BACKGROUND: Dynamic mechanical allodynia is traditionally induced by manual brushing of the skin. Brushing force and speed have been shown to influence the intensity of brush-evoked pain. There are still limited data available with respect to the optimal stroke number, length, force, angle and speed. Therefore, an automated brushing device (ABD) was developed, for which brushing angle and speed could be controlled to enable quantitative assessment of dynamic mechanical allodynia.OBJECTIVES: To compare the ABD with manual brushing using capsaicin-induced allodynia, and to investigate the role of stroke angle and speed on pain intensity.METHODS: Experimental dynamic mechanical allodynia was induced by an intradermal injection of capsaicin (100 μg) into the volar forearm of 12 healthy, male volunteers. Dynamic mechanical allodynia was rated on a 10 cm visual analogue scale (VAS) after each set of strokes at angles of 30°, 60° and 90° with speeds of 17 mm/s, 21 mm/s and 25 mm/s for each angle. A two-way ANOVA with repeated measures was performed to assess the influence of brushing parameters. To evaluate test-retest reliability, Bland-Altman 95% limits of agreement, including a coefficient of repeatability and an intraclass correlation coefficient (ICC), were determined.RESULTS: The angle and speed exhibited a significant impact on pain intensity (P<0.001 and P<0.015, respectively). Post hoc analysis showed that the highest pain intensity was recorded with an angle of 30° regardless of brushing speed. The ABD demonstrated superior test-retest reliability (coefficient of repeatability = 1.9 VAS; ICC=0.91) compared with manual brushing (coefficient of repeatability = 2.8 VAS; ICC=0.80; P<0.05). The most reliable combination of parameters (coefficient of repeatability = 1.3 VAS; ICC=0.97) was an angle of 60° and a speed of 21 mm/s.CONCLUSIONS: A controlled, automatic brushing method can be used for quantitative investigations of allodynic reactions, and is more reliable for quantitative assessment of dynamic mechanical allodynia compared with traditional manual brushing.

中文翻译：

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使用新型全自动刷牙装置评估辣椒素引起的动态机械性异常性疼痛的疼痛反应

背景：动态机械性异常性疼痛传统上是通过手动刷皮肤引起的。已显示刷牙力和速度会影响刷牙引起的疼痛的强度。关于最佳行程数，长度，力，角度和速度，仍然只有有限的数据可用。因此，开发了一种自动刷牙装置（ABD），该装置可控制刷牙角度和速度，以定量评估动态机械异常性疼痛。目的：比较ABD和使用辣椒素诱导的异常性疼痛进行手动刷牙的比较，并研究其作用方法：实验性动态机械性异常性疼痛是通过向12名健康男性志愿者的掌前臂皮内注射辣椒素（100μg）诱导的。在每组冲程后分别以30°，60°和90°的角度以10毫米视觉模拟量表（VAS）对动态机械性异常性疼痛进行评级，速度分别为17 mm / s，21 mm / s和25 mm / s角度。进行了两次重复测量的方差分析，以评估刷牙参数的影响。为了评估重测信度，确定了Bland-Altman 95％的一致性极限，包括重复性系数和组内相关系数（ICC）。结果：角度和速度对疼痛强度有显着影响（P <0.001和P <0.015）。事后分析表明，无论刷牙速度如何，以30°角记录的最高疼痛强度。ABD表现出卓越的重测可靠性（可重复性系数= 1.9 VAS； ICC = 0。91）与手动刷牙相比（重复性系数= 2.8 VAS; ICC = 0.80; P <0.05）。参数的最可靠组合（可重复性系数= 1.3 VAS; ICC = 0.97）为60°角和21 mm / s的速度。结论：可控的自动刷牙方法可用于异常性疼痛反应的定量研究与传统的手动刷牙相比，对于动态力学异常性疼痛的定量评估更加可靠。