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PubMed1990

Evaluation of the exposure of a merchant ship crew to mechanical vibration during a sea voyage.

Vibration levels were measured on a Roll-on/Roll-off type ship, during her voyage, with the use of Bruel and Kjaer equipment. The calculated equivalent values of mechanical vibration accelerations for various workplaces and for living quarters did not exceed the acceptable levels, according to Polish hygienic standards for border values of comfort of work. The intensity of vibration in selected places was generally determined by longitudinal vibration. The prevailing frequency was 8 Hz.

Humans↗
PubMed1990

[Results of psychometric and questionnaire methods in the evaluation of noise and vibration on floating oil rigs in the Caspian sea].

A psychometric study of noise and vibration was performed at different parts of the Caspian floating oil rigs. The analysis of 500 questionnaires received from the personnel showed that the correlation coefficients for different values, depending on the parameters of the levels, were 0.71-0.87 for noise and 0.33-0.44 for vibration. The noise levels calculated for oil workers of different professions, were: in cabins, recreation rooms and working sites 40-52, 57-63 and 73-74 dBA respectively, and the comparative vibration rate levels were 67-74, 79-85 and 90-97 dB, respectively. 273 questionnaires revealed that the acoustic conditions in the abins affected both the process of falling asleep and depth of sleep (correlation coefficients 0.88 and 0.93, respectively). Noise levels at 30-36 dBA did not cause any sleep discomfort. 84% questionnaires contained in average 3.5 complaints, with the maximum 5.2 complaints for the machine operators, and the minimum 3.2 complaints for the electricians who worked in acoustically more favorable conditions. The study proved that the psychometric and questionnaire data in 70% cases corresponded to the results of the laboratory techniques, such as audiometry, chronoreflexometry, tono- and pulsometry, electrocardiometry, etc. The research data received served a basis for noise and vibration hygienic norming in floating oil-rig sites.

Humans↗
PubMed1990

[Clinico-echocardiographic studies of the state of the heart in vibration disease].

Established was the rate of interventricular septum asymmetrical hypertrophy and left auricle exstasia in vibration disease patients as a result of local vibration. The left ventricle myocardium contraction in major parameters (ventricular ejection, maximum ejection, ejection time and volume, the myocardium circular contraction rate and anterior-posterior contraction, systolic ejection rate) were not affected to a significant degree. The left ventricular systolic function was tending to decrease in vibration disease cases combined with IHD and AH. Desirability of using EchoCG in combination with load testing was proposed for the differential diagnosis of metabolic coronary lesions of the myocardium in vibration disease patients.

Adult↗
PubMed1990

Hand-arm vibration, noise, temperature and static load--an experimental study of peripheral circulation while operating chain-saws.

From the viewpoint of elucidating the etiological mechanism of vibration-induced white finger (VWF), a model experiment was designed using a chain-saw under laboratory conditions. Finger skin temperature and finger blood flow were measured simultaneously as indicators of peripheral circulatory movement, using a thermister and an apparatus for measuring tissue blood flow based on the thermal diffusion method. In the first project (Experiment A), five healthy subjects operated a chain-saw at a high working speed with-out actually cutting anything. In the second project (Experiment B), seven healthy subjects were exposed to three different kinds of experiments with combinations of hand-arm vibration, noise and tool weight at about 15 degrees C room temperature. In the third project (Experiment C), the effects of tool weight and grip force were examined. In the fourth project (Experiment D), patients suffering from vibration disease were exposed to hand-arm vibration and the noise of a chain-saw for 2 minutes. In experiment A, the mean value of the normalized finger skin temperature decreased gradually with cyclic changes corresponding to each exposure and break period. Changes in finger blood flow had almost the same pattern as the changes of skin temperature, but the recovery of blood flow during a 30 sec break period was notable and a slight elevation of the base line was observed. In experiment B, the mean value for the normalized finger skin temperature decreased much more when the subjects operated a chain-saw at a high working speed than when they operated the chain-saw with the noise isolated by double hearing protection. On the other hand, the results obtained in experiment C indicated that the effect of tool weight should be considered as an important factor for investigating the acute changes in peripheral circulation. In experiment D, some patients showed an unusual pattern in the change of blood flow during a post exposure period which was not seen in healthy subjects.

Adult↗
PubMed1989

[Experimental HFV apparatus utilizing a mechanical vibration].

We make an experimental HFV apparatus in which the mass-spring system is utilized as the vibration actuator. When this apparatus is operated near the characteristic frequency of the mechanical vibration system, the efficiency is quite good and trivial motor is enough to realize the vibrating flow for the experimental ventilator. In this paper we first investigate the flow-frequency relations and found that above the characteristic frequency of the mechanical vibration system the oscillating volume of flow is nearly constant. Next we check the gas exchange between model-lung and atmosphere and obtain the relations among pressure vs. flow rate, pressure vs. rate of gas exchange.

High-Frequency Ventilation↗
PubMed1989

[The effect of vibration on the impulse activity of cortical neurons and their reaction to stimulation of the posterior hypothalamus and Deiters' vestibular nucleus].

The effect of vibration on spontaneous unit activity, oxygen consumption in cortical neurons and their responses to stimulation of posterior hypothalamus and vestibular Deiters' nucleus, were studied. Biphasic changes occurred in frequency of cortical unit activity and in the latter interrelationships with the level of oxygen consumption after 3-hour exposure to the vibration. The 15-day vibration enhanced the mean frequency of unit activity, facilitated the effect of subcortical neurons and eliminated bursts of discharges. The effect of long-term vibration upon cortical unit activity response to stimulation of subcortical structures was quite obvious.

Animals↗
PubMed1989

[Analysis of Raynaud's phenomenon in systemic scleroderma: comparative study with that in vibration disease].

Raynaud's phenomenon in systemic scleroderma (SD: 37 cases) was analysed and compared with that of vibration disease (VD: 21 cases) in order to clarify the entity of SD. Raynaud's phenomenon was provoked by cold exposure, high temperature (hot water) exposure, mental stress and vibration stress, which were seen in 37 cases, 22 cases, 7 cases and 3 cases of SD, respectively. However, in VD patients, 21 cases were provoked only by cold exposure other than for vibration stress (1 case). Raynaud's phenomena in SD and VD patients differed in appearance duration, and color changes. These data lead to the conclusion that the vascular responses of SD for extrinsic factors including vibration stress and cold exposure may be different from those of VD.

Adolescent↗
PubMed1989

[An evaluation of the vibration hazard of the hand-operated machines used in automobile manufacture].

After the examination and hygienic assessment of 53 types of hand-held Soviet and foreign machines, 30 types of them were selected because according to their vibration and ergonomic characteristics they could be recommended for wide application in automotive industry. Some causes for deterioration of vibration characteristics of hand-held machines while they were in use were analyzed. Among the basic causes there were untimely running, preventive repair and vibration parameters control of the machines and also their mishandling. Introduction of the proposed pattern of machine movement and maintenance during their use could further the improvement of the technical state of hand-held machines and decrease of local vibration levels affecting workers.

Automobiles↗
PubMed1989

[Research on the dose-response relationship of hand transmitted vibration and its hygienic standard].

According to ISO 5349-1986, the akw(4) was 9.04-41.47m/s2 which was measured and calculated in 5 types of instruments: chain saw, cleaner, rock driller, riveter & emery wheel. There were 170 cases with white finger through epidemiologic investigation on 5 types of workers in 1,675 persons. Based on the work mentioned above, a formula, which represented worker cumulative exposure to vibration was deduced: D = [(a2kw(4).T)1/2.Y.d]2 Furthermore, the dose-response relationship of hand transmitted vibration and prevalence of white finger was computed, the regression equation was: P = 1.0904X - 6.214 2 Under precondition of exposure to vibration for 20 years with 90% of workers having no white fingers, the limit of hygienic standard of hand transmitted vibration in china should be set at 4 hours and as akw(4) less than or equal to 5 m/s2 based on the regression equation.

Fingers↗
PubMed1989

Sensory thresholds among construction trade painters: a cross-sectional study using new methods for measuring temperature and vibration sensitivity.

Instruments that measure quantitatively sensory threshold to vibration and temperature difference were used to test 93 construction trade painters and a reference group of 105 healthy construction and industrial workers who were not painters. A "forced-choice" testing procedure, and an algorithm for threshold estimation (the "Best PEST"), was used for the Temperature Sensitivity Tester and the Vibratron. The method of limits procedure was used for the Biothesiometer. When measured with the Vibratron, painters in the older age stratum were found to have significantly higher vibration thresholds than the reference group. Painters had significantly more temperature sensitivity thresholds classified as "high" than the reference group. Among painters, exposure intensity and cumulative exposure over the past year was positively associated with vibration thresholds estimated using the Vibratron. Lifetime cumulative exposure, cumulative exposure over the previous month, and exposure intensity were positively associated with vibration thresholds estimated using the Biothesiometer.

Adult↗
PubMed1986

Clinical aspects of the hand-arm vibration syndrome. A review.

At present it seems likely that the different components of the hand-arm vibration syndrome, eg, vibration-induced white finger (VWF), numbing of the hands and arms, muscular fatigue, and occasionally prevalent bone degeneration, may arise independently, and therefore they should be evaluated separately. Evidence of changes caused in the autonomic nervous functions of the body by local vibration is not conclusive. The vascular history should be confirmed objectively with a cold provocation test under laboratory conditions. In individual diagnostics it is useful to record (with modern plethysmographic techniques) the recovery of digital temperature, digital blood pressure, and flow after local cooling. Vibrotactile perception measurement seems to be suitable for group diagnosis. Much of the diagnostic weight for VWF can be obtained from accurate case histories, although, for early changes, the history may be atypical. The lack of simple objective tests for evaluating the hand-arm vibration syndrome makes it difficult to, eg, confirm the history of its different components objectively and estimate the extent of the disability it causes.

Humans↗
PubMed1987

[Electrophysiologic study of reticulo-limbic relations during long-term exposure to vibration].

In chronic experiments on rabbits with implanted electrodes, the 3-month vibration induced phasic changes of the spontaneous electrical activity (EEG) of the dorsal hippocampus (area CA3), mesencephalic RF, some regions of the neocortex and of reticulo-cortical EPs. After the ist month of 3-hour daily vibration, an activation in the EEG and increase of the amplitude of reticulo-cortical EPs more obvious in the neocortex, were found. The 3-month vibration exerted an inhibitory influence on reticulo-cortical system as expressed by slow waves prevailing in the EEG of cortical and subcortical structures, decrease of the MRF excitability, as well as by an increase of the latency and decrease of the amplitude of the EP positive wave, reduction of the amplitude of its negative phase. The physiological mechanisms of the vibration pathology are discussed.

Animals↗
PubMed1986

[Rheography of the upper extremity in the diagnosis of vibration-induced vascular disorders].

The possibilities of impedance rheography in the diagnosis of the vascular form of the vibration syndrome have been presented. Three groups have been covered by the investigation: controls, subjects in occupational significant exposure to local vibration and subjects with the diagnosed vascular vibration syndrome. The rheographic investigations have been carried out synchronically from the area of hand fingers and forearms as well as under a positional test (arm elevation). Analysis of the relative pulse rate accounts for differentiating workers in the test groups. The findings confirm that the methods applied in the rheographic investigations may be a practical importance in the diagnosis of the vibration syndrome.

Adult↗
PubMed1987

Intensity judgments of vibrations in the Y axis, Z axis, and Y-plus-Z axes.

Seated subjects matched their perceptions of the intensity of Y-axis, Z-axis, or Y-plus-Z vibrations, by adjusting the intensity of a sinusoidal, 5-Hz, X-axis response vibration. Stimuli were sinusoidal at 3.2, 5, and 8 Hz. For each frequency there were six vibration conditions (Y axis alone, Z axis alone, or both axes together with 0 degrees, 90 degrees, 180 degrees, or 270 degrees phase angles between them) presented at each of two acceleration levels (0.15 and 0.25 G R.M.S.). Results showed that X-axis response accelerations for the dual-axis stimuli were greater than those for either one of their Y-axis or Z-axis components. This occurred for both acceleration levels and for all three frequencies. In addition, response acceleration was nearly constant for the dual-axis stimuli regardless of the phase angle between their Y-axis and Z-axis components. Again, this was true for both acceleration levels and all three frequencies. These findings indicate that although dual-axis vibrations are judged to have greater subjective intensity than either of their single-axis components the phase relationship between those components appears to have no appreciable effect.

Acceleration↗
PubMed1986

[Adrenergic innervation of the myocardium and skeletal musculature of the rabbit exposed to vibration].

Innervation of the myocardium and that of foreleg musculature has been studied in rabbits subjected to the local vibration effect. The point where the vibration is applied is the foreleg, because its nerve plexuses are in the tightest way connected with the cardiac nervous apparatus. For treatment of the sections incubation in 2% solution of glyoxylic acid is used, which is followed with luminescent microscopy. While studying adrenergic nerve plexuses of the right auricle, their luminescent activity is stated to decrease more than by a half. In the ventricles only single perivascular adrenergic nerve plexuses remain. A constant reaction of the plexuses mentioned is revealed not only in the right, but in the left extremity subjected to a direct vibration. Taking into account that the vibrational effect is performed as a generalized action and it embraces the whole skeleton of the animal, it is possible to suggest that the activity of the sympathetic nervous plexuses results in a constant influence of noradrenaline on the wall of blood vessels producing their steady spasmodicity.

Adrenergic Fibers↗
PubMed1986

Assessment of vibration white finger syndrome.

The degree of Raynaud's phenomenon due to the use of vibrating tools is difficult to assess because of the episodic nature of the attacks and the paucity of vascular and neurologic signs between attacks. Ninety-two loggers, miners and other workers using vibrating tools and experiencing Raynaud's phenomenon were examined at the Vancouver General Hospital between 1982 and 1985. Details of history, symptoms and occupation were obtained. The majority of workers had loss of sensation in their hands to pinprick, and the extent of this correlated closely with the severity of symptoms, a correlation not previously described. In 16 subjects the loss of sensation was proximal to the level of symptoms, in 50 at the same level and in 23 distal. In three the correlation was unknown. The severity of the vibration white finger syndrome was assessed using the classification of Taylor. Four workers were placed in stage 1 (occasional blanching of fingertips, with or without tingling or numbness), 30 in stage 2 (blanching of one or more fingers with numbness in cold weather), 36 in stage 3 (frequent finger blanching affecting most digits) and 22 in stage 4 (as stage 3 but symptoms so severe that manual work is difficult and vibrating tools cannot be used). The correlation of symptoms with loss of sensation to pinprick was useful in assessing the severity of the syndrome and in the classifying of claimants for Workers' Compensation Boards.

Adult↗
PubMed1986

The diagnostic potential of vibration arthrography.

The detection and interpretation of vibration emission from the locomotor system is a sensitive, noninvasive method for the objective study of human joints. The projects reviewed here aimed to identify and categorize vibration signals from various joints, chiefly the neonatal hip and the adult knee. Using a vibration detection and computerized analysis system, various studies have suggested that vibration arthrography will be a potentially valuable diagnostic service for the orthopedic surgeon of the 1990s.

Auscultation↗
PubMed1986

Effect of vibration on force sensation in fatigued muscle.

Nine subjects did repeated maximal voluntary contractions (MVCs) of the right knee extensors to induce fatigue. At regular intervals during this process, they matched the force of a 50% MVC in the fatiguing right muscle with a contraction of the unfatigued left muscle that felt like the same force. Perturbations in force sensation were achieved by applying high-frequency vibration (160 Hz) to the patellar tendon of the fatigued muscle during one of a pair of 50% MVCs. The neural drive to the muscle was monitored from the surface electromyogram. Cycles of 10 fatiguing contractions followed by 2 matching contractions were repeated until the subjects could no longer produce 50% of the initial MVC or until they chose to stop. On the average, MVC force fell to 68% of its initial value by the end of 50 fatiguing contractions; almost all of the force loss occurred after completing the first 20 contractions. Maximal electromyograms declined proportionally, and percutaneous shocks delivered during fatiguing contractions did not produce a measurable twitch. This indicated that there was no central fatigue and that force loss was due to failure of the contractile apparatus. In the non-vibrated trials, force sensation increased as a mirror image of force loss. Vibration increased force sensation in the fresh muscle but the effect of vibration disappeared in fatiguing contractions. These data suggest that the sensory analog of muscular fatigue is not necessarily a consequence of alterations in peripheral receptors but may also reside in the central nervous system.

Action Potentials↗