Comment: Plateaus and reversals in ALS disease course or limitations of trial design?

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive disease of motor neurons, resulting in worsening weakness of voluntary muscles until death from respiratory failure occurs after on average 3 years. Bedlack et al.1found that as many as 25% of patients did not show disease progression on the Amyotrophic Lateral Sclerosis Functional Rating Scale–revised (ALSFRS-R) over the course of 6 months, and 16% over 12 months. Small reversals over shorter periods were also common (14%).