The current lack of patient-centered, sensitive measures (based on motor function and item difficulty hierarchy) that are suited for repeated assessments in infants and young children with NMD represents a major obstacle to the rapid translation of promising therapeutic interventions from preclinical models to clinical research studies. Multiple clinical outcome measures used at a single time-point for capturing a child s functional status are burdensome, difficult to interpret and do not provide us with comprehensive, meaningful information to detect changes following an intervention [3]. Psychometric measures that can be completed by parents make it possible to collect a considerable amount of data over many time-points rather than being limited to a single clinical observation. Moreover, a parent-observational measure that focuses on their child s functional performance in their real-life will maximize the ecological validity of measures of motor development used for clinical trials.