Abstract
Objective: The objectives of this work were to identify the characteristics of repetitive nerve stimulation (RNS) in patients with amyotrophic lateral sclerosis (ALS) and further verify the electrophysiological exclusion criteria of ALS.Methods: A total of 150 patients with ALS who were admitted to the Department of Neurology of Renmin Hospital of Wuhan University from January 2015 to December 2018 were enrolled. Clinical and electrophysiological data of the enrolled patients were collected. The differences in the amplitudes of the compound muscle action potential (CMAP) between the trapezius muscle (Trap) and the abductor digiti minimi (ADM) in low-frequency RNS were compared. Furthermore, we analyzed the associations between decremental responses and gender, onset age, duration of disease, onset site, Amyotrophic Lateral Sclerosis Functional Rating Scale—Revised (ALSFRS-R), disease progression rate, and CMAP amplitude.Results: A significant decrement (≥20%) in at least one muscle was observed in 11.3% of the ALS patients, while decrements (≥10%) in at least one muscle were observed in 41.3%. The decremental percentage in the trapezius muscle was significantly higher than that in the abductor digiti minimi (P < 0.001). The onset age, duration of disease, onset site, and disease progression rate did not affect decremental responses. The decremental responses in RNS were more significant in ALS patients with low ALSFRS-R scores (P = 0.01). Moreover, there was a positive linear correlation between the CMAP amplitude and the decremental percentage of Trap and ADM in ALS patients.Conclusions: CMAP decremental responses in RNS were common in ALS patients, suggesting abnormalities of neuromuscular junctions (NMJs). It is worthy of further discussion whether to consider a decrement >20% in RNS as a diagnostic exclusion criterion for ALS.
Highlights
Amyotrophic lateral sclerosis (ALS), the most quintessential motor neuron disease, affects both upper and lower motor neurons, and leads to progressive muscle atrophy and weakness [1]
Mulder et al [2] originally reported that decremental responses in low-frequency repetitive nerve stimulation (RNS) tests were observed in ALS patients
Later studies demonstrated that a decrement >20% was observed in ALS patients [4, 7, 8]
Summary
Amyotrophic lateral sclerosis (ALS), the most quintessential motor neuron disease, affects both upper and lower motor neurons, and leads to progressive muscle atrophy and weakness [1]. Mulder et al [2] originally reported that decremental responses in low-frequency repetitive nerve stimulation (RNS) tests were observed in ALS patients. The electrophysiological diagnostic criteria of ALS revised by the World Federation of Neurology Research Group on Motor Neuron Diseases pointed out that a significant compound muscle action potential (CMAP) decrement >20% in RNS was a diagnostic exclusion criterion for ALS [6]. Later studies demonstrated that a decrement >20% was observed in ALS patients [4, 7, 8]. The amplitude and incidence of decremental responses and the criteria for the positive decrement were inconsistent among previous research
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
