Test-retest reliability of neurophysiological tests of hand-arm vibration syndrome in vibration exposed workers and unexposed referents.

Lars Gerhardsson,Lennart Gillström,Mats Hagberg

doi:10.1186/s12995-014-0038-1

Abstract

BackgroundExposure to hand-held vibrating tools may cause the hand-arm vibration syndrome (HAVS). The aim was to study the test-retest reliability of hand and muscle strength tests, and tests for the determination of thermal and vibration perception thresholds, which are used when investigating signs of neuropathy in vibration exposed workers.MethodsIn this study, 47 vibration exposed workers who had been investigated at the department of Occupational and Environmental Medicine in Gothenburg were compared with a randomized sample of 18 unexposed subjects from the general population of the city of Gothenburg. All participants passed a structured interview, answered several questionnaires and had a physical examination including hand and finger muscle strength tests, determination of vibrotactile (VPT) and thermal perception thresholds (TPT). Two weeks later, 23 workers and referents, selected in a randomized manner, were called back for the same test-procedures for the evaluation of test-retest reliability.ResultsThe test-retest reliability after a two week interval expressed as limits of agreement (LOA; Bland-Altman), intra-class correlation coefficients (ICC) and Pearson correlation coefficients was excellent for tests with the Baseline hand grip, Pinch-grip and 3-Chuck grip among the exposed workers and referents (N = 23: percentage of differences within LOA 91 – 100%; ICC-values ≥0.93; Pearson r ≥0.93). The test-retest reliability was also excellent (percentage of differences within LOA 96–100 %) for the determination of vibration perception thresholds in digits 2 and 5 bilaterally as well as for temperature perception thresholds in digits 2 and 5, bilaterally (percentage of differences within LOA 91 – 96%). For ICC and Pearson r the results for vibration perception thresholds were good for digit 2, left hand and for digit 5, bilaterally (ICC ≥ 0.84; r ≥0.85), and lower (ICC = 0.59; r = 0.59) for digit 2, right hand. For the latter two indices the test-retest reliability for the determination of temperature thresholds was lower and showed more varying results.ConclusionThe strong test-retest reliability for hand and muscle strength tests as well as for the determination of VPTs makes these procedures useful for diagnostic purposes and follow-up studies in vibration exposed workers.

Highlights

Exposure to hand-held vibrating tools may cause the hand-arm vibration syndrome (HAVS)
The test-retest reliability expressed as percentage of differences within limits of agreement (LOA), intra-class correlation coefficients (ICC) and Pearson correlation coefficients (r) after a 2-week interval was excellent in the study group (N = 23) for the hand and finger muscle strength tests (Baseline hand grip, Pinch-grip and 3-Chuck grip), percentage of differences within LOA 91%-100%; ICCvalues ≥0.93; r ≥0.93 (Tables 1 and 2)
The main findings in this study are excellent to very good test-retest reliabilities for tests with Baseline hand grip, Pinch grip and 3-Chuck grip as well as for the determination of vibration perception thresholds with vibrometry

Summary

Introduction

Exposure to hand-held vibrating tools may cause the hand-arm vibration syndrome (HAVS). The aim was to study the test-retest reliability of hand and muscle strength tests, and tests for the determination of thermal and vibration perception thresholds, which are used when investigating signs of neuropathy in vibration exposed workers. Vibration exposure may cause several symptoms and signs, e.g. vascular changes, distal neuropathy and musculoskeletal disturbances, depicted as the Hand-Arm Vibration Syndrome (HAVS; [1]). Low-frequency impact vibration can be transmitted to the upper arm and cause symptoms in the elbow and shoulder, while high-frequency impact vibration can give more peripheral symptoms in e.g. the wrist and hand [2]. Vibration exposure can cause injuries to peripheral nerves, such as segmental demyelination, axonal atrophy, degeneration and primary disorders of cell bodies [4]. The tests vary in complexity and they are dependent on many factors, e.g. the time for examination and the costs

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