Zhi-Li Wang1, Mingsheng Liu1, Zhengyi Cai1, Qingyun Ding1, Youfang Hu1, Liying Cui1,2. 1. Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and. 2. Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China.
Abstract
OBJECTIVE: To determine the practical diagnostic utility of split-hand index (SI) values calculated from F-wave persistence (SIFP) and the F/M amplitude ratio (SIF/M) for differentiating patients with amyotrophic lateral sclerosis (ALS) from other conditions. Methods: This prospective study recruited consecutive patients from Peking Union Medical College Hospital, China, between June 2019 and December 2019. Patients 18-80 years old who had clinical neuromuscular symptoms affecting the upper limbs and required electrophysiological examinations to aid diagnosis were eligible. Compound muscle action potentials (CMAPs) and F-waves recorded from the abductor pollicis brevis (APB), first dorsal interosseous muscle (FDI), and abductor digiti minimi (ADM) were examined. SIFP and SIF/M were calculated as: SI = (APB × FDI)/ADM. The sensitivity and specificity of SIFP and SIF/M in differentiating ALS from non-ALS conditions were derived using receiver operating characteristic (ROC) curves. Results: A total of 309 participants, comprising 91 (29.4%) with ALS and 218 (70.6%) with other neuromuscular disorders, were enrolled after 54 were excluded. SIFP was significantly reduced and SIF/M increased in the ALS group compared with the non-ALS group (p < 0.001). By ROC curve analysis, an SIFP cutoff of 73.3 showed 85.7% sensitivity and 80.7% specificity for differentiating ALS from non-ALS. SIF/M and SICMAP showed lower sensitivity (67% and 75.8%, respectively, p < 0.001) than SIFP for ALS diagnosis. SIFP and SIF/M combined did not outperform SIFP alone. Conclusion: SIFP could be a sensitive, noninvasive neurophysiological diagnostic marker for ALS patients with affected upper limbs. In particular, an SIFP value of 73.3 might be the optimal cutoff for diagnosing ALS.
OBJECTIVE: To determine the practical diagnostic utility of split-hand index (SI) values calculated from F-wave persistence (SIFP) and the F/M amplitude ratio (SIF/M) for differentiating patients with amyotrophic lateral sclerosis (ALS) from other conditions. Methods: This prospective study recruited consecutive patients from Peking Union Medical College Hospital, China, between June 2019 and December 2019. Patients 18-80 years old who had clinical neuromuscular symptoms affecting the upper limbs and required electrophysiological examinations to aid diagnosis were eligible. Compound muscle action potentials (CMAPs) and F-waves recorded from the abductor pollicis brevis (APB), first dorsal interosseous muscle (FDI), and abductor digiti minimi (ADM) were examined. SIFP and SIF/M were calculated as: SI = (APB × FDI)/ADM. The sensitivity and specificity of SIFP and SIF/M in differentiating ALS from non-ALS conditions were derived using receiver operating characteristic (ROC) curves. Results: A total of 309 participants, comprising 91 (29.4%) with ALS and 218 (70.6%) with other neuromuscular disorders, were enrolled after 54 were excluded. SIFP was significantly reduced and SIF/M increased in the ALS group compared with the non-ALS group (p < 0.001). By ROC curve analysis, an SIFP cutoff of 73.3 showed 85.7% sensitivity and 80.7% specificity for differentiating ALS from non-ALS. SIF/M and SICMAP showed lower sensitivity (67% and 75.8%, respectively, p < 0.001) than SIFP for ALS diagnosis. SIFP and SIF/M combined did not outperform SIFP alone. Conclusion: SIFP could be a sensitive, noninvasive neurophysiological diagnostic marker for ALS patients with affected upper limbs. In particular, an SIFP value of 73.3 might be the optimal cutoff for diagnosing ALS.