Calma Aicee Dawn, Pavey Nathan, Silva Claudia Santos, Tsuji Yukiko, Van den Bos Mehdi A J, Farrar Michelle A, Menon Parvathi, Vucic Steve
Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, New South Wales, Australia.
Department of Neurosciences and Mental Health, Unidade Local de Saúde de Santa Maria, Lisbon, Portugal.
Muscle Nerve. 2025 Oct;72(4):616-624. doi: 10.1002/mus.28480. Epub 2025 Jul 18.
INTRODUCTION/AIMS: Far field potentials (FFP) have been proposed as a reliable neurophysiological prognostic biomarker in amyotrophic lateral sclerosis (ALS). This study evaluates the diagnostic utility of ulnar nerve FFP in ALS.
Comprehensive peripheral neurophysiological assessments were conducted in 62 ALS and 43 ALS-mimicking disorder participants. The ulnar nerve was stimulated at the wrist, recording motor responses over the abductor digit minimi (ADM) muscle. Conventional compound muscle action potentials (CMAP), FFP, and near field potential amplitudes were recorded, alongside the split-hand index, neurophysiological index, motor unit number estimation (MScanFit-MUNE), and motor unit index (MUNIX). Diagnostic utility was evaluated using receiver operating characteristic (ROC) analysis.
In ALS, FFP amplitude was significantly lower (5.07 ± 0.36 mV) compared to ALS mimics (8.25 ± 0.40 mV, p < 0.001). FFP amplitude exhibited a moderate-to-strong correlation with neurophysiological biomarkers, including CMAP amplitude (ρ = 0.77, p < 0.001), split-hand index (ρ = 0.53, p < 0.001), neurophysiological index (ρ = 0.52, p < 0.001), MUNIX (ρ = 0.69, p < 0.001), and MScanFit-MUNE (ρ = 0.66, p < 0.001). Weak-to-moderate correlations were also observed with clinical measures of disease progression, including upper limb muscle strength, ALS functional rating score-revised (ALSFRS-R) and the rate of decline in the ALSFRS-R fine motor subscore. ROC analysis demonstrated that FFP amplitude reliably distinguished ALS from mimicking disorders (AUC = 0.80, 95% CI: 0.71-0.89), with consistent diagnostic accuracy across ALS phenotypes.
The diagnostic capability of FFP amplitude was comparable to established neurophysiological biomarkers utilized in ALS. It is a promising prognostic and diagnostic biomarker for ALS. Its simplicity and reproducibility complement traditional neurophysiological measures, offering potential for clinical application in ALS diagnosis and monitoring.
引言/目的：远场电位（FFP）已被提议作为肌萎缩侧索硬化症（ALS）中一种可靠的神经生理学预后生物标志物。本研究评估尺神经FFP在ALS中的诊断效用。
对62例ALS患者和43例疑似ALS疾病的参与者进行了全面的周围神经生理学评估。在腕部刺激尺神经，记录小指展肌（ADM）的运动反应。记录常规复合肌肉动作电位（CMAP）、FFP和近场电位幅度，同时记录裂手指数、神经生理指数、运动单位数量估计（MScanFit-MUNE）和运动单位指数（MUNIX）。使用受试者操作特征（ROC）分析评估诊断效用。
在ALS患者中，FFP幅度（5.07±0.36mV）显著低于疑似ALS疾病的患者（8.25±0.40mV，p<0.001）。FFP幅度与神经生理学生物标志物呈中度至强相关性，包括CMAP幅度（ρ=0.77，p<0.001）、裂手指数（ρ=0.53，p<0.001）、神经生理指数（ρ=0.52，p<0.001）、MUNIX（ρ=0.69，p<0.001）和MScanFit-MUNE（ρ=0.66，p<0.001）。还观察到与疾病进展的临床指标存在弱至中度相关性，包括上肢肌肉力量、修订的ALS功能评定量表（ALSFRS-R）以及ALSFRS-R精细运动子量表的下降率。ROC分析表明，FFP幅度能够可靠地将ALS与疑似疾病区分开来（AUC=0.80，95%CI：0.71-0.89），在不同ALS表型中诊断准确性一致。
FFP幅度的诊断能力与ALS中使用的既定神经生理学生物标志物相当。它是一种有前景的ALS预后和诊断生物标志物。其简单性和可重复性补充了传统神经生理学测量方法，为ALS诊断和监测的临床应用提供了潜力。
