Several recent studies comparing children with autism and children with other developmental disorders have concluded that the prototypical developmental profile for children with autism is one of motor skills that are relatively more advanced than social skills, even when all are delayed (DeMyer et al., 1972; Klin et al., 1992; Stone et al., 1999). Early hand-eye coordination significantly predicted later vocational skills and independent functioning, while earlier fine motor skills predicted later leisure skills (Martos-Perez and Fortea-Sevilla, 1993).
Although the basic motor skills of children with autism are often reported to be an area of relative strength, numerous studies also provide evidence that motor problems may sometimes be quite significant. Specific deficits have been reported, including in motor imitation, balance, coordination, finger-to-thumb opposition, speech articulation, and the presence of hypotonia. No significant differences were found in tactile perception or gait, beyond that accounted for by cognitive level (Jones and Prior, 1985; Rapin, 1996b; Stone et al., 1990).
Imitation skills have been a focus of study in autism. They have been consistently found to be impaired in children with autism, and deficits in imitation were found in more than 60 percent of a large longitudinal cohort (Rapin, 1996b). Imitation of body movements was more impaired than object imitation skills in young children with autism; imitation of body movements predicted later expressive language skills, and imitation of actions with objects was associated with later play skills (Stone et al., 1997). Specific gesture imitation was deficient in children with autistic spectrum disorders, although it did not account for all of the motor coordination deficits. Vocabulary size and accuracy of sign language in autistic children correlated highly with their performance on two measures of apraxia and with their fine motor age scores (Seal and Bonvillian, 1997). In addition, praxis deficits may also be present in children with autism during goal-directed motor tasks that do not require imitation (Hughes and Russel, 1993; Smith and Bryson, 1998). Deficits in oral-motor praxis, including poor range of movements, isolation of movement, and awkward execution, were also noted in children with autism given both verbal and imitative prompts (Adams, 1998; Rapin, 1996b)
Adolescents with Asperger’s Disorder and high-functioning autism showed average to above average performance in simple motor tasks, but had impairments in skilled motor tasks (Minshew et al., 1997). Both groups showed similar problems with coordination (Ghaziuddin et al., 1994). the performance of children with autism on goal-directed motor tasks was better in purposeful contexts than in nonpurposeful conditions (Hughes and Russel, 1993; Rogers et al., 1996; Stone et al., 1997).