131P Social communication abilities in treated children with spinal muscular atrophy type 1 (SMA1): a cross-sectional study from two tertiary neuromuscular centres

There is emerging evidence that SMA1 children treated with disease modifying therapies (DMTs) develop expressive language abilities although these do not follow typical trajectories. Very little is known about other aspects of communication, including social communication abilities. We conducted a cross-sectional study aiming to investigate parents-reported expressive language and social communication skills in SMA1 patients treated with DMTs at two Neuromuscular Centres, the Dubowitz Neuromuscular Centre, London (UK) and the Centro Clinico Nemo Pediatrico, Rome (Italy). Parents of SMA1 children were asked to complete the MacArthur-Bates Communicative Development Inventory (MB-CDI) for children aged 8months+, to investigate the developing abilities in early language, and the Social Communication Questionnaire (SCQ) for children aged 4years+, to identify potential social communication difficulties. For the SCQ, a cut-off ≥ 11 was selected to improve sensitivity and reduce the likelihood of false negatives. Fifteen parents agreed to complete the MB-CDI (age range: 2 years 2 months – 6 years 9 months). Results demonstrated the acquisition of some verbal skills in 13/15, although with scores below normal ranges. Thirty-seven parents agreed to complete the SCQ (age range: 4 years 0 months – 9 years 0 months). Twenty-one/37 parents were unable to answer one or more questions (range 1–22) due to their child being nonverbal and/or not strong enough to perform the action(s) so, those items were excluded from the total score. Four/37 (11%) showed a total SCQ score ≥11, suggesting the need of further investigations for autism spectrum disorder. Three/4 had completed the MB-CDI and were among the children able to say the lowest number of words. Other areas of concern emerging from the SCQ included routines/ritualized patterns of behaviour (14/37, 38%), and hyperreactivity to sensory input (5/37, 13%). Treated SMA1 children can acquire expressive language skills, although this can be delayed. A noteworthy percentage of them also present with social communication difficulties later on in life, especially when expressive language is more severely affected. Large prospective studies are warranted to better characterize the spectrum of language and social communication abilities in this population.