Differences in non-word repetition, oral-motor performance and auditory discrimination in children with childhood apraxia of speech (CAS) and speech motor delay (SMD)

Non-word repetition (NWR) is a frequently used task in speech and language assessments. This study investigated NWR performance in children with childhood apraxia of speech (CAS) and speech motor delay (SMD), examining its relation to auditory discrimination (AD) and oral motor performance. Participants were 54 children with persistent speech-sound disorders (SSD) (31 with CAS and 23 with SMD) and 39 children with typical speech development (TSD) aged 6-16 years. Assessments of word naming, NWR, AD, and oral-motor performance were conducted. Percentage consonants correct (PCC), and percentage vowels correct (PVC) were calculated from phonetic transcriptions. The results revealed a difference between children with SSD and children with TSD on all variables and also revealed some differences between children with CAS and children with SMD. Children with CAS had a lower PCC and PVC score on NWR and a lower AD score than those with SMD. More parents of children with CAS reported difficulties with reading and writing. A large proportion of both children with SMD and children with CAS were found to have orofacial dysfunction. Our findings suggest that assessing AD skills and oral-motor skills is important for understanding the underlying difficulties of motor speech disorders in children. Our results indicate differences related to motor planning and motor execution, underscoring the importance of broad assessment approaches to facilitate accurate diagnoses and tailored interventions.