Measurement, evaluation, and assessment of peripheral neurological disorders caused by hand-transmitted vibration

Abstract

Regular exposure to hand-transmitted vibration can result in symptoms and signs of peripheral vascular, neurological and other disorders collectively known as the handarm vibration syndrome. The measurement of the effects of hand-transmitted vibration involves converting the evidence of disorder (symptoms and signs) into information that can be stored. Evaluation requires the use of scales on which to indicate the severity of the various symptoms and signs. Assessment involves a judgement of severity relative to a criterion, usually for a specific purpose (e.g. to decide on removal from work or compensation). The measurement and evaluation of symptoms and signs is necessary when monitoring patient health and when performing epidemiological studies for research. The assessment of the severity of the hand-arm vibration syndrome is currently performed with staging systems, but the criteria are not clear and not related to defined methods for measuring or evaluating the symptoms and signs. Recognising that similar symptoms can occur without injury from occupational exposures to hand-transmitted vibration, this paper attempts to define significant peripheral neurological symptoms caused by hand-transmitted vibration (i.e. 'unusual symptoms') and how these symptoms and related signs may be measured. Scales for evaluating the symptoms (e.g. their extent) and the related signs (e.g. their probability relative to the probability of the sign being present in persons not exposed to vibration) are defined. A method of relating unusual symptoms to both the signs of disorder and the pattern of vibration exposure is illustrated. Assessments of severity will vary according to the reasons for assessing the health effects of vibration, and will depend on local practice and convenience, but a way of combining evaluations of symptoms and signs is demonstrated in a staging system. Although inherently complex, the methods may assist the collection of data required to improve understanding of the effects of hand-transmitted vibration and also support a more complete reporting of the condition in those adversely affected by hand-transmitted vibration.

Relationships of neurosensory disorders and reduced work ability to alternative frequency weightings of hand-transmitted vibration

“…The models with the smallest QIC values were also chosen as the best-fitting models for the relation between outcomes and vibration exposure. To aid comparison, a ΔQIC was calculated as the difference between the QIC value for a specific exposure model and the model including A (8) calculated with frequency weighting W h (ie, the ISO weighting method). By analogy, with the strength of evi- …”

“…Case definition did not include subjects who reported temporary presence of tingling or numbness occurring while or after working with vibratory tools, during or following episodes of VWF or exposures to cold environment (8). The diagnosis of VWF was based on the findings of the medical interview assisted by color charts according to the criteria established by the Stockholm Workshop 1994 (5).…”

Study of the biodynamic response of the foot to vibration exposure

“…Therefore, changes in transmissibility reported in this study may not strictly be due to changes in frequency, since vibration exposure magnitude also increased when exposure frequency increased. Furthermore, several researchers have reported transmissibility increases with increasing magnitude [9,36,37]. Second, although participants' foot placement was controlled and all were given the same instruction with regard to how to stand, it could not be confirmed that all participants' maintained the same posture throughout the 45-second FTV exposure period.…”

“…Raynaud's phenomenon of the feet has been examined mostly in conjunction with HAVS [7][8][9][10][11][12][13]. Given the similarities between the anatomy of the hands and feet it is not unreasonable to speculate that their resonant frequencies would be in the same range.…”

A prospective cohort study investigating an exposure–response relationship among vibration-exposed male workers with numbness of the hands

“…The concept of numbness in the hand can be defined as an absence or loss of tactile sensation and may be associated with other symptoms like prickling or burning sensations, even though this may not be the only relevant definition. Patients can easily interpret symptoms differently or may have another definition for the symptom, which may confuse the picture of how common the HAVS is (23).…”