Cognitive and neurodevelopmental disorders in spinal muscular atrophy type I at the time of disease-modifying therapies

After treatment with new disease-modifying therapies, cognitive and neurodevelopmental aspects have been observed in individuals with spinal muscular atrophy (SMA). Emerging evidence suggests that children with SMA type 1 may experience cognitive, language, and behavioural delays, with reported rates of neurodevelopmental difficulties ranging from 9% to 60%. However, the evidence is inconclusive because of diagnostic inconsistencies and challenges in defining and categorizing cognitive, behavioural, and broader neurodevelopmental disorders. Some of these challenges are related to the difficulties in assessing children with severe motor, communication, or fatigue-related impairments. Despite neurodevelopmental and cognitive aspects being relatively frequent in SMA type 1, the lack of systematic assessment methodologies and the presence of motor-related testing biases hinder efforts to distinguish true neurodevelopmental disorders from the secondary effects of motor limitations, thus highlighting the unmet need of dedicated tools.