Tremor measurements in a 22-year cohort study of workers exposed to hand-held vibrating tools

Rita Bast-Pettersen,Lisa Aarhus,Gunilla Wastensson,Karl-Christian Nordby

doi:10.1007/s00420-020-01612-8

Abstract

ObjectivesThe objectives of this cohort study were to evaluate possible long-term effects of occupational exposure to hand-arm vibration (HAV) in terms of increased tremor. The aims were to evaluate whether exposure during follow-up, baseline hand-arm vibration syndrome (HAVS), baseline manual dexterity or current medical conditions or life-style habits might be associated with increased tremor. A further aim was to compare two different activation conditions: postural vs rest tremor.MethodsForty men (current age: 60.4 years) who had previously worked as manual workers in a specialized engineering and construction company enrolled in the study. Their hand functions had been examined in 1994. At the baseline examination, 27 had been diagnosed with HAVS, while 13 were not exposed. The follow-up examination in 2016–2017 comprised the CATSYS Tremor Pen® for measuring postural and rest tremor and the Grooved Pegboard Test for assessing manual dexterity. Blood samples were taken for assessing biomarkers that might have impact on tremor.ResultsNeither cumulative exposure to HAV during follow-up nor HAVS at baseline were associated with increased tremor. A test for manual dexterity at baseline was significantly associated with increased tremor (Tremor Intensity) at follow-up. Blood markers of current medical conditions and tobacco consumption were associated with increased tremor. Rest tremor frequency was higher than postural tremor frequency (p < 0.001).ConclusionsThe main findings of this 22-year cohort study were no indications of long-term effects on tremor related to HAV exposure and previous HAVS status. However, baseline manual dexterity was significantly associated with increased tremor at follow-up. Activation conditions (e.g., hand position) are important when testing tremor.

Highlights

The use of hand-held vibrating tools can lead to hand injuries in terms of hand-arm vibration syndrome (HAVS), which is composed of vascular, neurological and muscular components (Burström et al 2006; Heaver et al 2011; Ye et al 2015)
In a recent study of tremor among HAV-exposed workers, we found differences in several tremor parameters associated with the activation condition (Bast-Pettersen et al 2017)
We interviewed the workers about their work and leisure exposure to hand-held vibrating tools; smoking habits and the use of smokeless tobacco; medical conditions; medications; and neurological, vascular or muscular symptoms of HAVS

Summary

Introduction

The use of hand-held vibrating tools can lead to hand injuries in terms of hand-arm vibration syndrome (HAVS), which is composed of vascular, neurological and muscular components (Burström et al 2006; Heaver et al 2011; Ye et al 2015). HAVS is often diagnosed by clinical examination based on the Stockholm workshop scale (Gemne et al 1987; Lawson 2016; Aarhus et al 2018; Poole et al 2019). A recent study by Vihlborg et al (2017) reported that 21% of a group of examined workers with hand-arm vibration (HAV) exposure had vibration injuries. The sensorineural component of HAVS is usually evaluated by scoring systems such as the Stockholm sensorineural system (Brammer et al 1987), by vibrometry and by tests for manual dexterity, for. It has been proposed that other forms of evaluation systems can sometimes be more appropriate (Griffin 2008)

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