P.18 Comparison of the performance of the upper limb module in children with Becker muscular dystrophy, Duchenne muscular dystrophy and healthy controls

Abstract

Becker muscular dystrophy (BMD) is an X-linked recessive disorder, a type of dystrophinopathy. BMD is a milder form of Duchenne Muscular Dystrophy (DMD). Both diseases are characterised by progressing muscle weakness. Upper limb function is not routinely assessed in ambulant children in these conditions; however, it can be of great importance. It is hoped that advances in gene therapy will result in boys with DMD having significant improvements and therefore having a presentation trajectory more like boys with BMD. It is therefore of great importance both clinically and in research trials to have validated outcome measures to be able to successfully monitor improvements and plateaus in this cohort. The Performance of Upper Limb Module (PUL 2.0) is a validated outcome measure for DMD predominantly used to assess change in upper limb function in non-ambulant boys over time. PUL 2.0 data was collected for 63 children in total. Twenty-one of these children with BMD were compared to 21 age-matched children with DMD and 21 healthy controls. A correlation analysis will be used to explore the differences, taking weight of the boys into account. Functional scores (using the Hammersmith functional motor score) for the boys with BMD will be explored and compared to the PUL scores as well as differences in the height of the boys. The initial analysis demonstrates a ceiling effect for the PUL in BMD, with 18/21 achieving full marks, with them more closely aligning with healthy controls than boys with DMD. In future clinical trials for boys with DMD including outcome measures without a ceiling effect will allow all improvements to be captured. It is important to establish if boys with BMD have functional difficulties that the PUL is not capturing. This study is a part of a larger team approach to understanding more about outcome measures in BMD.