J Orthop Sports Phys Ther. 2018 Oct;48(10):767-774. doi: 10.2519/jospt.2018.8230. Epub 2018 Jun 22.
Small-nerve fiber, or small-fiber, degeneration commonly occurs in patients with peripheral neuropathies, resulting in a deterioration of nerve function. Currently, the gold standard to identify small-fiber degeneration is through skin biopsy. Simple clinical tests aim to identify small-fiber degeneration, but their validity remains unknown.
To examine the validity of clinical tests to assess small-nerve fiber degeneration, using carpal tunnel syndrome as a model neuropathy.
One hundred seven participants (22 healthy, 85 with carpal tunnel syndrome) in this prospective, cross-sectional diagnostic accuracy study underwent pinprick testing of the index finger and were assessed for cold detection threshold and warm detection threshold using quantitative sensory testing. In a subgroup of patients with carpal tunnel syndrome (n = 51), cold and warm sensations were also tested, using coins at room and body temperature, respectively. The validity of these clinical tests was established against intra-epidermal nerve fiber density measured in skin biopsies from the index finger.
Optimal validity occurred with clusters of tests. Specifically, normal warm or cold sensation is highly sensitive to rule out small-fiber degeneration (sensitivity, 0.98; 95% confidence interval [CI]: 0.85, 0.99), but has a low specificity (0.20; 95% CI: 0.03, 0.52). By contrast, a reduction in pinprick is highly specific (0.88; 95% CI: 0.72, 0.95), and so can be used to rule in small-fiber degeneration. For quantitative sensory testing, the highest specificity (0.83) occurs for warm detection threshold and the highest sensitivity (0.84; 95% CI: 0.72, 0.91) for cold detection threshold or warm detection threshold.
Pinprick testing, followed by warm and cold tests if pinprick is normal, is a valid and cost-effective method to detect small-fiber degeneration. For quantitative sensory testing, warm detection threshold is useful for ruling in small-fiber degeneration. To rule out small-fiber degeneration, both cold detection threshold and warm detection threshold must be negative.
Diagnosis, level 2. J Orthop Sports Phys Ther 2018;48(10):767-774. Epub 22 Jun 2018. doi:10.2519/jospt.2018.8230.
小纤维，或小纤维，变性通常发生在周围神经病变患者中，导致神经功能恶化。目前，识别小纤维变性的金标准是通过皮肤活检。简单的临床测试旨在识别小纤维变性，但它们的有效性仍不清楚。
以腕管综合征为模型神经病，研究评估小神经纤维变性的临床测试的有效性。
在这项前瞻性、横断面诊断准确性研究中，107 名参与者（22 名健康，85 名腕管综合征）接受了食指刺痛测试，并使用定量感觉测试评估冷觉阈值和温觉阈值。在腕管综合征患者亚组（n=51）中，还使用硬币分别测试室温下和体温下的冷觉和温觉。这些临床测试的有效性是根据食指皮肤活检中的表皮内神经纤维密度来确定的。
最佳的有效性出现在测试集群中。具体来说，正常的温觉或冷觉对排除小纤维变性具有高度敏感性（敏感性，0.98；95%置信区间[CI]：0.85，0.99），但特异性低（0.20；95%CI：0.03，0.52）。相比之下，刺痛的减少具有高度特异性（0.88；95%CI：0.72，0.95），因此可以用于推断小纤维变性。对于定量感觉测试，温觉检测阈值的特异性最高（0.83），冷觉检测阈值和温觉检测阈值的敏感性最高（0.84；95%CI：0.72，0.91）。
刺痛测试，然后是正常刺痛的温觉和冷觉测试，是一种有效且具有成本效益的方法，可以检测小纤维变性。对于定量感觉测试，温觉检测阈值对推断小纤维变性有用。要排除小纤维变性，必须同时出现冷觉检测阈值和温觉检测阈值均为阴性。
诊断，2 级。J Orthop Sports Phys Ther 2018;48(10):767-774。2018 年 6 月 22 日在线发表。doi:10.2519/jospt.2018.8230.
