevanija, Moskva, USSR, Dec. 1966, Vol.10, No.12, p.23-27. 21 ref. Examination of a group of 172 male and female operators of turret lathes (noise level 82-87dB) and automatic turret lathes (noise level 92-99dB), exposed to continuous noise in the medium and higher frequencies (reaching a maximum in the 250-4,000Hz range), brought to light the prevalence of functional nervous system disorders in the shape of an asthenic-vegetative syndrome affecting 29.4% of the turret lathe operators and 43% of the automatic turret lathe operators. Functional haemodynamic changes were also noted. The extent and frequency of the changes were correlated to the noise level and duration of exposure. A number of the workers proved to be suffering from hearing loss in the high frequency range, being greatest at about 6,000Hz; the extent of the loss (15-30dB) was also proportional to noise level and duration of exposure.
Army Foreign Science and Technology Center, Charlottesville, Virginia. AD-772 449/5WJ, National Technical Information Service, Springfield, Virginia 22151, USA, 7 Dec. 1973. 7p. 21 ref. Price: Photocopy US-$4.00/Microfiche US-$1.45.
Committee on Hearing and Equilibrium, American Academy of Ophthalmology and Otolaryngology, Baylor College of Medicine, 1200 Moursund Avenue, Houston, Texas 77025.
Guide for conservation of hearing in noise.
The purpose of this guide is to assist physicians and the industrial community in their efforts to protect hearing. The information presented describes how to determine whether a noise exposure calls for hearing conservation practices; and, if it does, how to organise, conduct, and monitor a practical hearing conservation programme. The statements made are based on both clinical and industrial experience, and on knowledge gained from research. The booklet includes summaries of basic information about hearing loss and noise exposure, a broad outline of a hearing conservation programme, and a discussion of procedures recommended for executing the programme. An appendix refers to Hearing Loss Statutes in the United States and Canada, with a table indicating details of compensation awards for numerous types of damage in each of the 52 States and territories of the U.S. and in Canada.
Transactions of the American Academy of Ophthalmology and Otolaryngology, Supplement to Rochester, Minnesota, USA, revised edition, 1973. 46p. 38 ref. Price: US-$1.00.
Noise and man.
This handbook is an introduction to the subject of noise and its effect on man and is intended for audiologists, engineers, industrial and general physicians, otologists, physicians and health physicists, safety officers, psychologists, public health officers and administrators, and deals with: the physical properties of sound; types of sound; measurement of sound; the mechanism of hearing; normal hearing and its measurement; deafness; disturbance, annoyance and effect on health; measures to reduce disturbance; temporary effects of noise on hearing; permanent effects of noise on hearing; preservation of hearing; aircraft noise; impulse noise, intense noise, ultrasound, infrasound, sonic boom and vibration; and present and future industrial and community noise. Appendices include: a glossary of acoustical terms; a guide to units of measurement; ANSI, BSI and ISO recommendations on acoustics; decibel conversion tables; calculations of sound pressures and intensities; and information on audiometry, etc.
John Murray, 50 Albemarle Street, London, United Kingdom, 2nd enlarged edition, 1973. 459p. Illus. 423 ref. Price: £5.00.
Use of ultrasound for the diagnosis of hearing damage
Zur Diagnostik von Lärmhörschaden mit Ultraschall [in German]
An account of research on methods of using the perceptive capacity of ultrasound in audiometric tests for the early diagnosis of impaired hearing. Frequencies of 20, 40 and 60kHz were used. According to the results obtained, the threshold of sensitivity to ultrasound is appreciably higher in persons with diminished hearing acuity. This result was confirmed statistically at 20kHz frequency. It is therefore possible to carry out ultrasound examinations during work in a noisy environment and to use this technique for routine checks for early diagnosis. A possible mechanism whereby ultrasounds are perceived is discussed.
Das deutsche Gesundheitswesen, 1973, Vol.28, No.20, p.950-956. Illus. 5 ref.
Influence of industrial noise of different intensities on the acoustic analyser and the central nervous system of young workers
Vlijanie proizvodstvennogo šuma različnyh parametrov na sluhovoj analizator i central'nuju nervnuju sistemu rabočih-podrostkov [in Russian]
Results of pure-tone audiometry and reflex measurement tests with optical and acoustic stimuli carried out on 56 young workers aged 16 to 19 exposed to noise levels of 85, 80 and 65dB in metalworking shops. The results are given in tabular form. The author found a direct relationship between functional disorders and noise levels. A noise level of 80dB, which is threshold limit value for adults, has too great an effect on young persons and causes serious functional disturbances.
Gigiena truda i professional'nye zabolevanija, July 1973, No.7, p.5-9. 20 ref.
Acute pancochlear hearing impairments, in particular those caused by noise
Akute pancochleäre Höreinbussen mit besonderer Berücksichtigung ihrer Auslösung durch Lärm [in German]
This thesis contains an analysis of 30 cases of pancochlear hearing impairment reported in 5 years to the Swiss National Accident Insurance Institute; 23 cases were of occupational origin. Data include age, medical history, type of occupational exposure to noise and cause of impairment, subjective symptoms, results of ear, nose and throat examinations and diagnosis. Pathogenesis is discussed in the light of existing literature. It seems that a distinction cannot be made between acute pancochlear hearing impairment caused by noise and an impairment not caused by noise, and that only the intensity of the noise is decisive. Considerations on treatment, prevention and medico-legal aspects.
Schweizerische Unfallversicherungsanstalt, Postfach, 6002 Luzern, Switzerland, 1973. 60p. Illus. 33 ref.
Rossi M., Sfogliano C.
Observations on the prevention of hypacusia due to prolonged auditory trauma
Rilievi sulla prevenzione della ipoacusia da trauma acustico continuato [in Italian]
On the basis of the audiological data of workers in a steelworks, the authors recommend to pay particular attention in preventive medical examinations to the pharmacological anamnesis of the persons concerned. Among the workers examined and particularly among those with the most marked auditory impairment, gastro-intestinal disorders treated by different drugs not considered ototoxic were found. Systematic research in this direction is suggested to collect sufficient observations to identify which drugs make the ear most vulnerable to noise.
Folia medica, Jan.-Feb. 1973, Vol.56, No.1-2, p.24-33. Illus.
Maksimova L.I., Pomeranceva N.V.
The effect of impulse noise on workers' hearing
Dejstvie impul'snogo šuma na sluh rabočih [in Russian]
After determining the physical characteristics of continuous noise and of several varieties of impulse noise (noise caused by stamping and punching presses, polishing machines, hand and pneumatic hammers), the authors examined the hearing of 220 workers exposed partly to impulse noise and partly to continuous noise. They found that impulse noise with an impulse duration of 20 to 100ms and a frequency of 1 to 15Hz did not cause more pronounced or more frequent hearing impairment when compared with continuous nose, except in cases where the acoustic pressure level exceeded that of continuous noise by 15 to 30dB.
Gigiena i sanitarija, Sep. 1973, No.9, p.33-36. 6 ref.
Chaney R.B., McClain S.C., Harrison R.
Relation of noise measurements to temporary threshold shift in snowmobile users.
Noise measurements were carried out at the ear level of 18 snowmobile operators; audiometric examinations indicate that temporary threshold shifts of varying degrees occurred in 87% of the operators after operational periods as short as 30 min. Sound levels at full throttle were as high as 114 dBA (90 dBA with the engine running idle). Results of sound level tests on 23 models of snowmobile are tabulated.
Journal of the Acoustical Society of America, 1973, Vol.54, No.5, p.1219-1223. Illus. 8 ref.
Department of Health and Social Security, London.
National Insurance (Industrial Injuries) Act 1965 - Occupational deafness.
Report by the Industrial Injuries Advisory Council under the above Act, on the question whether there are degrees of hearing loss due to noise which satisfy the conditions for prescription under the Act, and for which compensation may be claimed. The Council was required to find, inter alia, if noise-induced hearing loss was a "disease" within the meaning of the Act, and could the extent of occupational noise injury be distinguished (problems of diagnosis and assessment)? The Council concludes that occupational deafness may fullfil the conditions laid down by the Act, provided that deafness due to occupational noise is substantial, appropriate technical and medical services are available for diagnosis and assessment, and there is a closely drawn occupational cover. It is recommended that occupational deafness should be prescribed under the Act and that a benefit scheme should be started. The prerequisites for the scheme are indicated.
H.M. Stationery Office, P.O. Box 569, London S.E.1, United Kingdom, Oct. 1973. 54p. Price: £0.365.
Pierson W.R., Mahé J.E.
Noise and the highway patrolman.
A study to determine the effect of routine patrol activity on hearing acuity. 15 patrol car officers and 4 motorcycle officers were investigated. Audiograms were recorded just before a patrol and immediately upon return from a patrol of approximately 5 h. The study revealed that the subjects began their duty with a hearing loss characteristic of that due to acoustic trauma, indicating that the permanent threshold had been degraded by previous noise exposures. It was also evident from the data that the patrol caused temporary hearing loss. A rigorous hearing conservation programme appears to be advisable for those engaged in highway patrol duties.
Journal of Occupational Medicine, Nov. 1973, Vol.15, No.11, p.892-893. Illus. 5 ref.
Coles R.R.A., Martin A.M.
Medico-legal aspects of occupational hearing loss.
A review of the medico-legal situation concerning occupational hearing loss in the United Kingdom, covering the events leading up to the present situation and probable future trends. Individual sections are devoted to: the sections of the United Kingdom Factories Act, 1961 related to noise hazards; the terms of the United Kingdom National Insurance (Industrial Injuries) Act, 1965 which provide for financial compensation to be paid for disability arising from employment accidents but which does not cover noise-induced hearing loss of slow onset; and common law provisions in the United Kingdom under which action against an employer for damages in respect of occupational hearing loss was first brought in 1968.
Journal of Sound and Vibration, 8 June 1973, Vol.28, No.3, p.369-373. 9 ref.
Kryter K.D., Cohen A., Davis H., Lempert B.L., Ward W.D.
Impairment to hearing from exposure to noise.
An article by Kryter (p.1211-1234) reviews the current situation and puts forward the opinion that commonly used methods for evaluating hearing impairment and the relationship of such impairment to noise exposure may significantly underestimate the severity of the impairment and overestimate tolerable noise-exposuure limits. Criteria for acceptable degrees of hearing impairment for speech and a criterion of an acceptable percentage of people to suffer noise-induced hearing impairment are suggested. A unit of equivalent noise measurement called "speech impairment risk" is proposed for use in setting tolerable limits of exposure to non-impulsive and impulsive noise with respect to the above criteria or other suitable criteria. The article is followed by papers giving critical comments by Cohen, Davis, Lempert and Ward, and finally a reply to these critiques by Kryter himself.
Journal of the Acoustical Society of America, May 1973, Vol.53, No.5, p.1211-1252. Illus. 75 ref.
Noise-induced hearing loss: The energy principle for recurrent impact noise and noise exposure close to the recommended limits.
Discusses the approach needed to confirm D.W. Robinson's energy principle as applying to noise exposure. Data are presented supporting the energy principle for exposure to recurrent impact noise and exposure corresponding closely to 2 recommended exposure limits: the British Occupational Hygiene Society's 1971 hygiene standard for wide-band noise (CIS 198-1972, Bik Qez (627)) specifying a maximum noise immission level for a working lifetime, and the U.K. Department of Employment's 1972 code of practice for reducing the exposure of employed persons to noise (CIS 2682-1972, Bik Qay Sgw (627)). Data from a previously published study of drop forgers (CIS 1921-1971, Bik Qay) are used to exemplify the method used. A discussion between the author and various experts is briefly reported.
Annals of Occupational Hygiene, Aug. 1973, Vol.16, No.2, p.183-194. Illus. 14 ref.
Kubík Š., Vladár M.
Experimental study of temporary shift of hearing threshold due to continuous noise
Experimentálna štúdia o dočasnom posune sluchového prahu z kontinuálneho zvuku [in Slovak]
42 subjects (mostly students between 16 and 26 years of age) were exposed to noise for several periods of 4 h each. Sound pressure was made to vary between 75 and 100 dB, and frequency between 250 and 10,000 Hz (by stages of 500, 1,000, 2,000 and 4,000 Hz). The hearing threshold was determined before exposure and after 2 and 4 h of exposure. Sound pressure of 75 dB or less does not produce any abnormal threshold shift, whereas significant shifts are observed at 90 dB and over. The most significant variations were observed in the frequency band 4,000-6,000 Hz (according to sound pressure) and the smallest variations between 250 and 500 Hz.
Pracovní lékařství, Jan. 1973, Vol.25, No.1, p.5-10. Illus. 8 ref.
Quevauviller A., Levrier-Pottier J.
Physiopathological effects of noise
Effets physio-pathologiques du bruit. [in French]
Specific action of noise on the auditory function (masking effect, auditory fatigue, acoustic trauma), effect on the central nervous system, effect on the major functions: respiratory, renal, digestive and endocrine systems. Cellular and physiological changes, biological repercussions.
Revue de la sécurité, June 1973, Vol.9, No.92, p.32-39. 77 ref.
Noise and its harmful effects
Buka i njena štetna dejstva [in Serbocroatian]
A review of present knowledge on noise and its effects: physics of noise and sound; physiology of hearing; noise measurement and analysis; hearing damage risk criteria; noise-induced hearing loss; audiometry; criteria for the assessment of work capacity in the event of noise-induced hearing loss; extra-auditory effects of noise (on the central nervous system, and on heart rate and cardiac activity); protection against the harmful effects of noise (principles of collective and personal protection); biological effects of ultrasound and infrasound.
Institut jugoslovenske i inostrane dokumentacije zaštite na radu, Ulica Stanka Paunovića 17/1, Niš, Yugoslavia, 1972. 182p. Illus. 94 ref. Price: Din.70.00.
Portmann M., Portmann C.
Clinical audiometry manual with audiometric atlas
Précis d'audiométrie clinique avec atlas audiométrique. [in French]
Handbook for use of medical practitioners, technicians conducting hearing tests and speech therapists. Chapters are devoted to: units and graphs, hearing thresholds; equipment and conditions for audiometric examinations (acoustic booths, etc.); ordinary pure-tone audiometry; automatic audiometry; special pure-tone above-threshold audiometric tests; conversational audiometry; objective audiometry; audiometric study of deafness according to site of lesions; audiometric aspect of deafness according to aetiology, atlas of clinical observations; role of audiometry in forensic medicine and occupational health; hearing aids.
Masson, 120 Boulevard Saint-Germain, 75006 Paris, France, 4th edition, 1972. 325p. Illus. Price: FF.96.00.
Hunter-Duvar I.M., Elliott D.N.
Effects of intense auditory stimulation: Hearing losses and inner ear changes in the squirrel monkey.
In order to study theories of the relationship between hearing loss and hair cell damage in the organ of Corti, squirrel monkeys were exposed to pure-tone noise at intensities (120 dB) and durations (25 min - 12 h) sufficient to produce repeated temporary threshold shifts (TTS) of 15-25 dB in half the group and permanent threshold shifts (PTS) of 10-20 dB in the remainder. The animals were sacrificed, and the effects of noise exposure on hair cells was determined by surface preparation techniques and phase microscopy. The organ of Corti was examined over its whole length and the number of missing and visibly damaged hair cells along a specific length of the inner and outer rows was determined. There was no clear evidence of cell damage due to exposure. It is concluded that exposure to pure-tone noise sufficient to produce PTS of 10-20 dB does not necessarily produce anatomical injuries in the organ of Corti that are detectable by phase microscopy.
Journal of the Acoustical Society of America, Oct. 1972, Vol.52, No.4 (Part 2), p.1181-1192. Illus. 33 ref.
Okada A, et al.
Temporary hearing loss induced by noise and vibration
5 audiometrically normal subjects were exposed to (1) steady-state noise (101dB), (2) vibration (2 to 20Hz at 100 to 1000cm/s2), and (3) noise plus vibration. The main experimental conclusions were that exposure to vibration of 5Hz and 500cm/s2 (5Hz being the resonance frequency of the human body) produces a significant temporary threshold shift, and that hearing loss from noise may under certain circumstances be increased by simultaneous exposure to vibration.
Journal of the Acoustical Society of America, Apr. 1972, Vol.51, No.4 (Part 2), p.1240-1248. Illus. 16 ref.
Cohen A., Anticaglia J.R., Carpenter P.L.
Temporary threshold shift in hearing from exposure to different noise spectra at equal dBA level
The purpose of this study was to determine whether sound-level measurements in dBA could provide a satisfactory indication of hearing-loss risks from exposures to noises differing greatly in spectral shape. The experimental method is described and the results presented and discussed. Somewhat greater hearing losses were found for noises with falling spectra than with rising spectra at comparable dBA levels, but the differences were rather small.
Journal of the Acoustical Society of America, Feb. 1972, Vol.51, No.2 (Part 2), p.503-507. Illus. 14 ref.
Hyperbaric chamber noise during a dive to 100ft.
Diving in hyperbaric chambers can produce both temporary and permanent threshold shifts. The purpose of the present study was to determine the noise levels in such a chamber during compression to a simulated depth of 30m of sea water. The experimental procedure is described, and the results discussed. Peak noise levels during descent and ascent were in the 2400-4800 Hz octave band (112-108dBA and 120-115dBA, respectively, depending upon the microphone position).
Journal of the Acoustical Society of America, Apr. 1972, Vol.51, No.4 (Part 2), p.1362-1365. Illus. 7 ref.
Hearing and personality: A review
The personality of individuals interacts with their auditory system in a variety of ways. Subjects with different personalities may differ in their psychological responses to sounds, in their perception of sounds and in the way in which noise influences their performance of various tasks. Severe deafness appears to influence the personality of patients, and fairly characteristic changes are found in specific auditory disorders. The annoyance caused by a variety of noises is influenced by the person's personality and, in the past, a noise annoyance scale hs been used as a measure of neuroticism.
Journal of Sound and Vibration, 8 Feb. 1972, Vol.20, No.3, p.287-298. 92 ref.
Gasaway D.C., Sutherland H.C.
Comparison of A-weighted auditory risk criteria with octave-band estimates
This report compares various criteria based on A-weighted sound levels with the critical limits based on octave-band data as proposed by CHABA. The spectral noise distribution influences the degree of auditory risk associated with single dBA values, and current dBA hearing damage criteria yield widely different estimates of auditory risk and must therefore be used and interpreted with extreme caution. The differences between various criteria emphasise the need to perform auditory monitoring of personnel exposed to potentially hazardous noise, since audiometry provides the only method by which hearing loss due to noise can be correctly identified.
Report SAM-TR-71-19, School of Aerospace Medicine, Brooks Air Force Base, Texas 78235, USA, July 1971. 14p. Illus. 30 ref.
Harford E.R., Matkin N.D.
Interpretation of audiograms and the implications of industrial hearing loss on communication
A brief description of the auditory mechanism and sections devoted to: the audiogram; air and bone conduction tests; degree of hearing loss; common audiometric configurations (illustrated by numerous diagrams); implication of industrial hearing loss on communication; hearing versus understanding; and increased dependence upon vision.
National Safety News, Apr. 1972, Vol.105, NO.4, p.77-78. Illus.
Čuprová L., Stojanov I.
The hazards of intermittent noise in the use of bolt guns in the building industry
Riziko impulsního hluku vstřelovačů ve stavebnictví [in Czech]
Results of comparative studies on the firing technique (direct or hammer-actuated), the make of gun, the calibre, the power of the explosive charge and the size of the premises, on the noise level. The maximum instantaneous noise level, the duration of the noise impulse and the duration of the initial reflex were recorded by means of an oscillograph. Hearing lesions detected by audiometry in bolt-gun users were correlated with duration of exposure. It was found that hammer-actuated bolt guns are preferable from the occupational health point of view. The 9-mm cartridges were extremely dangerous from the noise point of view and their use should be restricted. Under present conditions, it is necessary to make use of personal protective equipment to prevent noise-induced hearing damage. Efforts should therefore be made to improve the design of bolt guns and achieve greater noise reduction.
Pracovní lékařství, 1972, Vol.24, No.5, p.162-167. Illus. 12 ref.
The meaning of modern audiological tests in relation to noise-induced deafness: A review
A review of the problems involved in the detection of deafness in industrial workers and, in particular, the decision as to whether the hearing loss found is attributable to noise damage. The procedures likely to be required should noise-induced deafness become a prescribed occupational disease in the United Kingdom, are considered. After a short description of the initial screening procedure, special attention is devoted to persons who have failed to pass the requisite minimum hearing standard, and it is described how modern hearing tests help to differentiate between various types of hearing loss (conductive and sensorineural). The problem of malingering (non-organic hearing loss) is also considered, and it is concluded that the well-equipped otologist should be able to diagnose with some precision the site and extent of most auditory disorders and to evaluate the proportion of noise-induced hearing loss in each individual affected.
British Journal of Industrial Medicine, Apr. 1972, Vol.29, No.2, p.125-133. Illus. 35 ref.
Occupational health aspects of noise-induced hearing loss
Arbeitsmedizinische Aspekte der Lärmschwerhörigkeit [in German]
Following a review of noise-induced hearing loss trends in the Federal Republic of Germany and of directives for the evaluation of noise exposure for preventive purposes (VDI, ISO), various aspects of medical examinations are discussed: noise-exposure sound-pressure level guides, audiometry and audiogram interpretation, impulse-noise exposure, exposure tests. The tolerance limits of an English standard and an ISO recommendation are discussed. In conclusion, the prophylactic effect of noise-free breaks is considered.
Zeitschrift für Laryngologie, Rhinologie, Otologie und ihre Grenzgebiete, Apr. 1972, Vol.51, No.4, p.203-214. Illus. 28 ref.
Chemin A., Chemin P.
Statistical study of the effects of noise on hearing - a study of the progressiveness of occupational deafness
Etude statistique des effets du bruit sur l'audition - Contribution à l'étude de l'évolutivité de la surdité professionnelle [in French]
440 persons employed in aeronautical factories and exposed to a mean noise level exceeding 85dB were examined at 6-year intervals to determine the course of occupational deafness. Hearing loss was calculated at frequencies of 2000 and 4000Hz and, to estimate the extent of these hearing losses as a function of the subject's age and length of exposure, the results were analysed statistically. Various cases were considered: young subjects exposed to noise for the first time; subjects exposed to noise for several years; and subjects no longer exposed to noise. Aggravation of the condition was clear (the percentage of normal audiograms had fallen over the 6 years from 38 to 18% and the percentage of subjects suffering from a hearing loss of 35-50dB had risen from 17 to 40%); it is concluded from these results that the duration of noise exposure should be limited to 20 years. It is possible that the electrocochleogram would permit better study of hearing loss.
Revue française des affaires sociales, Apr.-June 1972, No.2, p.71-115. Illus. 90 ref.
Noise-induced deafness - A clinical report
Die Lärmschwerhörigkeit - klinisches Referat [in German]
A study of the effects of noise on hearing and the corresponding audiometric effects. Exposure to noise lasting several years produces damage to the external hair cells in the basal turn and the basal part of the middle turn of the cochlea. Pure-tone threshold audiometry reveals a dip in high-frequency perception, and ultra-threshold audiometry shows sensory organ damage. Advice is given on rapid ultrathreshold-audiometry techniques. Criteria are given for the diagnosis of hearing loss due exclusively to noise exposure: hearing loss restricted to the higher frequencies; localisation in the inner ear; proof of injurious exposure to noise.
Zeitschrift für Laryngologie, Rhinologie, Otologie und ihre Grenzgebiete, Apr. 1972, Vol.51, No.4, p.221-230. Illus. 11 ref.
Johansson B., Kylin B., Roepstorff S.
Investigation of noise in the metalworking industry - Part I: Evaluation of the hearing damage risk from exposure to irregular noise. A field and laboratory study
Undersökning av buller i verkstadsindustri - Del I: Bedömning av hörselskaderisk vid exposition för oregelbundet buller. En fält- och laboratoriestudie [in Swedish]
Report on audiometric tests on 170 young workers exposed to non-steady-state work-shop noise. The authors converted the intermittent noise according to ISO Recommendation R 1999 to an equivalent steady-state noise and correlated the results with the audiograms. The correlation showed that hearing damage increases on the average proportionally to noise level. The results also suggest that the conversion method tends to shift the risk limit by about 5 dB towards more tolerable values. In the laboratory, 20 persons with normal hearing were exposed to equivalent levels of steady-state and intermittent industrial noise. The temporary threshold shifts recorded 15 min after exposure showed that intermittent noise, as converted according to the recommended method, produces a lower threshold shift than steady-state noise.
Arbetsmedicinska Institutet, Fack, S-104 01 Stockholm 60, Sweden, June 1972, 18p. Illus. 4 ref.
Temporary threshold shift caused by combined steady-state and impulse noises
Temporary threshold shift (TTS) measurements on 11 subjects, resulting from exposures to steady-state noise, impulse noise, and combinations of both types of noise are reported. 20-min exposures to wide-band steady-state noise at levels comprised between 78 and 96dBA, and impulse noise at levels between 96 and 132dB (peak), and repetition rate of 3.2 pulses/s, were used. When a hazardous level of steady-state noise was combined with various levels of impulse noise, there was a significant reduction in the measured TTS at 4 and 6kHZ. This reduction was greatest when the peak level of the pulse exceeded the r.m.s. level of the steady-state noise by 6-18dB. When a hazardous level of the pulse was combined with several levels of steady-state noise, no significant reduction in TTS was observed. These findings are interpreted as a result of acoustic reflex stimulation; the pulses superimposed on a hazardous steady state noise continually re-activate the reflex and prevent fatigue. The converse does not apply, that is, the non-hazardous (but high-level) steady-state noise does not appear to counteract fatigue resulting from hazardous impulse noise.
Journal of Sound and Vibration, 22 Oct. 1972, Vol.24, No.4, p.493-504. Illus. 11 ref.
Assessment of occupational noise exposure for hearing conservation purposes
Estimation de l'exposition au bruit durant le travail en vue de la protection de l'audition [in French]
The recommendation gives a practical relation between noise exposure, expressed in terms of A-weighted noise level (dBA) and noise duration (40-h working week) and the percentage of people (by age group) that may be expected to show hearing impairment solely as a result of occupational noise exposure. To facilitate the setting of suitable thresholds for noise exposure during working hours, the recommendation proposes a simple noise-measurement method and reproduces the applicable A-weighting correction factors.
International Organization for Standardization, 1-3 rue de Varembé, Genève, Switzerland, May 1971. 11p.
Work in a noisy environment: Judicious distribution of exposure-free periods is of value in a hearing protection programme
Travail dans le bruit, dans un programme de préservation de l'ouïe, une répartition judicieuse de périodes de non-exposition au bruit à sa place [in French]
At above a certain level, noise exposure throughout the work shift entails a hearing acuity hazard. Hearing physiopathologists have found that by interspersing the working shift with exposure-free periods, it is possible to accept higher noise levels over the same duration of exposure without an increase in the hearing damage risk. On the basis of work by Kryter, the author has developed a method for determining the duration and distribution of exposure-free periods. In many cases, this method is less severe than that of the ISO noise rating number and is consequently more acceptable to those in charge of work organisation. However, it is, in general, more severe in the case of high-frequency noise (median frequency band of 2000 Hz).
Archives des maladies professionnelles, June 1972, Vol.33, No.6, p.285-291. Illus. 4 ref.
Hearing supervision in persons exposed to potentially hazardous levels of noise
Die Gehörüberwachung lärmgefährdeter Arbeitnehmer [in German]
Paper read at the 12th Congress on Occupational Safety and Health 1971 in Dusseldorf. The author presents a hearing supervision card for initial and periodical hearing examinations, which meets medical and statistical requirements. This card serves as a data carrier for electronic data processing. It contains questions on medical history, use of hearing protection equipment and occupational noise exposure, and space for the results of a "selective hearing tests". The procedure used for hearing supervision is presented diagramatically. The results of 1511 examinations in 5 iron and steel works using this hearing supervision card are reported. 37% of the persons examined required medical treatment. (For the complete proceedings of this Congress, see CIS 73-373.)
Deutsche Gesellschaft für Arbeitsschutz, Hamburger Allee 26-28, 6 Frankfurt-am-Main 90, Federal Republic of Germany, 1972. p.211-219. Illus.
Reinhold R., Rasche K., Werner W.
High-frequency noise and its effects on man
Hochfrequenter Lärm und seine Wirkung auf den Menschen [in German]
Sound level measurements of noise produced by spinning frames show that ultrasound may be emitted by machinery in cases where ultrasound does not enter into the production process. However, audiometric surveys carried out on personnel operating these frames did not reveal any noticeable temporary hearing impairment after exposure to high-frequency noise.
Zeitschrift für die gesamte Hygiene und ihre Grenzgebiete, July 1972, Vol.18, No.7, p.485-488. Illus. 26 ref.
Scmidek M., Henderson T., Margolis B.
Evaluation of proposed limits for intermittent noise exposures with temporary threshold shift as a criterion
Audiometric investigations were conducted on 36 normal subjects to test the validity of noise exposure standards proposed in the USA for coal-mine operations, as regards intermittent exposures. These standards are intended to prevent permanent hearing loss by prescribing specific limiting combinations of noise levelsnumber of noise exposures and total daily exposure time. 6 intermittent noise exposures, ranging from 15 to 180min, from 109 to 97.5dBA and from 1 to 15 noise bursts, were used in the experiments. Temporary threshold shifts were determined for each exposure at 6 frequencies (500-600Hz). The results indicate that the proposed standards for intermittent noise are deficient in various ways.
American Industrial Hygiene Association Journal, Aug. 1972, Vol.33, No.8, p.543-546. Illus. 3 ref.
The weavers of Dundee
A review of the noise hazard and levels of exposure amongst jute weavers in Dundee, Scotland. A report is given on the examination of 96 subjects with a minimum of 20 years' exposure to noise in jute weaving mills. The mean noise-exposure time to 100dB(A) weaving noise for the group of 96 weavers was 41.6yrs; mean age was 64.7yrs. It was found that these weavers had an average hearing loss of 36.6dB at 0.5, 1 and 2kHz, compared with 12.8dB for matched controls. The main handicap found amongst weavers in this survey was difficulty in speech communication. The problems involved in grading degrees of deafness are discussed.
Transactions of the Society of Occupational Medicine, Apr. 1972, Vol.22, No.2, p.37-43. Illus.
Audiometric testing in accordance with Directive No.2058, page 2 of the Association of German Engineers
Hörprüfungen nach der VDI-Richtlinie 2058, Blatt 2 [in German]
Detailed description of the ear's anatomy and function followed by an explanation of the process of auditory threshold loss. Information is given on audiometric screening. Differentiation between hearing loss due to inner-ear disease and that due to noise exposure necessitates reference to the patient's medical history. The application of a presbycousis-correction factor to audiometric findings is a thorny problem. Inspection of the auditory canal prior to audiometry will indicate the presence of any middle-ear disease and permit the removal of compacted wax. Details are given on the organisation of and procedure for audiometric screening.
Arbeitsschutz, Oct.-Nov. 1972, No.10-11, p.348-352. Illus. 8 ref.
Noise-induced hearing loss in tractor drivers
Lawaaidoofheid bij trekkerbestuurders [in Dutch]
Report on the audiometric examination of 101 agricultural tractor drivers carried out at the instigation of the Netherlands Agronomics and Rationalisation Institute in collaboration with the Netherlands Labour Inspectorate. The results are given in tabular form, accompanied by commentaries. Energetic action to reduce noise levels on tractors and to ensure the use of hearing protection equipment is recommended.
Instituut voor landbouwtechniek en rationalisatie, Mansholtlaan 12, Wageningen, Netherlands, Oct. 1972. 23p. Illus. 12 ref.
Kubík Š., Vladár M.
Dynamics of noise-induced temporary hearing threshold shift increase
Dynamika rastu dočasného posunu sluchového prahu v hluku [in Czech]
Study of the relationship between temporary threshold shift (TTS) and noise-exposure duration (2 and 4h) showed that TTS increase was directly proportional to the rise in sound pressure level and not to exposure duration. Audiometric testing after several hours of exposure does not guarantee correct evaluation of degree of hazard. TTS increase dynamics are the critical factor and must be compared with noise conditions at the workplace.
Pracovní lékařství, Dec. 1971, Vol.23, No.10, p.359-361. Illus. 2 ref.
Direction générale du travail et de l'emploi, sous-direction de l'hygiène et de la sécurité du travail, 2e bureau
Circular T.E. 34/71 of 26 November 1971 concerning the protection of workers from the harmful effects of noise
Circulaire T.E. 34/71 du 26 novembre 1971 concernant la protection des travailleurs contre les effets nuisibles des bruits [in French]
Technical commentary on French Decree No. 69-348 of 12 April 1969. Individual sections are devoted to: noise characteristics; measurement and analysis of noise and its effects on hearing (noise level measurement, noise level contours, audiometry); noise control measures (group and personal protection, medical supervision). Appendices contain: the recommendations of the Technical Noise-Study Committee of the French Ministry of Public Health indicating acceptable levels of industrial noise, noise danger limits, and worker audiometry. The circular was published in "Journal officiel de la République française" of 25 January 1972.
Cahiers de notes documentaires - Sécurité et hygiène du travail, 2nd quarter 1972, No.67, Note No.793-67-72, p.205-215.
Batolska A., Begov A.
Ultrasound and the hearing system
Ultrazvuk i sluh [in Bulgarian]
Low levels of ultrasound accelerate the normal biological processes, and high levels produce protoplasmic cellular lesions due to mechanical and chemical factors (vacuolisation and tissue necrosis). Study of hearing and certain biological indices in 41 subjects exposed to ultra-sound, broken down into groups by age and duration of exposure, showed that the most frequent complaints were tinnitus and reduced auditory acuity. After the day's work, the audiogram curve increased 50dB for high frequencies, remained stationary for medium frequencies and increased only insignificantly for the low frequencies. These changes vary between individuals and in some cases may be absent. No changes in erythrocyte haemoglobin content were found. In more than one-third of the subjects there was a tendency to acid haemolysis. In a number of cases there was a fall in reduced glutathion which is attributed to erythrocyte fragility. No clear correlation was found between biochemical indices and temporary hearing disorders.
Naučni trudove na NIOTPZ - Razdel uši-nos-gărlo i stomatologija, 1970, Vol.18, p.18-22. Illus. 8 ref.
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