Abstracts are provided in the language submitted.

Aim: A scoping review was conducted to summarize the current knowledge on brain involvement in spinal muscular atrophy (SMA) types I-IV, focusing on magnetic resonance imaging (MRI). Methods: Two databases (PubMed and EMBASE) were searched to retrieve relevant articles on brain imaging in SMA censoring to July 2021. Full-text articles published in peer-reviewed journals or abstracts accepted to conferences in English and French were included. Results: Twelve articles were identified describing a total of 39 patients [11d-41y, type 0 (n=5), type 1 (n=4), type 2 (n=2), type 3 (n=22), type 4 (n=6)]. All were class IV studies for risk of bias. In individuals with early onset SMA, cortical and subcortical brain abnormalities in white matter, basal ganglia, thalamus, hippocampus, and high intensity areas around lateral ventricles and thalami were reported. In individuals with late-onset SMA, reduced cerebellar and lobular volume as well as increased grey matter density in motor areas were observed. Interpretation: Limited data on brain imaging shows cortical and subcortical involvement in early and late onset SMA. Further rigorous studies are needed to determine the extent and prevalence of structural brain changes across SMA types.

Nancy Mugisha