Friday, May 21, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
11:00 AM
L. K. MacNeil
,
Laboratory for Neurocognitive and Imaging Research, Kennedy Krieger Institute, Baltimore, MD
L. R. Dowell
,
Laboratory for Neurocognitive and Imaging Research, Kennedy Krieger Institute, Baltimore, MD
E. M. Mahone
,
Developmental Cognitive Neurology, Kennedy Krieger Institute, Baltimore, MD
M. B. Denckla
,
Developmental Cognitive Neurology, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD
S. H. Mostofsky
,
Laboratory for Neurocognitive and Imaging Research (KKI), Departments of Neurology and Psychiatry (JHU), Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD
Background:
Motor impairment is a common finding in children with autism spectrum disorder (ASD). Studies are highly consistent in revealing that children with ASD show difficulties with motor control as well as impaired performance of more complex skilled motor gestures to command, with imitation, and with tool use on praxis examination (Dewey et al., 2007; Dowell et al., 2009; Dziuk et al., 2007; Mostofsky et al., 2006). Additionally, children with Attention-deficit/Hyperactivity Disorder (ADHD) have been shown to exhibit deficits in motor control (Cole et al., 2008; Denckla et al., 1978); however, they do not appear to show impaired praxis (Dewey et al., 2007). Objectives: To explore the specificity of impaired praxis and postural knowledge (the ability to recognize correct praxis gestures in others) to autism by examining three samples of children, including those with ASD, ADHD, and typically developing (TD) children. Methods: Twenty-four children with ASD (mean year 9.69; 5 female), 24 children with ADHD (mean year 9.73; 5 female), and 24 TD children (mean year 10.33; 5 female) each completed the Physical and Neurological Exam for Subtle Signs (PANESS) (Denckla et al., 1985) as an assessment of motor skills, a modified version of the Florida Apraxia Battery (Heilman and Rothi, 1993) as an assessment of performance of skilled gestures involving tool use (e.g., combing hair) and social communication (e.g., waving goodbye), and the Postural Knowledge Test (PKT) (Mozaz et al., 2007) as an assessment of recognition of correct hand postures necessary to perform these skilled gestures. Results: A 3-way MANOVA revealed a significant multivariate effect of diagnosis for the three motor assessments which was also observed with univariate tests for each of the three motor variables (all with p<0.01). Post hoc analyses revealed that children with ASD performed significantly worse than TD children on all three motor assessments (praxis total % correct: F=31.40, p<0.001; total PANESS: F=31.60, p<0.001; PKT: F=9.28, p=0.012). In contrast, children with ADHD performed significantly worse than TD controls on PANESS (total: F=24.64, p<0.001) but not on praxis (total % correct: F=4.84, p=0.10) or PKT. Furthermore, comparisons of ASD and ADHD groups revealed that the ASD group performed significantly worse than the ADHD group on the praxis examination (total % correct: F=13.65, p=0.003) and PKT (F=6.21, p=0.048) but not on the PANESS. All p-values were Bonferroni corrected. Conclusions: When compared to TD children, children with ASD show impaired motor control and praxis performance, as well as impaired postural knowledge; furthermore they exhibited impairments in praxis and PKT when compared to children with ADHD. In contrast, children with ADHD show impaired motor control, yet intact praxis performance and postural knowledge compared to TD children. The findings suggest that impaired formation of perceptual-motor action models necessary to development of skilled gestures and other goal directed behavior is specific to autism; whereas, impaired basic motor control may be a more generalized finding.
