title: Williams syndrome: a surprising deficit in oromotor praxis in a population with proficient language production.
abstract: Williams Syndrome (WS) is a neurodevelopmental disorder of known genetic origin, characterized by serious delays in language onset yet relatively verbose, intelligible and fluent speech in late childhood and adulthood. How do motor abilities relate to language in this group? We investigated planning and co-ordination of the movement of the speech articulators (oromotor praxis) in 28 fluent-speaking individuals with WS, aged between 12 and 30 years. Results indicate that, despite their fluent language, oromotor praxis was impaired in WS relative to two groups of typically-developing children, matched on either vocabulary or visuospatial ability. These findings suggest that the ability to plan, co-ordinate and execute complex sensorimotor movements contribute to an explanation of the delay in expressive language early in development in this neurodevelopmental disorder. In the discussion, we turn to more general issues of how individual variation in oromotor praxis may account for differences in speech/language production abilities across developmental language disorders.
authors.affiliation: Centre for Brain and Cognitive Development, Department of Psychological Sciences, Birkbeck, University of London, UK; Institute of Cognitive Neuroscience, UCL, UK. Electronic address: s.krishnan@ucl.ac.uk.
authors.forename: Saloni
authors.initials: S
authors.lastname: Krishnan
authors.affiliation: Centre for Brain and Cognitive Development, Department of Psychological Sciences, Birkbeck, University of London, UK.
authors.forename: Lina
authors.initials: L
authors.lastname: Bergström
authors.affiliation: Department of Psychology, Lancaster University, UK.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Alcock
authors.affiliation: Centre for Brain and Cognitive Development, Department of Psychological Sciences, Birkbeck, University of London, UK.
authors.forename: Frederic
authors.initials: F
authors.lastname: Dick
authors.affiliation: Centre for Brain and Cognitive Development, Department of Psychological Sciences, Birkbeck, University of London, UK.
authors.forename: Annette
authors.initials: A
authors.lastname: Karmiloff-Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D007805:Language Development Disorders / Q000503:physiopathology*; D007807:Language Tests; D008297:Male; D013060:Speech / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology*; D018980:Williams Syndrome / Q000503:physiopathology*; D055815:Young Adult
keywords: Motor ability; Orofacial movements; Sequencing; Speech motor control; Williams syndrome