Department of Biological and Clinical Psychology, Friedrich-Schiller-University of Jena, Jena D-07743, Germany Department of Palliative Care, University of Bonn, Bonn, Germany.
Pain. 2012 Aug;153(8):1687-1694. doi: 10.1016/j.pain.2012.04.029. Epub 2012 May 31.
Patients suffering from postherpetic neuralgia often complain about hypo- or hypersensation in the affected dermatome. The loss of thermal sensitivity has been demonstrated by quantitative sensory testing as being associated with small-fiber (Aδ- and C-fiber) deafferentation. We aimed to compare laser stimulation (radiant heat) to thermode stimulation (contact heat) with regard to their sensitivity and specificity to detect thermal sensory deficits related to small-fiber dysfunction in postherpetic neuralgia. We contrasted detection rate of laser stimuli with 5 thermal parameters (thresholds of cold/warm detection, cold/heat pain, and sensory limen) of quantitative sensory testing. Sixteen patients diagnosed with unilateral postherpetic neuralgia and 16 age- and gender-matched healthy control subjects were tested. Quantitative sensory testing and laser stimulation of tiny skin areas were performed in the neuralgia-affected skin and in the contralateral homologue of the neuralgia-free body side. Across the 5 thermal parameters of thermode stimulation, only one parameter (warm detection threshold) revealed sensory abnormalities (thermal hypoesthesia to warm stimuli) in the neuralgia-affected skin area of patients but not in the contralateral area, as compared to the control group. In contrast, patients perceived significantly less laser stimuli both in the affected skin and in the contralateral skin compared to controls. Overall, laser stimulation proved more sensitive and specific in detecting thermal sensory abnormalities in the neuralgia-affected skin, as well as in the control skin, than any single thermal parameter of thermode stimulation. Thus, laser stimulation of tiny skin areas might be a useful diagnostic tool for small-fiber dysfunction.
患有带状疱疹后神经痛的患者常主诉受累皮区出现感觉迟钝或过敏。定量感觉测试显示，热敏觉丧失与小纤维（Aδ 和 C 纤维）去传入有关。我们旨在比较激光刺激（辐射热）与热刺激（接触热）在探测与带状疱疹后神经痛中小纤维功能障碍相关的热感觉缺失方面的敏感性和特异性。我们对比了激光刺激的检出率与定量感觉测试的 5 个热参数（冷/温觉、冷/热痛觉和感觉阈值）。16 例单侧带状疱疹后神经痛患者和 16 例年龄和性别匹配的健康对照者接受了测试。在神经痛受累皮肤和神经痛无皮肤的对侧同部位进行定量感觉测试和微小皮肤区域的激光刺激。在热刺激的 5 个热参数中，只有一个参数（温觉阈值）在患者的神经痛受累皮肤区域显示感觉异常（对温刺激的热感觉减退），而在对侧区域则与对照组无差异。相比之下，患者在受累皮肤和对侧皮肤感知到的激光刺激明显少于对照组。总体而言，与热刺激的任何单一热参数相比，激光刺激在探测神经痛受累皮肤以及对照皮肤的热感觉异常方面更敏感和特异。因此，微小皮肤区域的激光刺激可能是探测小纤维功能障碍的有用诊断工具。
