{"title":"F-waves responses derived from low-intensity electrical stimulation: A method to explore split-hand pathogenesis","authors":"Miguel Lopes , Michael Swash , Mamede de Carvalho","doi":"10.1016/j.neucli.2024.103018","DOIUrl":null,"url":null,"abstract":"<div><h3>Objectives</h3><div>The “split-hand syndrome” is a common clinical sign in amyotrophic lateral sclerosis (ALS), being characterized by more severe atrophy of the hand muscles on the radial side of the hand compared to the ulnar side. We aimed to investigate possible physiological differences between relevant hand muscles using low-intensity F-wave stimulation to assess spinal motoneuron excitability.</div></div><div><h3>Methods</h3><div>We recruited 36 healthy volunteers. F-waves were recorded from the abductor pollicis brevis (APB), first dorsal interosseous (FDI) and abductor digiti minimi (ADM), using 20 supramaximal stimuli followed by 20 stimuli at a low-intensity required to obtain M-waves with 10 % amplitude of maximal CMAP. We evaluated the following F-wave parameters: F-M latency, chronodispersion, persistence, amplitude, F/CMAP amplitude ratio and number of F-wave repeaters (with low-intensity). In 10 subjects, low-intensity stimulation F-waves were compared after 20 and 50 stimuli in each muscle.</div></div><div><h3>Results</h3><div>Low-intensity stimulation resulted in lower F-wave amplitude and persistence and higher F/CMAP amplitude ratios. There were no significant differences in F-wave latencies and chronodispersion. When comparing the three muscles, we found higher F-wave persistence and F/CMAP amplitude ratios when recording over the ADM and APB compared to the FDI. We also found a higher number of F-wave repeaters in the ADM with low-intensity stimulation. Results from 20 to 50 low-intensity stimuli were similar.</div></div><div><h3>Discussion</h3><div>A small number of low-intensity stimuli is appropriate to study F-wave latencies and chronodispersion. We found differences in some physiological properties of the ADM spinal motoneuron pool compared to other hand muscles.</div></div>","PeriodicalId":19134,"journal":{"name":"Neurophysiologie Clinique/Clinical Neurophysiology","volume":"54 6","pages":"Article 103018"},"PeriodicalIF":2.7000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Neurophysiologie Clinique/Clinical Neurophysiology","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0987705324000765","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CLINICAL NEUROLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Objectives
The “split-hand syndrome” is a common clinical sign in amyotrophic lateral sclerosis (ALS), being characterized by more severe atrophy of the hand muscles on the radial side of the hand compared to the ulnar side. We aimed to investigate possible physiological differences between relevant hand muscles using low-intensity F-wave stimulation to assess spinal motoneuron excitability.
Methods
We recruited 36 healthy volunteers. F-waves were recorded from the abductor pollicis brevis (APB), first dorsal interosseous (FDI) and abductor digiti minimi (ADM), using 20 supramaximal stimuli followed by 20 stimuli at a low-intensity required to obtain M-waves with 10 % amplitude of maximal CMAP. We evaluated the following F-wave parameters: F-M latency, chronodispersion, persistence, amplitude, F/CMAP amplitude ratio and number of F-wave repeaters (with low-intensity). In 10 subjects, low-intensity stimulation F-waves were compared after 20 and 50 stimuli in each muscle.
Results
Low-intensity stimulation resulted in lower F-wave amplitude and persistence and higher F/CMAP amplitude ratios. There were no significant differences in F-wave latencies and chronodispersion. When comparing the three muscles, we found higher F-wave persistence and F/CMAP amplitude ratios when recording over the ADM and APB compared to the FDI. We also found a higher number of F-wave repeaters in the ADM with low-intensity stimulation. Results from 20 to 50 low-intensity stimuli were similar.
Discussion
A small number of low-intensity stimuli is appropriate to study F-wave latencies and chronodispersion. We found differences in some physiological properties of the ADM spinal motoneuron pool compared to other hand muscles.
期刊介绍:
Neurophysiologie Clinique / Clinical Neurophysiology (NCCN) is the official organ of the French Society of Clinical Neurophysiology (SNCLF). This journal is published 6 times a year, and is aimed at an international readership, with articles written in English. These can take the form of original research papers, comprehensive review articles, viewpoints, short communications, technical notes, editorials or letters to the Editor. The theme is the neurophysiological investigation of central or peripheral nervous system or muscle in healthy humans or patients. The journal focuses on key areas of clinical neurophysiology: electro- or magneto-encephalography, evoked potentials of all modalities, electroneuromyography, sleep, pain, posture, balance, motor control, autonomic nervous system, cognition, invasive and non-invasive neuromodulation, signal processing, bio-engineering, functional imaging.