Title : Quantitative evaluation of factors contributing to the results of 3hz RNS test on ALS patients
Abstract:
Introduction: Previous studies have suggested that therapeutic treatments aimed at preserving neuromuscular junction (NMJ) may play an imperative role in fighting against amyotrophic lateral sclerosis (ALS). However, as far as repetitive nerve stimulation (RNS) test, a technique to evaluate NMJ function, is concerned, factors contributing to its results and their respective contributions have not yet been fully elucidated.
Methods: A total of 626 patients who diagnosed as ALS were enrolled in this study. Data of their clinical and electrophysiological indicators are divided into training set(collected from June 2016 to December 2022) and test set(collected from January 2023 to August 2023). Stepwise regression was used in independent variable selection and model building.
Results: 42% patients have a decrement larger than 10% and 23.9% have a decrement larger than 15%. Onset age, gender, onset site, forced vital capacity(FVC) and motor unit potential(MUP) duration are independent factors contributing to the results of RNS test on the accessory nerve. MUP duration has the greatest impact on decremental response, followed by FVC and onset age. The expected decrement in the female is larger than in the male. Upper limb onset contributes to the decrement more than lower limb onset and bulbar onset.
Discussion: The results of RNS test on the accessory nerve may be suitable to serve as a biomarker to monitor respiratory function in ALS patients. Independent factors need to be considered in stratified randomization for clinical trials aimed at targeting NMJ in ALS patients.
Audience Take Away Notes:
- The abnormality rates of 3Hz RNS test result, and relationship between the decrement and either clinical indicators(including gender, onset site, diagnostic level, age at onset, disease duration, BMI, FVC, ALSFRS-R score, disease progression rate) or electrophysiological indicators(including MUP duration, MUP amplitude, polyphasia) were analyzed in current study with a large sample size.
- 2 regression models about the results of RNS test on the accessory nerve have been built with good and stable prediction performance, which can be recalibrated for patients from other cohorts.
- MUP duration, gender and onset site are important factors contributing to the decremental response in ALS patients, which need to be considered in stratified randomization for clinical trials aimed at targeting NMJ in ALS patients. As for individuals, onset age, gender, and onset site are settled, so NMJ function in the accessory nerve is mainly affected by MUP duration and FVC.
