Sural/Radial Amplitude Ratio: A Useful Tool to Diagnose Non-Length-Dependent Neuropathy.

IF 3.1 3区医学 Q2 CLINICAL NEUROLOGY

Muscle & Nerve Pub Date : 2025-10-09 DOI:10.1002/mus.70046

Antoine Pegat, Antoine Gavoille, Florent Cluse, Martin Moussy, Philippe Petiot, Jean-Philippe Camdessanché, Françoise Bouhour

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引用次数: 0

Abstract

Introduction/aims: Patients with non-length-dependent neuropathy (NLDN) exhibit reduced sensory nerve action potential (SNAP) amplitudes in both lower and upper limbs. This study aimed to determine a threshold for the sural/radial amplitude ratio (SRAR) suggestive of NLDN.

Methods: This retrospective case-control study involved 60 patients with definite NLDN (sensory neuronopathy [SNN] or chronic inflammatory demyelinating polyradiculoneuropathy [CIDP]) and 30 patients with length-dependent neuropathy (LDN). The diagnostic performance of SRAR was evaluated using the area under the curve (AUC) of the modeled receiver operating characteristic (ROC) curve. The presence of a length-dependent electrodiagnostic (EDX) pattern, defined as a sural SNAP amplitude lower than the radial one, was evaluated in each group.

Results: SRAR could be calculated in 90/164 (54.9%) of patients screened. Among patients with NLDN, the median SRAR was 0.74 (IQR 0.50-1.00) compared to 0.17 (IQR 0.12-0.23) in patients with LDN. The ROC curve analysis for NLDN versus LDN yielded an AUC of 0.94 (95% CI, 0.883-0.979). The SRAR threshold of 0.33 provided a sensitivity of 84.4% (95% CI, 77.8%-90.9%), specificity of 86.9% (95% CI, 79.7%-94%). The length-dependent EDX pattern was observed in 100% (30/30) of LDN patients and 63% (38/60) of NLDN patients. Among these 38 patients with NLDN, SRAR exceeded 0.33 in 78.9% (30/38).

Discussion: SRAR appears to be useful in the electrophysiological evaluation of neuropathies. In addition to usual diagnostic criteria, an SRAR > 0.33 may strongly suggest NLDN such as SNN or CIDP.

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腓肠/桡动脉振幅比：诊断非长度依赖性神经病变的有用工具。

简介/目的：非长度依赖性神经病（NLDN）患者表现为下肢和上肢感觉神经动作电位（SNAP）振幅降低。本研究旨在确定提示NLDN的桡骨/桡骨振幅比（SRAR）的阈值。方法：本回顾性病例对照研究纳入60例明确的NLDN（感觉神经病变[SNN]或慢性炎性脱髓鞘性多根神经病变[CIDP]）患者和30例长度依赖性神经病变（LDN）患者。采用建模的受试者工作特征（ROC）曲线下面积（AUC）评价SRAR的诊断性能。在每组中评估长度依赖性电诊断（EDX）模式的存在，定义为桡骨SNAP振幅低于桡骨SNAP振幅。结果：90/164（54.9%）的筛查患者可计算出SRAR。NLDN患者的中位SRAR为0.74 (IQR 0.50-1.00)，而LDN患者的中位SRAR为0.17 （IQR 0.12-0.23）。NLDN与LDN的ROC曲线分析显示AUC为0.94 （95% CI, 0.883-0.979）。SRAR阈值为0.33，敏感性为84.4% (95% CI, 77.8%-90.9%)，特异性为86.9% （95% CI, 79.7%-94%）。在100%（30/30）的LDN患者和63%（38/60）的NLDN患者中观察到长度依赖性EDX模式。38例NLDN患者中，SRAR超过0.33的占78.9%（30/38）。讨论：SRAR在神经病变的电生理评估中似乎是有用的。除了通常的诊断标准外，SRAR值为0.33可能强烈提示NLDN，如SNN或CIDP。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Muscle & Nerve 医学-临床神经学

CiteScore

6.40

自引率

5.90%

发文量

287

审稿时长

3-6 weeks

期刊介绍： Muscle & Nerve is an international and interdisciplinary publication of original contributions, in both health and disease, concerning studies of the muscle, the neuromuscular junction, the peripheral motor, sensory and autonomic neurons, and the central nervous system where the behavior of the peripheral nervous system is clarified. Appearing monthly, Muscle & Nerve publishes clinical studies and clinically relevant research reports in the fields of anatomy, biochemistry, cell biology, electrophysiology and electrodiagnosis, epidemiology, genetics, immunology, pathology, pharmacology, physiology, toxicology, and virology. The Journal welcomes articles and reports on basic clinical electrophysiology and electrodiagnosis. We expedite some papers dealing with timely topics to keep up with the fast-moving pace of science, based on the referees'' recommendation.