The relationship between clinical and standardized tests for hand-arm vibration syndrome

Vocational rehabilitative decisions after symptoms and findings consistent with hand-arm vibration syndrome in the Swedish surveillance system - a mixed-method design

BACKGROUND

EU workers exposed to hand-arm vibration should be offered health surveillance to detect early symptoms, and findings, of Hand-Arm Vibration Syndrome (HAVS). To execute the mandatory vocational rehabilitation, the employer needs to be aware of injuries found in the medical check-up. We aimed to analyse: 1) How physicians graded the neurosensory component of HAVS on the Stockholm Workshop Scale (SWS), compared to semi-objective findings. 2) What vocational rehabilitative decisions (VRD) were taken by physicians after examinations. 3) Whether the VRDs differed in relation to the SWS-grading.

METHODS

Data came from 660 medical records - all examinations performed during twelve consecutive months in one large Swedish occupational healthcare company. 572 individuals had data on the SWS from the physician. For the qualitative analysis, we used the inductive-iterative immersion-crystallization method.

RESULTS

60% of the examined workers had symptoms and 32% had semi-objective findings consistent with HAVS. The physicians' SWS gradings were underestimated in 59% of the cases with semi-objective findings. The VRDs were classified, relative to communication with the employer, as: "Adequate" (57%), when no injury was present, communication had already taken place, was planned, or was no longer needed in the absence of further exposure, "Semi-adequate" (18%), if no plan for communication was yet established or only communicated through a document with a shorter time until next check-up, and "Inadequate"(25%), when patients refused (20%), or physicians failed to communicate with the employer, despite findings (80%). Underestimated SWS-gradings of HAVS were significantly associated with more "Inadequate" VRDs in the group with semi-objective findings.

CONCLUSIONS

Occupational physicians underestimate the number of individuals with SWS 2-3 compared with semi-objective findings and regularly fail to communicate to the employer despite findings of HAVS. The underestimation of SWS-grading, followed by inadequate VRDs, excludes many workers from the employer's mandatory protective measures which may lead to aggravation of an untreatable injury in the affected individual and development of HAVS in their similarly exposed colleagues.

Vibrotactile sensitivity testing for occupational and disease-induce peripheral neuropathies

The International Standard Organization (ISO) standard 13091-1 describes methods and procedures for performing the vibrotactile perception threshold (VPT) testing to diagnose changes in tactile sensory function associated with occupational exposures. However, the VPT test also has been used in the diagnosis of peripheral neuropathies associated with a number of disorders. This review examines the VPT test, variations in procedures that have been used, as well as disorders and diseases in which this test has been reliable for the detection of sensory changes. Mechanisms potentially underlying the changes in VPTs are also discussed along with procedural and subject/patient factors that may affect the interpretation of test results. Based upon the review of the literature, there are also suggestions for where additional research might improve the administration of this test, depending upon the subject/patient population and interpretation of data.

Sensory perception testing by monofilaments in the digits of controls and workers with HAVS

Objective

To determine if heavy manual work affects sensory perception in the digits and whether Semmes–Weinstein monofilaments (SWM) can be used as a screening tool to detect sensory neuropathy in the digits of workers exposed to hand-transmitted vibration (HTV).

Methods

A cross-sectional study of office workers, heavy manual workers not exposed to HTV and workers with hand-arm vibration syndrome (HAVS). Sensory perception was measured in the digits by SWM using a forced-choice method to determine variability by sex, age, hand and digit. Frequency distributions were used to determine limit values and linear weighted kappa for intra-digit variability. Poisson regression was used to explore the relationship between sensory perception by SWM and abnormalities of thermal and vibration perception in the hands of workers with HAVS.

Results

The sensory perception threshold of office workers did not vary by hand or digit. It was significantly lower in women < 30 than women aged ≥ 30 years. The 95th percentile for heavy manual workers was 1.00 (95% CI 0.60–1.00) and significantly higher than for office workers at 0.16 (95% CI 0.16–0.16). Heavy manual workers > 50 years had the highest threshold at 1.40 (95% CI 1.00–2.00). Weighted kappa for reliability was 0.63 (95% CI 0.53–0.70). A mean SWM threshold of ≥ 1.0 gram-force had a 79% sensitivity and 64% specificity for detecting abnormalities of thermal and vibration perception in the ipsilateral index and little fingers of workers with HAVS.

Conclusions

SWM are a useful screening tool for detecting sensory loss in the digits of workers exposed to HTV.

International consensus criteria for diagnosing and staging hand-arm vibration syndrome

PURPOSE

In the 30 years since the Stockholm Workshop Scale (SWS) was published, the scientific literature on hand-arm vibration syndrome (HAVS) has grown and experience has been gained in its practical application. This research was undertaken to develop an up-to-date evidence-based classification for HAVS by seeking consensus between experts in the field.

METHODS

Seven occupational physicians who are clinically active and have had work published on HAVS in the last 10 years were asked to independently take part in a three-round iterative Delphi process. Consensus was taken when 5/7 (72%) agreed with a particular statement. Experts were asked to provide evidence from the literature or data from their own research to support their views.

RESULTS

Consensus was achieved for most of the questions that were used to develop an updated staging system for HAVS. The vascular and neurological components from the SWS are retained, but ambiguous descriptors and tests without adequately developed methodology such as tactile discrimination, or discriminating power such as grip strength, are not included in the new staging system. A blanching score taken from photographs of the hands during vasospastic episodes is recommended in place of self-recall and frequency of attacks to stage vascular HAVS. Methods with the best evidence base are described for assessing sensory perception and dexterity.

CONCLUSIONS

A new classification has been developed with three stages for the clinical classification of vascular and neurological HAVS based on international consensus. We recommend it replaces the SWS for clinical and research purposes.

Health effects associated with occupational exposure to hand-arm or whole body vibration

Workers in a number of different occupational sectors are exposed to workplace vibration on a daily basis. This exposure may arise through the use of powered-hand tools or hand-transmitted vibration (HTV). Workers might also be exposed to whole body vibration (WBV) by driving delivery vehicles, earth moving equipment, or through use of tools that generate vibration at low dominant frequencies and high amplitudes, such as jackhammers. Occupational exposure to vibration has been associated with an increased risk of musculoskeletal pain in the back, neck, hands, shoulders, and hips. Occupational exposure may also contribute to the development of peripheral and cardiovascular disorders and gastrointestinal problems. In addition, there are more recent data suggesting that occupational exposure to vibration may enhance the risk of developing certain cancers. The aim of this review is to provide an assessment of the occupations where exposure to vibration is most prevalent, and a description of the adverse health effects associated with occupational exposure to vibration. This review will examine (1) various experimental methods used to measure and describe the characteristics of vibration generated by various tools and vehicles, (2) the etiology of vibration-induced disorders, and (3) how these data were employed to assess and improve intervention strategies and equipment that reduces the transmission of vibration to the body. Finally, there is a discussion of the research gaps that need to be investigated to further reduction in the incidence of vibration-induced illnesses and injuries.

Assessment of thermotactile and vibrotactile thresholds for detecting sensorineural components of the hand-arm vibration syndrome (HAVS)

BACKGROUND

Thermotactile thresholds and vibrotactile thresholds are measured to assist the diagnosis of the sensorineural component of the hand-arm vibration syndrome (HAVS).

OBJECTIVES

This study investigates whether thermotactile and vibrotactile thresholds distinguish between fingers with and without numbness and tingling.

METHODS

In 60 males reporting symptoms of the hand-arm vibration syndrome, thermotactile thresholds for detecting hot and cold temperatures and vibrotactile thresholds at 31.5 and 125 Hz were measured on the index and little fingers of both hands.

RESULTS

In fingers reported to suffer numbness or tingling, hot thresholds increased, cold thresholds decreased, and vibrotactile thresholds at both 31.5 and 125 Hz increased. With sensorineural symptoms on all three phalanges (i.e. numbness or tingling scores of 6), both thermotactile thresholds and both vibrotactile thresholds had sensitivities greater than 80% and specificities around 90%, with areas under the receiver operating characteristic curves around 0.9. There were correlations between all four thresholds, but cold thresholds had greater sensitivity and greater specificity on fingers with numbness or tingling on only the distal phalanx (i.e. numbness or tingling scores of 1) suggesting cold thresholds provide better indications of early sensorineural disorder.

CONCLUSIONS

Thermotactile thresholds and vibrotactile thresholds can provide useful indications of sensorineural function in patients reporting symptoms of the sensorineural component of HAVS.