Symptoms Of Vibration-induced White Finger Research Articles

Landsbergis, Johanning, Stillo Respond to Letter to the Editor.

Landsbergis, Johanning, Stillo Respond to Letter to the Editor.

Work disability after diagnosis of hand-arm vibration syndrome.

Our aim was to study the course of vasospastic and sensorineural symptoms after the clinical diagnosis of hand-arm vibration syndrome (HAVS), and the association of current HAVS symptoms with occupational status, self-evaluation of health, quality of life, and work ability. We gathered all HAVS cases diagnosed at the Finnish Institute of Occupational Health in Helsinki and Tampere during 1990-2008. A questionnaire was sent to all these patients (n = 241). Altogether 149 of them (62 %) returned the questionnaire. Cumulative lifelong vibration exposure was evaluated on the basis of the data in the patient files. On average, 8.5 years after the diagnosis of HAVS, approximately one-third of the patients reported improvement in symptoms of vibration-induced white finger (VWF) and the sensorineural symptoms. Young age and shorter exposure time were associated with improvement in VWF symptoms (p = 0.033 and p < 0.001, respectively). Persistent or deteriorated symptoms of both VWF and sensorineural symptoms were associated with lowered work ability, quality of life (EQ-5D), and general health, also after adjusting for age, smoking, and diseases other than HAVS. The patients' own prediction of work ability in 2 years was more negative if the VWF symptoms or sensorineural symptoms had continued after diagnosis of HAVS (p = 0.065 and p = 0.001, respectively). Our results suggest that in about two-thirds of the patients, the HAVS symptoms may stabilize or deteriorate in the follow-up. Considering the effects on work ability, timely prevention measures should be taken more actively to help patients continue their working careers.

A follow up study of vibration induced white finger in compensation claimants

Aims: To follow up vibration induced white finger (VWF) in a selected group of 73 vibration exposed workers who claimed unsuccessfully for VWF compensation at a first examination. Methods: The...

Interpretation of the finger skin temperature response to cold provocation.

To compare alternative methods of interpreting the response of finger skin temperature (FST) to cold provocation for the detection of the abnormal cold response observed in vibration-induced white finger (VWF). The FST response to cold provocation was measured in 36 male subjects: 12 office workers, 12 manual workers and 12 manual workers with symptoms of VWF. The FSTs were monitored continuously on the distal phalanges of all five fingers of a test hand for 2 min before, for 5 min during, and for 10 min following, immersion of the test hand in water at 15 degrees C. Of the fingers investigated, 147 were reported not to exhibit blanching and 33 were reported to exhibit blanching. Twenty-one alternative methods of interpreting the response of FSTs to cold provocation were assessed. These were grouped as: (1) areas above the response profile (i.e. the area above the curve showing the FSTs as a function of time during cooling and recovery), (2) areas below the response profile, (3) absolute temperatures during and following cold provocation, (4) percentage differences in FSTs, (5) the times taken for FSTs to rise by specified amounts and (6) rates of change of FSTs. Differences in the response to cooling between those fingers reported to blanch and the fingers not reported to blanch were tested, and receiver operating characteristics (ROCs) were used to compare the sensitivity and specificity of the various measures to symptoms of VWF. The areas above the response profile, areas below the response profile, percentage FSTs, absolute FSTs and rates of change of FSTs tended to discriminate between healthy and unhealthy subjects on a group basis. However, some of these methods of interpreting the FST response to cold provocation did not show a high sensitivity or specificity to vascular dysfunction on individual fingers. The area above the response profile, the percentage of initial temperature at the fifth minute of recovery and the maximum temperature during the 10-min recovery period, were found to show the highest sensitivity and specificity to symptoms of vascular dysfunction. The method chosen to interpret the FST response to cold provocation affects the ability of the test to detect an abnormal cold response. The area above the response profile, the percentage of initial temperature at the fifth minute of recovery and the maximum temperature achieved during a 10-min recovery period appear to be the most suitable measures for monitoring vascular function in workers exposed to hand-transmitted vibration. It is suggested that the FST response to cold provocation should be interpreted with respect to the state of initial blood flow.

A prospective study of the cold response of digital vessels in forestry workers exposed to saw vibration.

To investigate the occurrence of vibration-induced white finger (VWF) and the cold response of digital vessels in a group of 68 forestry workers who underwent a first clinical examination in 1990 and were then reexamined in 1995. The forestry workers were divided into three groups: group A (n = 27), active workers who did not have VWF in 1990 and continued to use chain saws; group B (n = 29), workers who did not have VWF in 1990 and retired before 1995; and group C (n = 12), active or retired workers who had VWF in 1990. The subjects underwent a medical interview, a complete physical examination, and a cold provocation test, which were performed by the same physicians at both surveys. The cold test consisted of measurement of the finger systolic blood pressure (FSBP) after local cooling to 10 degrees C, expressed as a percentage of the pressure recorded at 30 degrees C (FSBP%10 degrees). Three new cases of VWF occurred during the follow-up period among workers who had used only antivibration (AV) chain saws. The vasoconstrictor response to cold was unchanged in group A and improved in group B (P < 0.001). A significant decrease in VWF symptoms and abnormal response to cold was observed in group C (P < 0.05). As a result of preventive measures curtailing saw usage time in the VWF workers, the daily vibration exposure in group C was lower in 1995 than in 1990 (P = 0.02). In the retired workers, FSBP%10 degrees was positively related to the time since the cessation of work with chain saws (P < 0.01). The findings of this follow-up study indicate that a reduction in or cessation of exposure to vibration has a beneficial effect on finger-blanching symptoms and the cold response of digital vessels. The occurrence of new cases of VWF in subjects whose work experience was limited to AV chain saws argues for the maintenance of health surveillance in these workers.

Hand-arm vibration syndrome among travertine workers: a follow up study.

In a six year follow up study of the handarm vibration syndrome, 62 stoneworkers operating hand held vibrating tools in 10 travertine quarries and mills were first investigated in 1985 and then in 1991. The frequency weighted acceleration of vibration from the rock drills and stone hammers used by the travertine workers exceeded 20 m/s2, indicating a hazardous work activity according to the proposal of the EC directive for physical agents. A clinical examination and a cold provocation test were repeated with the same procedures as those adopted at the time of the first survey. The stoneworkers were divided into groups according to current work state: active stoneworkers who continued to use powered tools during the follow up (n = 21, median exposure time 22 years), and ex-stoneworkers with retirement vibration free intervals of three years (n = 22, median exposure time 27.5 years) and of six years (n = 19, median exposure time 20 years). In the group of active stoneworkers, a 38% onset a new cases of vibration-induced white finger (VWF) was found during the follow up (p < 0.01). Among the retired stoneworkers affected with VWF (n = 24), one recovered from VWF, one showed improvement, 20 remained stationary, and two deteriorated. The ex-stoneworkers experienced no significant change in sensorineural disturbances and a decrease in musculoskeletal symptoms of the upper limbs. At the cold provocation test, the currently active stoneworkers with VWF showed, on a group basis, a delayed finger rewarming time between the two examinations (p = 0.002). An abnormal response to cold provocation persisted in the fingers of the ex-stoneworkers with VWF, even in those reporting subjective improvement. These findings indicate a tendency towards the irreversibility of sensorineural and VWF symptoms in a group of ex-stoneworkers with prolonged exposure to high vibration levels in the past. The increased occurrence of VWF in the active stone workers after a few extra years of vibrating tool usage argues for an urgent implementation of preventive measures in the stone industry.

Assessment of the mechanical properties of peripheral arteries in chain saw operators using a photosensor.

In order to evaluate the severity of peripheral vascular disorders, and to detect changes in the digital arteries of workers who use chain saws, the mechanical properties of the digital arteries of 22 such workers were examined using a photosensor. The elastic properties and the nonlinearity of digital arteries were assessed through observation of the changes in the vascular volume ratio (V/Vo) against the volume (Vo) at mean blood pressure (Pm). A significant negative correlation was found between age and V/Vo at a transmural pressure of 30 mmHg (V30/Vo), which suggested that V30/Vo tended to decrease with aging. Although it was impossible to calculate V30/Vo for chain saw operators because of the vague changes in the volume pulse wave, this nonlinearity was more clearly observed through changes in the relative vascular volume (V/V40) along with a reduction in cuff pressure (Pc) to 40 mmHg below systolic blood pressure. A group of similarly aged healthy controls and three groups of workers with a different severity of vibration-induced white finger (VWF), i.e., no symptoms of VWF, mild VWF and severe VWF, were classified according to the changes in their V/V40 and the reduction in Pc. The results obtained in the present study suggest that the peripheral vascular disorders in workers using chain saws are due to the opening disturbance of the arteries with nonlinear changes in the peripheral artery, which is related to functional and organic abnormality of the arteries.

Hearing loss risk from exposure to shooting impulses in workers exposed to occupational noise.

The effect of shooting impulses on hearing was analysed in 150 professional forest workers exposed to noise from chain saws. The exposure to shooting impulses (Lesi) was designed to take into account the peak levels of shooting impulses, their number and use of hearing protectors. Hearing loss was dependent on Lesi even after allowing for the age of subjects and their exposure to chain saw noise. Hearing threshold levels were compared between pairwise matched groups with high and low Lesi. Proper matching was achieved for age, chain saw noise, salicylate consumption, blood pressure, cholesterol, smoking and vibration-induced white finger symptoms. The workers with high Lesi had 9 dB greater hearing loss at 4 kHz and 10 dB greater hearing loss at 8 kHz than those with low Lesi, the difference being significant at P < 0.05 level. In evaluation of noise-induced hearing loss the exposure to shooting impulses from different calibre weapons should be determined since they increase the extent of hearing loss. The present study describes the Lesi method which more accurately evaluates the harmful effects of shooting noise impulses on hearing.

Hand-arm vibration syndrome and its prevalence in the present status of private forestry enterprises in Japan.

Currently there are no limitations on age of employment on private forestries in Japan. Hence, it was hypothesized that in these kind of enterprises, elderly chain saw operators, or those with long-term exposure, might be at higher risk of developing hand-arm vibration syndrome (HAVS). We consequently investigated the prevalence of HAVS in 447 chain saw workers on private forestries in Gifu Prefecture, Japan, with particular reference to age and exposure period. Of this population, 43 (9.6%) had signs and symptoms of vibration-induced white finger (VWF), and among these workers the severity of finger blanching was significantly correlated (P less than 0.01) with the exposure period. Classification of all subjects by exposure period showed that workers with greater than or equal to 30 years' exposure had higher prevalences of VWF (20.9%) and numbness of the hands (25.4%) compared to other groups. Significant differences (P less than 0.01) were found between the functional capacities of workers with VWF and those of control subjects. We concluded that (a) the elderly chain saw operators and those with longer exposure should be moved to other jobs with a lower or no risk of exposure to vibration, and (b) the results of screening tests, even without cold water immersion (which we did not employ, in order to protect workers' hands), could be helpful for the identification of workers with VWF.

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Workers using vibrating tools may experience neurological and vascular symptoms in the fingers and hands. The effect of vibration exposure on bone and joint disorders in the hand, arm and shoulder is less clear. In a cross-sectional study, riveters and controls in an aircraft company were investigated for vibration exposure and health complaints. Vibration measurements showed that frequency-weighted acceleration levels for riveting hammers and bucking bars ranged from 5.5 to 12.3 m s -2. The calculated equivalent frequency-weighted acceleration for a period of 4 h was the questionnaire survey 101 riveters reported statistically significant more complaints of pain and stiffness in their hands and arms when compared with 76 controls with no, or little, exposure to vibration. After 10 years of exposure statistically significant age-adjusted odds ratios (P less than 0.05) were found for vibration-induced white finger (VWF) (1.9) and pain or stiffness of the wrist (3.2). Although they were not statistically significant (0.05 less than P less than 0.10) odds ratios appreciably greater than 1 were found for numbness in fingers (1.6) and pain or stiffness in the elbow (1.6) and the shoulder (1.5), and these complaints were strongly associated with duration of exposure to vibration. With logistic regression the probabilities for a riveter of having symptoms of VWF after 10 and 20 years of exposure was estimated to be P = 0.18 and P = 0.29, respectively, which can be compared with the prevalences predicted by the dose-response relationship for VWF in ISO 5349, which are 10 and 30%. The results of this study suggest that exposure to vibration from working with impact power tools can contribute to complaints of pain and stiffness in the hand, arm and shoulder, and especially in the wrist.

Transmission of Vibration from Tool Handle to Wrist and to Head

Transmission of vibration from the handle of the tool to the handarm system was investigated by measuring vibration in pairs from the source and from the wrist and head. The frequency response function was applied to describe the transmission properties. The measurements were taken at work places to evaluate the effect of different work-related factors on the transmission. Laboratory measurements were conducted to evaluate the effect of different grip forces and the use of protective gloves on the transmission. The field measurements comprised five different groups of workers whose exposure to vibration was evaluated and whose observed symptoms of vibration-induced white finger (VWF) was compared to the predicted ones based on the exposure data and on ISO 5349. The comparison of the prevalence data was in good agreement for the forest workers. The ISO method seemed to underestimate the genesis of VWF in workers who had to use high grip forces and for whom the vibration comprised high values of impulsiveness. The present results suggest that the frequency response function as independent of the input signal may thus describe factors important to the transmission of vibration.

Vasoconstrictor response to cold in forestry workers: a prospective study.

In a five year prospective study of the vasoconstrictor response to cold 37 forestry workers were investigated in 1978 and again in 1983. The subjects were classified into three groups: group A (n = 13): no subjective finger symptoms in 1978 and continued sawing until 1983; group B (n = 12): no symptoms in 1978 and stopped sawing before 1983; group C (n = 12): vibration induced white finger (VWF) in 1978. A cold provocation test measuring the finger systolic blood pressure with a cuff and strain gauge technique during combined body cooling and finger cooling to 30 degrees, 15 degrees, and 6 degrees C was applied to all subjects at both investigations. In 1978 all groups had an increased cold response when compared with that of 20 non-exposed controls (p less than 0.05), and the response was more exaggerated in group C than in groups A and B (p less than 0.01). From 1978 to 1983 the vasoconstrictor response increased in group A (p less than 0.05), was in group B (p greater than 0.10), and improved in group C (p less than 0.05). The changes in cold response in groups A and C were significantly larger than the within day variation of the method (p less than 0.01). The aggravation of group A indicates that a further five years use of anti-vibration chain saws induced an increased hyperreactivity in the vasoconstrictor mechanisms but led to subjective symptoms of VWF in only one subject. The improvement in group C was in accordance with the improvements of subjective finger symptoms and was associated with a previous shift from saws without vibration damping devices to anti-vibration saws and with cessation of work. The results of group C indicate that VWF may improve or subjectively disappear if exposure to vibration is reduced or stopped. The cold provocation test was more sensitive than the Taylor-Pelmear stage assessments (p<0.05). The test may be of guidance in evaluation preventive measures.

Finger thermometry in the assessment of subjects with vibration-induced white finger.

The measurement of finger skin temperature (FST) is one of the most commonly used methods for evaluating the response of the digital vessels to cold stimulation. In well-controlled experiments a significant correlation has been observed between FST and digital blood flow over a wide range of water temperatures. On the contrary, FST in air is considered an inadequate index of digital skin circulation since, at a given ambient temperature, FST depends not only on the rate of blood flow through the digit but also on environmental conditions. Despite these limitations, FST recording after a cooling procedure has been used in surveys of vibration-induced white finger (VWF), and a delayed finger rewarming time has been proposed as an indicator of digital vasospasm in workers with VWF. Finger skin thermometry can differentiate between VWF groups and healthy groups, but it is unsuitable for diagnosing Raynaud's phenomenon on an individual basis. The thermometric method has good specificity but its sensitivity is lower than that of plethysmographic techniques. FST after cold provocation may be considered a useful screening test in field studies, while more sensitive methods should be employed to confirm VWF symptoms in individuals objectively, especially for insurance compensation purposes.

Measures of vibrotactile sensitivity in persons exposed to hand-arm vibration.

A group of 57 persons occupationally exposed to hand-arm vibration was studied in an investigation of factors affecting their vibrotactile thresholds. The group contained 42 persons with symptoms of vibration-induced white finger (VWF). Measures of finger thresholds and temperatures were obtained from both hands. It was found that vibrotactile thresholds were higher in subjects reporting VWF. A laboratory investigation indicated that finger temperature had a great effect on the thresholds but that this effect only occurred outside the range of temperatures found in the study of occupationally exposed persons. Laboratory research showed that vibrotactile thresholds should be expected to depend upon vibration exposure immediately prior to the test. The vibration frequency and general configuration of the vibrotactile apparatus also influenced threshold. An awareness of these factors allows guidelines for their control to be suggested.

Chipping hammer vibration.

An investigation was carried out to determine the factors influencing the vibration of chipping hammers and to find ways of reducing the vibration at the operator's hand. It showed that substantially higher vibration levels are produced at the chisel of a chipping hammer than at its handle. Typical weighted values for the two areas were 24 and 8 m/s2, respectively. This finding agrees with medical observations showing that invariably the hand holding the chisel exhibits the more severe symptoms of vibration-induced white finger. A sleeve which fits onto the chisel was developed which can effect a reduction in vibration of up to 66%. A prototype hammer was developed incorporating an isolating material which reduced the weighted vibration value from 7 to 3 m/s2. Vibration isolating gloves were tested and resulted in an additional reduction in vibration of up to 63% when used with the chisel sleeve. A unique mounting device using rubber isolators was designed which protects the accelerometer from very intense high-frequency vibration but allows accurate measurement of chisel vibration in the frequency range of interest.

Exposure conditions and Raynaud's phenomenon among riveters in the aircraft industry.

Riveters in the aircraft industry work daily with such vibrating tools as riveting hammers, bucking bars, drills, and rivet shavers. The main contribution of the vibration exposure comes from the riveting tools. Three hundred and forty riveters working at the Aircraft Division of Saab-Scania were investigated in respect to vibration exposure and symptoms of Raynaud's phenomenon. The employment time of this group varied from 1 to 44 years. Within the group, 86 riveters showed symptoms of Raynaud's phenomenon. The latency until first sign of injury ranged from 0 to 27 years with a median of almost 11 years. Although the exposure time for the riveting hammer was 1 min and the total tool time was 40 min per day, more than 50% of the riveters had symptoms of vibration-induced white finger (VWF) after more than 10 years of work. The guidelines of the International Organization for Standardization (ISO/DIS 5349) suggest a lesser risk, and they should therefore be complemented with additional criteria to be valid for percussion tools.

Impulsiveness of vibration as an additional factor in the hazards associated with hand-arm vibration.

Impulsiveness is defined as the difference between peak and root-mean-square signals. As the difference varies in time, the cumulative distribution function has been used to describe the probability of achieving a certain value of impulsiveness. To make numerical comparison of different vibration signals possible, an impulse index has been selected from the cumulative distribution function. Symptoms of vibration-induced white finger were observed and compared to those expected on the basis of measurements taken according to guidelines of the International Organization for Standardization (ISO). Agreement was found for chain-saw vibration. In the case of pedestal grinding, the ISO draft underestimated the hazardous effects of vibration. Stone workers using pneumatic hammers were exposed to highly impulsive but asymmetrical vibration. The corresponding asymmetry was not, however, observed between the symptoms of the left and right hands, a finding which indicates that coupling between the tool and the hand is important for impulse vibration. The results suggest that the impulse character of vibration increases the risk of vibration-induced pathology. The analysis of high-impulse acceleration peaks obtained by the method presented in this study could provide additional data necessary to improve risk assessment.

Vibration syndrome among Finnish forest workers, a follow-up from 1972 to 1983.

A longitudinal survey on the prevalence of vibration syndrome among professional forest workers was conducted from 1972 (118 workers) to 1983 (206 workers). The prevalence of vibration-induced white finger (VWF) was 40% among the workers in 1972; it gradually declined to 5% in 1983. Three new workers developed VWF symptoms during the follow-up period. They had only used saws equipped with antivibration handles. The prevalence of VWF has decreased mainly due to the reduction of chain-saw vibration. The prevalence of paresthesias of the hands and arms declined from 78% in 1972 to 37% in 1976, and then increased to 51% in 1983. The recent increase was thought to be due to static muscle load and the ageing of the workers. No correlation was found between the severity of VWF and peripheral nerve symptoms. No significant changes in muscle fatigue occurred during the follow-up period; it was present in about 10-15% of the workers. The forest workers subjectively assessed musculoskeletal load and strain as being more harmful than the symptoms of vibration syndrome. The preventive measures aimed at reducing chain-saw vibration, implemented since 1970, have been beneficial and explain the decreased prevalence of VWF.