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PubMed1986

[Human response to vibration. An ergonomic applicability of current knowledge to the automobile].

With technological progress, vibrations as a risk factor for health have now extended beyond the boundaries of the workplace to become a social rather than an occupational risk. Now that we know the local or general damage vibrations can cause, ergonomists and occupational health officers are increasingly involved in the preparation of techniques for the application of their knowledge to preventive measures. Apparently, negative reactions derive form the impact on sensorial structures that develop very slowly with completely new sensorial stimuli. The acoustic and chronic effects of middle frequency vibration on various parts of the body are described both in experimental conditions and on a particular group of workers. Given the complexity of the vibration in human system interaction it is naturally extremely difficult to establish a universally valid scientific criteria to assess the response of the human body. These limitations expressly declared in the ISO 2631 guide are also implicit in the other regulations proposed. Having re-emphasised the need for research that is more relevant to application demands especially in car production, preventive medicine suggests that responses may be more adequately assessed by the application of new instrumental diagnostic techniques and the comparison of data on a vast scale.

Automobile Driving↗
PubMed1985

Influences of neck vibration on lower limb extensor muscles in man.

The effects of neck vibration were studied in ten healthy subjects standing in unrestrained or restrained conditions. An involuntary slow and gradual displacement of the body axis associated with a subjective experience of forward tilt occurred during vibration of the dorsal surface of the neck. This effect was associated with a decreased tonic contration of the antigravitary lower limb musculature. The amplitude of the H-reflex from the soleus muscle, recorded at progressively increasing time interval after the onset of the vibratory stimulus, showed complex interactions: in particular, in unrestrained conditions an early inhibitory phase occurred at about 100 msec, followed by a short-lasting facilitatory phase between 150-300 msec and by a late long-lasting excitatory component which started 500-600 msec after the onset of vibratory stimulus. In restrained subjects, the late excitatory phase disappeared and was substituted by a delayed depression. In this instance, the short-lasting facilitatory phase appeared to be superimposed on a background of inhibition. The effects produced by the neck input on the H-reflex were attenuated during vibration of the dorsal muscolature at L4-L5. The mechanisms involved in the cervical control of posture and reflex movements following neck vibration are discussed.

Adult↗
PubMed1979

[Blood coagulation system in workers exposed to noise and vibration].

The authors examined the blood coagulation system in the following 3 groups of workers occupationally exposed to noise and vibration: A--those in whom the examination was conducted 7--16 hrs after finishing the work, B--those in whom the examination was conducted at the 3rd or 4th hour of work, and C--those suffering from angioneurosis of the vibration syndrome of II or III period who have not been exposed to vibration for some recent years. These investigations indicated the lack of blood equilibrium tending to hypercoagulability, shortened duration of plasma recalcination, increased elasticity coefficient of mE thromboelastogram coagulation, increased fibrinogen concentration; these changes were most evident in the group with advanced vibration disease and in those in whom the examination was conducted at their working time. Fibrinolysis duration was significantly prolonged during work, and shortened in those with advanced angioneurosis. In the opinion of the authors, those disturbances in the blood equilibrium system may be accounted for by the conformation changes of proteins.

Adult↗
PubMed1978

Model for human controller performance in vibration environments.

A model has been developed to predict biomechanical response and human controller performance as a function of vibration environment and tracking-task parameters. The model consists of three major elements: 1) a biodynamic model to predict limb and body motion resulting from platform vibration, 2) a pilot/vehicle model to predict tracking performance, and 3) an interface model to relate changes in certain pilot-related model parameters to biodynamic response. Linearity of biodynamic response mechanisms is demonstrated, and the model is shown to predict accurately the effects of tracking performance of vibration amplitude and spectrum, control gain, R.M.S. tracking input, and direction of vibration input.

Aviation↗
PubMed1983

Respiration maintained by externally applied vibration and tracheal insufflation in the cat.

It was reported recently that adequate gas exchange could be maintained in patients and experimental animals by applying very high-frequency (15 Hz), low-volume oscillations at the upper airways. This report deals with a new mode of high-frequency ventilation, in which gas exchange is achieved in paralyzed cats by externally vibrating the chest wall. These vibrations, which alone caused very small-volume (less than 0.5 ml) oscillations at the tracheal opening, maintained gas exchange at normal PaCO2 for hours when coupled with tracheal air insufflation. PaCO2 values as low as 15 torr could be achieved by increasing the insufflation rate. Vibration frequencies in the range of 20-45 Hz were equally effective. The method required little or no continuous positive airway pressure, caused little elevation of mean tracheal pressure, and no consistent changes in arterial and central venous pressures during ventilation. In addition to the potential merits of this method of ventilation, the described vibrations seem to considerably reduce the anatomic dead space and as such may assist conventional methods of artificial ventilation or even spontaneous breathing when rapid and shallow.

Animals↗
PubMed1983

The effect of mechanical vibration and industrial noise on the behaviour of blood serum immunoglobulins and on the lymphocyte blastic transformation.

The investigations have been undertaken to determine the effect of mechanical vibration on the behaviour of blood serum immunoglobulins and on the lymphocyte blastic transformation. The concentrations of IgA, IgG, IgM have been determined with 174 workers of metallurgical plants who were exposed to both vibration and noise, and with 50 workers exposed to noise only. The lymphocyte blastic transformation has been determined with 70 workers exposed to both vibration and noise. The investigations revealed that mechanical vibrations cause the concentration of IgA and IgG to increase, and that of IgM - to decrease; they also stimulate the lymphocyte blastic transformation. The noise itself causes the level of the examined immunoglobulins to lower.

Adult↗
PubMed1984

Benefits of helmet-mounted display image stabilisation under whole-body vibration.

The effects of whole-body vertical vibration in the range 2.5-25 Hz on visual performance with two types of raster scan helmet-mounted display have been determined. The benefit of an image stabilisation system on numeral reading performance during vibration was also assessed with both display systems. Increases in mean reading time of over 130%/m . s-2 R.M.S. and increases in percentage reading error of more than 30%/m . s-2 R.M.S. were recorded with unstabilised displays. With vertical and horizontal image stabilisation, these decrements in performance were reduced to less than 40%/m . s-2 R.M.S. increase in reading time and less than 10%/m . s-2 R.M.S. increase in reading error. Data on the transmission of vibration from the seat to the head and from the head to the helmet were also obtained. These indicate a relation between biodynamic behaviour and visual performance during vibration.

Biomedical Engineering↗
PubMed1983

[Electrocardiographic examination of the heart and the study of catecholamine secretion in workers subjected to mechanical vibration and occupational noise].

Electrocardiographic tests in 281 workers of metallurgical industry, exposed for 3-20 years to mechanical and acoustic vibrations exceeding allowable standards, were carried out. The control group consisted of 120 subjects unexposed to physical or chemical hazards. In 82 subjects exposed to vibration and noise, 43 workers exposed to isolated noise and 30 subjects of the control group, the amount of 3 methoxy--4 hydroxymandelic (3M4HM) acid before and after work was determined. Significantly more frequent repolarization disturbances of neurovegetative nature (V-3), particularly in those simultaneously exposed to general and local vibration, were evidenced. In those exposed exclusively to noise no ECG changes were found. In addition, increased 3M4HM secretion, due to both local and whole--body transmitted vibration, was found. Isolated noise does not induce an increase in 3M4HM secretion.

Adult↗
PubMed1980

Combined effects of broadband noise and complex waveform vibration on cognitive performance.

The performance of 12 subjects was measured on a Complex Counting Task during exposure to each of four experimental conditions for a duration of 30 min. Two levels of noise, 65 dBA and 100 dBA, were presented both with and without 0.36 R.M.S. Gz sum-of-sines vibration. Combined 100 dBA noise and vibration produced less adverse effects than the vibration combined with 65 dBA noise. This result agrees with out previous studies using tracking tasks. However, two effects were demonstrated that had not been obtained previously. First, a clearcut adverse effect of vibration on the Counting Task was obtained. Second, an adverse effect of 100 dBA noise on the counting task was demonstrated. Previously, a 110 dBA noise was required to adversely affect tracking performance.

Adult↗
PubMed1978

[Voice and vibration sensations in the speech forming organs: clinical and theoretical aspects of rare symptoms specific for schizophrenia].

When studying 750 psychiatric in-patients with psychoses of various diagnostic groups, the symptoms of voice sensations and vibration feelings could only be found among patients with paranoid schizophrenia. In addition, these symptoms were located exclusively in body areas that are involved in the peripheral motor production of voice and speech (areas of head, throat, thorax). In 11 of 15 such cases that could be identified, the sensations of voices and vibrations occurred simultaneously and in identical body parts; in the remaining 4 cases only voices without vibration sensations were reported. Therefore these symptoms can be considered as highly specific for schizophrenia. According to the terminology of Bleuler these two symptoms are because of their rareness to be taken as accessoric symptoms; according to the terminology of Kurt Schneider they have the value of first rank symptoms because of their highly diagnostic specifity for schizophrenia. The pathogenesis of these symptoms is on the one hand discussed under the perspective of language development and the changing function of language for behaviour control; on the other hand, the pathogenesis of these symptoms is discussed from the viewpoint of cybernetic, or neurophysiological-neuroanatomical foundation of speech production and speech control. Both models of explanation have in common that the ideational component of speech is noticed as acustic halluzinations and the motor proprioceptive part of speech is noticed as sensation of vibrations, both in a typically schiphrenic manner, i.e. dissociated and ego-alienated.

Adult↗
PubMed1995

Noise and vibration load of lumbermen.

At eight lumbering sites in Slovenia the noise load of lumbermen working with new and used motor saws was investigated by noise measurements at the ear level. A major contribution to the noise load (Leqv = 96-100 dB(A) came from motor saw operations such as limbing. Lumbermen are overloaded with interrupted noise for 25 per cent of their working time. The noise produced by a used motor saw exceeds the noise coming from a new one by 0.7 dB(A). Results of a pilot research into the lumbermen's vibration load generated by Husqvarna 266 and 254 motor saws are also presented. The measurements involved three cutting sites and four lumbermen for six days. The vibration load during the working hours ranged between 6.6 and 10.8 m/s-2. Owing to the fact that vibrations are interrupted and the exposure does not last throughout the working day, the vibration load does not reach a level which would be detrimental to lumbermen's health.

Humans↗
PubMed1994

[The evaluation of the working conditions and the characteristics of the prevalence of vibration-induced disease among miners in the Far North].

The article covers the data of physiologic and hygienic evaluation of vibration disease prevalence among miners of Far North and evaluation of their work conditions. The authors compare effects of local vibration on miners in the mines with negative ambient temperatures during the year and in those with the low positive temperatures. The negative temperatures and local vibration appeared to disorder formation of specific physiologic response to the stated factors. The data presented cover prevalence and progressing of vibration disease among the miners in Far North.

Adult↗
PubMed1994

[Determination of finger vibrotactile threshold and its significance in patients with hand-arm vibration syndrome].

Vibrotactile sense threshold (VST) of the end of the middle fingers in 97 patients with established or suspected hand-arm vibration syndrome and 60 healthy controls was determined, and finger VST contour and vibration damage curve were plotted. Results revealed the most sensitive frequencies of VST were 8 Hz for the patients and 125 Hz for the controls, respectively. VST in the patients with hand-arm vibration syndrome was higher than that in the controls, and the threshold shift was initially at high frequency with a "V" dip at 125 Hz and 250 Hz. So, the authors think determination of VST is an auxiliary method used for diagnosis of hand-arm vibration syndrome.

Adult↗
PubMed1994

Perfusion defects in vibration white finger: a clinical assessment using isotope limb blood flow.

Vibration white finger is a vasospastic disorder caused by long-term exposure to vibration tools. In an attempt to assess the extent of obliterative vessel disease in this disorder, hyperaemic hand blood flow was measured using technetium-labelled human albumin and a gamma camera. This method quantitates blood flow in ml/100 ml of tissue per min in addition to providing a perfusion image used to assess vessel disease. A perfusion score is then given to this image to reflect the extent of disease. The results of this study demonstrate that 78% of patients with vibration white finger had evidence of organic vessel disease. Moreover, patients with advanced disease tend to be bilaterally affected. The use of this simple method is advocated to aid in the diagnosis of vibration white finger; this may be particularly important for medicolegal purposes.

Adult↗
PubMed1993

[Glucose tolerance test and insulinemia in workers occupationally exposed to vibration and noise].

Oral glucose test and serum insulin determination was performed in 192 workers of a large metallurgical factory. The subjects were divided into four groups: 1. exposed to isolated noise, 2. exposed to local vibration, 3. exposed to the whole body vibration, and 4. control group. In the group exposed to the whole body vibration more frequent occurrence of higher glucose and serum insulin concentrations were found when compared with the control group. The observed changes were caused by low and medium frequency of the whole body vibration.

Adult↗
PubMedDate not supplied

[The risk of vibrations to the hand-arm system and cumulative trauma disorders in shoe manufacturing: a clinical case report].

The article reports the case of a woman working in a shoe factory who had been using vibrating tools for 5 years. Because of paresthesia in her left hand, in 1989 she underwent various diagnostic trials that revealed an initial carpal tunnel syndrome of the left wrist and a homolateral epicondylitis. Measurement of the vibrations transmitted to the hand from the vibrating tool confirmed the probability of a high risk of exposure for the hand-arm system. Such adverse effects have been described by British authors as "cumulative trauma disorders" and were confirmed in this study. The importance of further studies aimed at estimating the type and degree of exposure to vibrations in shoe manufacturing workers is stressed.

Carpal Tunnel Syndrome↗
PubMed1993

Low-frequency vibration emitted from unstable hip in human neonate.

Developmental dysplasia of the hip (DDH) continues to be an orthopedic enigma. Some authors still believe it is a purely birth phenomenon. Even with widespread birth screening, however, DDH continues to become evident later than three months of age, long after a satisfactory outcome can be guaranteed. In an effort to reduce the number of late manifestations, the authors have developed a noninvasive form of screening for DDH called vibration arthrometry. Five hundred neonates were examined in local maternity hospitals, according to the guidelines of Ortolani and Barlow. The new method involves the attachment of miniature accelerometers around the infant's pelvis. Using this method, it was possible to elicit vibration events from approximately one fourth (255 hips) of the hips tested; vibrations were recorded from normal hips (125), from "clicky" hips (128), and from unstable hips (two). Differences between "nil-felt" (clinically silent) and "click-felt" (palpable clicking on testing) were significant. Vibration testing can be seen as an aid in the manual palpation necessary to detect this crippling condition.

Female↗
PubMed1993

[Methods for palestesiometric measurement in workers exposed to local vibration].

The paper discusses methodology for the vibration perception measurement as well as specifies the mean values and standard deviation of the vibration perception threshold in people not exposed to vibration. The increase of the threshold level of vibration perception in chain-saw operators, chippers and grinders has also been analysed.

Humans↗