Measure eSVC/sSVC and ALS Functional Rating Scale-Revised (ALSFRS-R) twice monthly up to 6 months via AHT in ALS subjects between quarterly in-clinic eSVC/sSVC assessments in a multicenter, prospective, longitudinal, observational clinical study [NCT05106569] using ZEPHYRx™ Breathe Easy software and Remote Respiratory Monitoring™/Provider Dashboard.

eSVC/sSVC were measured longitudinally via AHT as previously reported. In this analysis, ALSFRS-R changes were examined longitudinally alongside eSVC/sSVC in-clinic or via smartphone. Delta eSVC/sSVC and ALSFRS-R total trajectories were analyzed with a linear mixed methods model involving baseline covariates.

Ninety-eight subjects (NIV started at baseline=21, NIV started post-baseline=36, NIV non-users=41) consented to participate; 71 (72.5%) subjects completed a minimum of 6 AHT. Mean monthly decline rate for ALSFRS-R total score (−1.3 units/month [Q1, Q3=−1.8, −0.5]) of NIV non-users was statistically significantly different (p=0.001) from the monthly decline rate (−2.2 units/month [Q1, Q3=−2.8, −1.2]) for subjects who were not on NIV at baseline but started later.

This first prospective, longitudinal, observational study of smartphone–mediated AHT eSVC/sSVC measurement identified statistically significant differences in monthly decline of eSVC/sSVC and ALSFRS-R total score between subjects not requiring NIV and those on NIV vs subjects not on NIV at baseline who started NIV during the study. NIV use, due to its potential to alter both respiratory and motor function, needs to be more carefully captured in clinical trials and clinical studies to permit correct conclusions regarding pharmacological and device interventions.