Respiratory tests are fundamental for monitoring respiratory function in ALS, and essential in clinical trials. Slow vital capacity (SVC) was canceled in some countries to prevent COVID-19 transmission. This study aimed to test phrenic nerve motor responses as an option to SVC in clinical trials. It found that contrary to SVC, meanPhrenAmpl is non-volitional and not associated with aerosolization risk. https://www.tandfonline.com/doi/full/10.1080/21678421.2021.1895842?scroll=top&needAccess=true