Navigating new motor function trajectories: Consensus recommendations for assessment in the era of newborn screening and early treatment in SMA

BACKGROUND: Approved disease modifying treatments (DMTs) and the implementation of newborn screening for spinal muscular atrophy (SMA) have allowed individuals treated early to gain new motor abilities and achieve more typical motor milestones. In this changing landscape, current motor function outcome measures (MF-OMs) used in SMA clinical practice may no longer be sufficiently sensitive enough to optimally quantify new disease trajectories and evolving functional progression. OBJECTIVE: To develop a consensus-derived recommendation for MF-OMs to be used in assessing infants and children living with SMA who were treated with DMTs very early in life. METHODS: A modified Delphi methodology which included three web-based surveys and virtual conferences was conducted with an international group of multidisciplinary experts treating infants and children living with SMA who were treated early. Community input was also collected via semi-structured interviews. RESULTS: A consensus-derived recommendation for MF-OMs to be routinely administered in early treated infants and children living with SMA was developed. Consensus recommendations included both SMA-specific and non SMA-specific MF-OMs for five age periods. MF-OMs were inclusive of Clinician-Reported, Caregiver/Patient-Reported, and Performance/Functional Outcome Measures. Recommendations on optimal assessment frequency varied across age periods from quarterly to bi-annually. CONCLUSIONS: Clinicians with expertise in SMA achieved consensus on establishing relevant MF-OMs to implement from infancy through childhood to track motor progress in early treated infants. Routine data collection using recommended MF-OMs will facilitate cohort comparison for research collaborations to better understand new disease trajectories and motor progression of this population.