Co-Principal Investigator: Lisa Daunhauer

Purpose: Down Syndrome (DS) is the most common genetic cause of intellectual disability. In addition to other documented cognitive problems, preliminary evidence suggests that children with DS may have deficits in certain executive functioning (EF) skills—cognitive processes that are important for adaptive, goal-directed actions. The potential EF deficits in children with DS may have critical educational implications. In typically developing children, EF skills are associated with early school performance. Further, there is preliminary evidence that the impairments in children with DS may be in those particular EF skills (e.g., working memory) that are stronger predictors of achievement and learning than other EF skills.

This research will characterize the profile of relative strengths and weaknesses in EF skills in children with DS compared to children with other intellectual disabilities and typically developing children. More specifically, the research will examine whether "cool" EF skills (i.e., those with primarily cognitive demands, including working memory and planning) are more impaired in children with DS than "hot" EF skill (i.e., those that incorporate affect and motivation, including inhibition and set shifting). Further, the study will investigate how EF skills are associated with academic and related skills in each group of children, how EF skills in kindergarten relate to academic skills in second grade, and whether there are group differences in the development of EF skills over time.

Project Activities: This research team will investigate EF skills in children with DS by collecting data from students, parents, and teachers when students are in kindergarten and second grade. During a visit to the university, students will be administered the battery of tasks measuring EF, cognitive ability, language, and achievement during their kindergarten year. At that time, parents will complete a questionnaire about the student and family background. During this first wave of data collection, teachers will be mailed a battery of questionnaires to measure student EF, behavior, and adaptive functioning in the classroom. The second wave of data collection will take place when each of these children are in second grade. At this time, the same battery of assessments will be administered to the children, and the questionnaires will be completed by parents and teachers.

Products: Products from this study will be published reports and presentations on the comparison of children with DS to those with mixed intellectual disabilities and typically developing children on EF skills. These finding will include the profile of relative strengths and weaknesses in EF skills, how these EF skills relate to academic performance concurrently and over time, and the magnitudes of change in EF skills over time. The knowledge gained from this project will create a foundation for developing an EF intervention designed specifically for young students with DS.

Setting: Assessments for children and parents will take place at Colorado State University, with questionnaires mailed to teachers.

Population: Ninety students will begin participating in their kindergarten year. Of these students, 30 will be children with DS, 30 will be children with idiopathic intellectual delay (intellectual disability without diagnosis of a specific syndrome), and 30 will be typically developing children. For the DS group, children will have a previous genetic diagnosis of Trisomy 21. The intellectual disabilities group will be matched on chronological age, as well as scores on cognitive ability and receptive language. In each of these groups, the child must have no other medical impairments beyond those typically associated with their disability, an overall developmental level (nonverbal mental age) of at least 24 months, and no diagnosis of autism. The typically developing children will be matched with the other two groups on cognitive ability (mental age). The students' parents and teachers with whom the students spend the most time will also participate.

Intervention: Not applicable.

Research Design and Methods: This project is a longitudinal, three-group design to compare children with DS with two control conditions (intellectual disabilities and typically developing). Direct assessments of the children on EF, cognitive ability, language, and achievement will be collected in two waves of data collection—kindergarten and second grade. Teacher questionnaires on student classroom performance will be collected via mailings in both waves, and parents will complete a child and family background questionnaire.

Control Condition: Two control groups will include: (1) children with idiopathic developmental delays (intellectual disability without diagnosis of a specific syndrome) matched on chronological and mental age; and (2) typically developing children matched on mental age.

Key Measures: Executive functioning will be measured with a battery of instruments, based on previously developed tasks, administered directly to the child. These tasks measure different domains of EF: working memory (e.g., ability to remember to follow instructions from the bear but not the dragon), inhibition (e.g., ability to delay retrieval of a desired snack or gift), set shifting or cognitive flexibility (e.g., ability to adapt to a switch in instructions such as changing the category on which to sort cards), and planning (e.g., ability to generate novel behaviors used with a toy). Cognitive ability (nonverbal mental age) will be measured with visual reasoning subtests of the Leiter International Performance Scale-Revised, receptive language with the Peabody Picture Vocabulary Test-IV, and academic achievement with subtests from the Woodcock-Johnson Test of Achievement Battery–III. Teachers will complete a battery of established questionnaires that assess the child's classroom executive functioning, behavior, and adaptive skills (e.g., Vineland Adaptive Behavior Scales). Parents will complete a questionnaire to measure student and family characteristics (e.g., genetic testing, interventions, family economic status).

Data Analytic Strategy: After composite scores are created for each EF domain (working memory, planning, set shifting, and inhibition), the investigators will use multivariate analysis of variance at each time point to determine whether there are differences among the groups in domain performance. Using regression, the data will be examined for the relationship between EF skills and academic skills in each group at each time point, the association between EF skills at time 1 and academic skills at time 2 for each group, and group differences in the magnitude of change over time in EF skills.

Products and Publications

Book chapter

Daunhauer, L.A. and Fidler, D.J. (2013). Self-Regulation in Atypical Development: An Overview of the Section. In K.C. Barrett, and G. Morgan (Eds.), Handbook of Self-Regulatory Processes in Development: New Directions and International Perspectives (pp. 405–408). New York: Psychology Press.

Daunhauer, L.A., and Fidler, D.J. (2013). Executive Functioning in Individuals With Down Syndrome. In K.C. Barrett, and G.A. Morgan (Eds.), The Handbook of Self-Regulatory Processes in Development: New Directions and International Perspectives (pp. 453–474). New York: Psychology Press.

Daunhauer, L.A., and Fidler, D.J. (in press). Self Regulation in Down Syndrome. In K. C. Barrett, and G. Morgan (Eds.), The Handbook of Self-Regulatory Processes.

Fidler, D.J., and Daunhauer, L.A. (2012). Growth in Individuals With Down Syndrome. In V.R. Preedy (Ed.), Handbook of Growth and Growth Monitoring in Health and Disease, Vol 3 (pp. 2231–2245). London: Springer.

Fidler, D.J., Daunhauer, L.A., Will, E., Gerlach-McDonald, B., and Schworer, E. (in press). The Central Role of Etiology in Science and Service in Intellectual Disability. International Review of Research in Developmental Disabilities.

Fidler, D.J., Hepburn, S.L., and Osaki, D. (2011). Goal-Directedness as a Target for Early Intervention in Down Syndrome. In J. Rondal, and J. Perera (Eds.), Neurocognitive Rehabilitation in Down Syndrome: The Early Years. Portland, OR: Book News, Inc.

Will, E., Fidler, D.J., and Daunhauer, L.A. (2014). Executive Function and Planning in Early Development in Down Syndrome. International Review of Research in Developmental Disabilities, Volume 47 (pp. 77–98). Waltham, MA: Elsevier, Inc. doi:10.1016/B978–0–12–800278–0.00003–8

Book chapter, edition specified

Daunhauer, L.A., Gerlach-McDonald, B., and Khetani, M.A. (2014). Rules of "Engagement": Addressing Participation and Functional Performance in Children With Intellectual and Developmental Disabilities. In R. Hodapp (Ed.), International Review of Research in Developmental Disabilities, Volume 47 (1st ed., pp. 151–184). Waltham, MA: Elsevier, Inc. doi:10.1016/B978–0–12–800278–0.00005–1

Journal article, monograph, or newsletter

Daunhauer, L.A, and Fidler, D.J. (2011). The Down Syndrome Behavioral Phenotype: Implications for Practice and Research in Occupational Therapy. Occupational Therapy in Health Care, 25(1): 7–25. doi:10.3109/07380577.2010.535601

Daunhauer, L.A. (2011). The Early Development of Adaptive Behavior and Functional Abilities in Young Children With Down Syndrome: Current Knowledge and Future Directions. International Review of Research in Developmental Disabilities, 40: 109–137. doi:10.1016/B978–0–12–374478–4.00005–8

Daunhauer, L.A., Fidler, D.J., and Will, E. (2014). School Function in Students With Down Syndrome. American Journal of Occupational Therapy, 68(2): 167–176. doi:10.5014/ajot.2014.009274

Daunhauer, L.A., Fidler, D.J., Hahn, L.J., Will, E., Lee, N.R., and Hepburn, S.L. (2014). Profiles of Everyday Executive Functioning in Young Children With Down Syndrome. American Journal on Intellectual and Developmental Disabilities, 119(4): 303–318. doi:10.1352/1944–7558–119.4.303

Fidler, D.J., Lunkenheimer, E.S., and Hahn, L.J. (2011). Emerging Behavioral Phenotypes and Dynamic Systems Theory. International Review of Research in Developmental Disabilities, 40: 17–42. doi:10.1016/B978–0–12–374478–4.00002–2

Fidler, D.J., Will, E., Daunhauer, L.A., Gerlach-McDonald, B., and Visootsak, J. (2014). Object-Related Generativity in Children With Down Syndrome. Research in Developmental Disabilities, 35(12): 3379–3385. doi:10.1016/j.ridd.2014.07.024

Hahn, L.J., Fidler, D.J., Hepburn, S.L., and Rogers, S.J. (2013). Early Intersubjective Skills and the Understanding of Intentionality in Young Children With Down Syndrome. Research in Developmental Disabilities, 34(12): 4455–4465. doi:10.1016/j.ridd.2013.09.027

Hodapp, R.M., Fidler, D.J., and Depta, E. (in press). Blurring Boundaries, Continuing Change: The Next 50 Years of Research in Intellectual and Developmental Disabilities. International Review of Research in Developmental Disabilities. doi:10.1016/bs.irrdd.2016.05.001

Lee, N.R., Anand, P., Will, E., Adeyemi, E.I., Clasen, L.S., Giedd, J.N., Daunhauer, L., Fidler, D.J., and Edgin, J. (2015). Everyday Executive Functions in Down syndrome From Early Childhood to Young Adulthood: Evidence for Both Unique and Shared Characteristics Compared to Youth With Sex Chromosome Trisomy (XXX and XXY). Frontiers in Neuroscience, 9: 264. doi:10.3389/fnbeh.2015.00264