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Early Gross and Fine Motor Abilities in Infants at Heightened Vs. Low Risk for ASD: A Bsrc Study

Thursday, May 14, 2015: 5:30 PM-7:00 PM
Imperial Ballroom (Grand America Hotel)
J. M. Iverson1, F. Shic2, C. A. Wall3, Y. Bensinger-Brody4, S. Curtin5, A. M. Estes6, J. M. Gardner7, T. Hutman8, S. Johnson9, B. Z. Karmel7, R. J. Landa10, A. R. Levin11, K. Libertus1, D. S. Messinger12, C. A. Nelson13, S. Ozonoff14, J. Piven15, S. J. Rogers16, L. A. Sacrey17, K. Sheperd18, W. L. Stone19, H. Tager-Flusberg20, J. J. Wolff21, N. Yirmiya22 and G. S. Young23, (1)University of Pittsburgh, Pittsburgh, PA, (2)Yale Child Study Center, Yale University School of Medicine, New Haven, CT, (3)Yale University, New Haven, CT, (4)Physical Therapy, Touro College, Bay Shore, NY, (5)University of Calgary, Calgary, AB, Canada, (6)Speech and Hearing Sciences, University of Washington, Seattle, WA, (7)Infant Development, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, (8)Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, CA, (9)University of California Los Angeles, Los Angeles, CA, (10)Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, (11)Neurology, Boston Children's Hospital, Boston, MA, (12)University of Miami, Coral Gables, FL, (13)Division of Developmental Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, (14)MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis Medical Center, Sacramento, CA, (15)*Shared Senior Author, ., NC, (16)University of California at Davis, Sacramento, CA, (17)University of Alberta, Edmonton, AB, Canada, (18)Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD, (19)Psychology, University of Washington, Seattle, WA, (20)Boston University, Boston, MA, (21)Department of Educational Psychology, University of Minnesota, Minneapolis, MN, (22)Psychology Department, Hebrew University, Jerusalem, Israel, (23)MIND Institute, University California Davis, Sacramento, CA
Background:  A growing body of research has pointed to the presence of early-appearing delays in gross motor (GM) and fine motor (FM) development in infants at heightened risk (HR) for ASD (e.g., Libertus et al., 2014; Nickel et al., 2013). In addition, relative to HR infants who are not later diagnosed with ASD and to infants with low ASD risk (LR), HR infants later diagnosed with ASD exhibit poorer gross and fine motor skills by 6 months of age (e.g., Leonard et al., 2013). However, much of this work has involved comparison of overall scores on standardized assessments and relatively small sample sizes.

Objectives:  To examine GM and FM skills at an item level at 6 months in relation to outcome classification at 36 months in a large sample of HR and LR infants.

Methods:  This study utilized data from the GM and FM subscales of the Mullen Scales of Early Learning (MSEL) administered at 6 months of age at 7 Baby Siblings Research Consortium (BSRC) sites. The total sample included 530 infants (363 HR, 167 LR). Thirty-six month outcome classification followed procedures outlined by Chawarska et al. (2014), with HR infants categorized as ASD, Atypically-Developing (ATYP), or Typically-Developing (HR-TD). A comparison sample of typically-developing low risk infants (LR-TD) was also included.

Results:  

General linear mixed model logistic regressions with outcome classification and item as fixed effects and random intercepts for participants were carried out separately on the GM and FM subscale data (Figure 1). Results were generally similar across subscales, with group item performance for GM: (ASD=ATYP)<LR-TD (p<.01) and (ASD=ATYP)<HR-TD(p~.06); and for FM (ASD=ATYP)<LR-TD (p<.05,.01) and HR-TD<LR-TD (p<.01).

To examine motor milestones specific to age 6 months, we focused on subsets of 4 items on each subscale tapping sitting and grasping skills respectively and identified infants who were low performers (≥3 items failed; Figure 2).

For sitting items, significantly more ASD and ATYP infants were low performers relative to both the HR-TD and LR-TD groups, who did not differ from one another. A similar pattern of differences was evident for grasping items, but in addition, significantly more HR-TD infants fell into the low performing group relative to the LR-TD group (all ps < .05). Within the ASD group, significantly more females (44%) than males (22%) failed 3 or more grasping items (p = .04).

Conclusions:  Delays in gross and fine motor development were evident among ASD infants at 6 months of age, but similar delays were also apparent among HR-ATYP infants. In addition, HR-TD infants also demonstrated delays relative to LR-TD infants in fine motor skills. These findings have implications for early identification and intervention efforts and for the

understanding of the pathways from genetic risk for ASD to social and cognitive impairments associated with ASD and the broader autism phenotype.