The HFMSE is a validated measure that has been used in several clinical studies to evaluate the motor function of children with SMA. The HFMSE adds 13 clinically relevant items from the Gross Motor Function Measure (GMFM), including lying/rolling, crawling/kneeling, standing, and walking/running/jumping. The measure has 33 items, each scored from 0 to 2. Higher scores indicate higher levels of achievement.1,2