Oral motor deficits in speech-impaired children with autism

Matthew K Belmonte,Lisa George,Prathibha Karanth,Reema Muneer,Ruth Cherian,Tanushree Saxena-Chandhok

doi:10.3389/fnint.2013.00047

Abstract

Absence of communicative speech in autism has been presumed to reflect a fundamental deficit in the use of language, but at least in a subpopulation may instead stem from motor and oral motor issues. Clinical reports of disparity between receptive vs. expressive speech/language abilities reinforce this hypothesis. Our early-intervention clinic develops skills prerequisite to learning and communication, including sitting, attending, and pointing or reference, in children below 6 years of age. In a cohort of 31 children, gross and fine motor skills and activities of daily living as well as receptive and expressive speech were assessed at intake and after 6 and 10 months of intervention. Oral motor skills were evaluated separately within the first 5 months of the child's enrolment in the intervention programme and again at 10 months of intervention. Assessment used a clinician-rated structured report, normed against samples of 360 (for motor and speech skills) and 90 (for oral motor skills) typically developing children matched for age, cultural environment and socio-economic status. In the full sample, oral and other motor skills correlated with receptive and expressive language both in terms of pre-intervention measures and in terms of learning rates during the intervention. A motor-impaired group comprising a third of the sample was discriminated by an uneven profile of skills with oral motor and expressive language deficits out of proportion to the receptive language deficit. This group learnt language more slowly, and ended intervention lagging in oral motor skills. In individuals incapable of the degree of motor sequencing and timing necessary for speech movements, receptive language may outstrip expressive speech. Our data suggest that autistic motor difficulties could range from more basic skills such as pointing to more refined skills such as articulation, and need to be assessed and addressed across this entire range in each individual.

Highlights

Deficits in communication have long been recognised as an essential characteristic of autism, earning a place in the triad of diagnostic signs
Motor-intact and motorimpaired groups were distinguished by a discriminant with positive loading on receptive-expressive language disparity and oral motor skills, and somewhat on gross motor skills which were in turn highly correlated with fine motor skills
Following the period of intervention the motor-impaired group did not achieve as proficient post-intervention oral motor function, and across the entire sample the learning rates for both receptive and expressive language were highly correlated with the learning rate for oral motor skills

Summary

Introduction

Deficits in communication have long been recognised as an essential characteristic of autism, earning a place in the triad of diagnostic signs. As autism is a behaviourally diagnosed syndrome with a great degree of heterogeneity in presentation, it’s likely to admit many biological causes, with different combinations of these biological causal mechanisms converging into one and the same set of diagnostic behavioural traits, and diverging into variation within the behaviourally defined phenotype (Belmonte et al, 2004). These putative causal mechanisms of social motivation and social cognition must not, be approached as exclusive of each other—or of other, even more fundamental causal mechanisms

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