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#apaperaday: Early motor, cognitive, language, behavioural and social emotional development in infants and young boys with Duchenne Muscular Dystrophy- A systematic review

In today’s #apaperaday, Prof. Aartsma-Rus reads and comments on the paper titled: Early motor, cognitive, language, behavioural and social emotional development in infants and young boys with Duchenne Muscular Dystrophy- A systematic review

A paper a day today by Hoskens et al in the European Journal of Paediatric Neurology on developmental delays in motor skills, cognition, language, behavioral and social emotional skills in young Duchenne boys. DOI: 10.1016/j.ejpn.2024.07.003

Duchenne is mainly known as a disease of muscular dystrophy and thus associated with motor developmental delays and loss of motor function. However, dystrophin is also expressed in brain and there are additional delays and problems patients can encounter.

How these delays affect young boys with Duchenne on the various domains (motor, cognition, language, behavior and social emotional) has not been well described. Here, authors performed a systematic review on these aspects in patients up to 6 years.

They found thousands of papers, of which 71 were relevant to their inquiry and 55 were of sufficient quality for the purpose of the study. Data were extracted from these studies. When studies included also older patients, only the data up to 6 years was taken into account.

46/55 studies reported on motor development, and showed milestone delays (especially for sitting, walking and stair climbing) and weakness. Both gross and fine motor skills were affected, but gross motor skills to a higher extent. Patients performed less in timed function tests.

Gait and stride differed from boys without Duchenne. Less studies looked at cognition (19/55). These revealed large heterogeneity, with some boys having normal cognition, borderline intelligence (1 in 6), others learning difficulties (1 in 4) or intellectual disability (1 in 6)

Language development was studied in 12 studies & revealed delays in milestones for verbal expression & learning to read. Behavior was studied in 10 studies & showed delays in adaptive behaviour. Social emotional development was studied in 9 studies, also here patients had delays.

For cognitive, learning, behavior & social development, patients with deletions beyond intron 44 (i.e. likely no functional dp140 isoform + no functional full length brain dystrophin) did worse than those with mutations before intron 44 (no functional full length dystrophin)

However, there was more heterogeneity for these domains, with some patients not being affected, than for the motor domain, where everyone was affected. Authors discuss that patients improve until they are 6 for each domain. For the motor skills they plateau around this age.

Note that while patients improve until age 6-7 for motor skills, the deficit compared to healthy peers increases (they improve more). Authors discuss that their study was challenging, as there is only limited literature on young Duchenne patients.

They argue more work is needed. They also stress that healthcare professionals should be triggered to consider Duchenne when presented with the combination of developmental delays and that patients should receive not only support for the motor problems but also the other delays.

Early recognition can help to offer support with e.g. learning strategies for learning how to read and how to cope with behavioral challenges. While this topic is still poorly studied with the BIND project, a lot more work has been done.