Neurophysiological index is associated with the survival of patients with amyotrophic lateral sclerosis

Abstract

ObjectiveTo investigate the association between Neurophysiological Index (NI) and the survival of patients with Amyotrophic Lateral Sclerosis (ALS). MethodsPatients diagnosed with ALS in the Department of Neurology, West China Hospital, Sichuan University from May 2015 to May 2017 were enrolled in this study, and then were followed up every 3 months until 31st May 2018. According to the mean NI values, the participants were categorized into high NI and low NI groups. Differences between groups were compared with parametric or non-parametric test, whichever was more appropriate. Kaplan-Meier method and Cox regression model were used to calculate the survival analysis. ResultsOne hundred and ninety one sporadic ALS patients including 78 female and 113 male were included in this study. Among them, 5 (2.6%) patients were lost to follow-up, 79 patients were still alive while 102 patients died at the last follow up. The median survival time from symptom onset to death was 33 months, as estimated by Kaplan-Meier analysis. ALS patients with lower NI exhibited to have shorter median survival time compared to the patients with high NI. Through multivariate Cox regression analysis, NI, the revised ALS functional rating scale (ALSFRS-R), diagnostic delay and age at disease onset were found to be associated with the survival of ALS patients. ConclusionOur findings indicate that NI provides a single number that seems to associate with the survival of ALS. SignificanceNI is readily available and reproducible, and it could be utilized as a potential biomarker for survival in further multicenter clinical trials in ALS.