Fine motor skill and expressive language in minimally verbal and verbal school-aged autistic children

Fine motor skill is associated with expressive language outcomes in infants who have an autistic sibling and in young autistic children. Fewer studies have focused on school-aged children even though around 80% have motor impairments and 30% remain minimally verbal (MV) into their school years. Moreover, expressive language is not a unitary construct, but it is made up of components such as speech production, structural language, and social-pragmatic language use. We used natural language sampling to investigate the relationship between fine motor and speech intelligibility, mean length of utterance and conversational turns in MV and verbal autistic children between the ages of 4 and 7 while controlling for age and adaptive behavior. Fine motor skill predicted speech production, measured by percent intelligible utterances. Fine motor skill and adaptive behavior predicted structural language, measured by mean length of utterance in morphemes. Adaptive behavior, but not fine motor skill, predicted social-pragmatic language use measured by number of conversational turns. Simple linear regressions by group corrected for multiple comparisons showed that fine motor skill predicted intelligibility for MV but not verbal children. Fine motor skill and adaptive behavior predicted mean length of utterance for both MV and verbal children. These findings suggest that future studies should explore whether MV children may benefit from interventions targeting fine motor along with speech and language into their school years.