Bovenzi M, Apostoli P, Alessandro G, Vanoni O
Institute of Occupational Medicine, University of Trieste, Italy.
Occup Environ Med. 1997 Aug;54(8):577-87. doi: 10.1136/oem.54.8.577.
To investigate the changes over a workshift in fingertip tactile perception thresholds in users of impact wrenches exposed to intermittent hand transmitted vibration. A further aim was to assess the relation between acute changes in tactile sensation, sensorineural disorders, and vibration dose.
The study populations consisted of 30 workers exposed to vibration (16 men and 14 women) and 25 control manual workers (10 men and 15 women). Sensorineural disorders in the fingers and hands were graded according to the staging system of the Stockholm workshop scale. Tactile function was tested by measuring aesthesiometric thresholds (two point discrimination and depth sense perception) and vibrotactile perception thresholds at 16, 31.5, and 125 Hz before and after a workshift. Temporary threshold shift was then calculated as the difference between threshold measures before and after the shift. The measurement and assessment of exposure to vibration were made according to the international standard ISO 5349. The vibration dose accumulated over a workshift (m2s-4h) was estimated for each user of impact wrenches. Daily exposure to vibration was also expressed in terms of eight hour energy equivalent frequency weighted acceleration ((ahw)eq(8) in ms-2 rms).
After adjustment for age and alcohol consumption, vibrotactile perception thresholds before exposure were greater in the workers exposed to vibration than in the controls. No differences in aesthesiometric thresholds before the shift were found between the study groups. Sensorineural disorders were mild in the workers exposed to vibration and minor neurological abnormalities were detected at the physical examination. Owing to the intermittent use of impact wrenches, the estimated mean (ahw)eq(8) for the subjects exposed to vibration was low (1.3 ms-2 rms). A significant temporary threshold shift in vibration perception at all test frequencies was found in the workers exposed to vibration but not in the controls. A significant increase in depth sense perception thresholds was found in the men exposed to vibration. The temporary threshold shift in vibration perception at 125 Hz, and to a lesser extent at 16 and 31.5 Hz, was associated with the severity of sensorineural disorders. In the workers exposed to vibration the temporary threshold shift in vibration sense at all test frequencies was positively related to the estimated dose of vibration received over a workshift. No significant relation was found between aesthesiometric threshold changes and vibration dose.
Intermittent exposure to hand transmitted vibration over a workshift can cause a deterioration of tactile perception in the fingers of users of impact wrenches. Acute tactile dysfunction was related to both the estimated dose of vibration and the severity of sensorineural symptoms. The temporary threshold shift in vibration perception suggested that fast adapting skin mechanoreceptors such as Pacinian and Meissner corpuscles were mainly involved in the acute sensory impairment to the fingertips of the workers exposed to vibration. Changes in tactile perception can occur in workers with daily exposure to vibration that is considered to be associated with a minimal risk of adverse health effects induced by vibration.
研究使用冲击扳手、暴露于间歇性手部传递振动的工人在一个工作班次中指尖触觉感知阈值的变化。另一个目的是评估触觉感觉的急性变化、感觉神经障碍与振动剂量之间的关系。
研究人群包括30名暴露于振动的工人（16名男性和14名女性）和25名对照体力劳动者（10名男性和15名女性）。根据斯德哥尔摩研讨会量表的分期系统对手指和手部的感觉神经障碍进行分级。在工作班次前后，通过测量感觉阈值（两点辨别和深度感觉）以及16、31.5和125Hz的振动触觉感知阈值来测试触觉功能。然后将暂时阈值偏移计算为偏移前后阈值测量值之间的差异。根据国际标准ISO 5349进行振动暴露的测量和评估。为每个冲击扳手使用者估算一个工作班次中累积的振动剂量（m²s⁻⁴h）。每日振动暴露也用八小时能量等效频率加权加速度（（ahw）eq(8)，单位为ms⁻²rms）表示。
在对年龄和酒精摄入量进行调整后，暴露于振动的工人暴露前的振动触觉感知阈值高于对照组。研究组之间在偏移前的感觉阈值方面未发现差异。暴露于振动的工人感觉神经障碍较轻，体格检查时检测到轻微的神经异常。由于冲击扳手的间歇性使用，暴露于振动的受试者的估计平均（ahw）eq(8)较低（1.3ms⁻²rms）。在暴露于振动的工人中发现所有测试频率下的振动感知均有显著的暂时阈值偏移，而对照组未出现。在暴露于振动的男性中发现深度感觉阈值有显著增加。125Hz时的振动感知暂时阈值偏移，以及在较小程度上16和31.5Hz时的偏移，与感觉神经障碍的严重程度相关。在暴露于振动的工人中，所有测试频率下振动感觉的暂时阈值偏移与一个工作班次中接收的估计振动剂量呈正相关。在感觉阈值变化与振动剂量之间未发现显著关系。
在一个工作班次中间歇性暴露于手部传递的振动会导致冲击扳手使用者手指的触觉感知恶化。急性触觉功能障碍与估计的振动剂量和感觉神经症状的严重程度均有关。振动感知的暂时阈值偏移表明，快速适应的皮肤机械感受器如环层小体和梅克尔小体主要参与了暴露于振动的工人指尖的急性感觉损伤。在每日暴露于被认为与振动引起的不良健康影响最小风险相关的振动的工人中，可能会出现触觉感知的变化。
