Exploring the variability in spoken language comprehension, speech and functional communication in children with GNAO1-related disorder: a case series

AIM: GNAO1-related disorder (GNAO1-RD) is ultra-rare and clinically heterogeneous. Often, children with GNAO1-RD have (severe) motor impairments, which may lead to an underestimation of their communication abilities. To help these children achieve their full potential in daily life, it is essential to understand their communicative abilities and limitations. In this study, we aimed to investigate spoken language comprehension (SLC), speech and functional communication. METHODS: A cohort study including children with GNAO1-RD. SLC and functional communication were assessed using the Computer-Based instrument for Low motor Language Testing (C-BiLLT) and Communication Function Classification System (CFCS), respectively. Disease severity and motor functions were assessed using the GNAO1-Severity Scale, Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS) and Viking Speech Scale (VSS). RESULTS: (7) = -0,688, p = 0.040), indicating that better SLC correlated with better functional communication. No significant associations were found between C-BiLLT scores and GNAO1-Severity Scale scores, GMFCS, MACS or VSS levels. INTERPRETATION: This study shows considerable heterogeneity of communication performance in children with GNAO1-RD. Children with better SLC communicate more effectively in daily life. The level of SLC, however, was not related to the severity of motor impairments. These findings underline the need for tailored approaches to support communication in daily life.