The research of Leonard Abbeduto, Ph.D. is focused broadly on the development of language across the lifespan in individuals with intellectual and developmental disabilities and on the family context for language development. He has published more than 240 articles, chapters, reviews, and books on fragile X syndrome, autism, Down syndrome, and child development. His program of research has been funded nearly continuously by NIH since 1985. His current research is focused on understanding variation in language outcomes in various conditions associated with intellectual disability, the measurement of treatment effects in clinical trials, and the use of distance technology to deliver behavioral treatment. He serves as a Principal Investigator and Co-director of the NICHD-funded MIND Institute Intellectual and Developmental Disabilities Research Center (IDDRC), which provides core support to more than 80 projects and 40 scientists at the MIND Institute. He also co-directs the UC Davis Redwood SEED Scholars program, which is a 4-year, residential, inclusive college program for individuals with intellectual disabilities. He has received numerous awards, including the Emil H. Steiger Award for Distinguished Teaching from the University of Wisconsin-Madison, the Faculty Stewardship Award from the University of California, Davis, the Enid and William Rosen Research Award from the National Fragile X Foundation, and the Edgard Doll Award for Distinguished Research Contribution from Division 33 of the American Psychological Association. 

Select Publications

Abbeduto, L., del Hoyo Soriano, L., Berry-Kravis. E., Sterling, A., Edgin4, J.O., Abdelnur, N., Drayton, A., Hoffmann, A., Hamilton\, D., Harvey, D.J., & Thurman, A.J. (2023). Expressive language sampling and outcome measures for treatment trials in fragile X and Down syndromes: Composite scores and psychometric properties. Scientific Reports, 13, 9267. https://doi.org/10.1038/s41598-023-36087-3

del Hoyo Soriano, L., Villarreal, J., & Abbeduto, L. (2023). Parental survey on Spanish-English bilingualism in neurotypical development and neurodevelopmental disabilities in the United States. Advances in Neurodevelopmental Disorders.

del Hoyo Soriano, L., Sterling, A., Edgin, J., Hamilton, D.R., Berry-Kravis, E., Dimachkie Nunnally, A., Thurman, A.J., & Abbeduto, L. (2023). Associations among sex, cognitive ability, and autism symptoms in individuals with Down syndrome. Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s10803-022-05779-6

Dimachkie Nunnally A, Factor RS, Sturm A, Valluripalli Soorya L, Wainer A, Taylor S, Ponzini M, Abbeduto L and Gulsrud AC (2023). Examining indicators of psychosocial risk and resilience in parents of autistic children. Front. Behav. Neurosci. 17:1102516. https://doi.org/10.3389/fnbeh.2023.1102516

Frazier, T. W., Dimitropoulos, A., Abbeduto, L., Armstrong-Brine, M., Kralovic, S., Shih, A., Hardan, A. Y., Youngstrom, E. A., Uljarevic, M., & Quadrant Biosciences - As You Are, T. (2023). The Autism Symptom Dimensions Questionnaire: Development and psychometric evaluation of a new, open-source measure of autism symptomatology. Developmental Medicine and Child Neurology. https://doi.org/10.1111/dmcn.15497 

MacFarlane, H., Salem, A.C., Bedrick, S., Dolata, J.K., Wiedrick, J., Lawley, G.O., Finestack, L.H., Kover, S.T., Thurman, A.J., Abbeduto, L., & Fombonne, E. (2023). Consistency and reliability of automated language measures across expressive language samples in autism. Autism Research, 2023 Feb 1. doi: 10.1002/aur.2897.

Pinks, M. E., Van Deusen, K., Prince, M. A., Esbensen, A. J., Thurman, A. John, Patel, L. R., Abbeduto, L., Walsh, M., Daunhauer, L. A., Feigles, R. T., Nguyen, V., & Fidler, D. J. (2023). Psychometric evaluation of a working memory assessment measure in young children with Down syndrome. Research in Developmental Disabilities, 139.  https://doi.org/10.1016/j.ridd.2023.104564

Ramkumar, A., Chi, M-H, Zafarullah, M., Mendoza, G., Ponzini, M.D., Kim, K., Biag, H.M.B., Thurman, A.J., Abbeduto, L.J., Hessl, D., Randol, J.L., Bolduc, F.V., Jacquemont, S., Lippe, S., Hagerman, P., Hagerman, R., Schneider, A., & Tassone, F. (2023). Intercorrelation of molecular biomarkers and clinical phenotype measures in Fragile X Syndrome. Cells.

Van Deusen, K., Prince, M. A., Thurman, A. J., Esbensen, A. J., Patel, L. R., Abbeduto, L. et al. (2023). Evaluating an adapted reverse categorisation task to assess cognitive flexibility in young children with Down syndrome. Journal of Intellectual Disability Research. https://doi.org/10.1111/jir.13040

Klusek, J., Will, E., Moser, C., Hills, K., Thurman, A.J., Abbeduto L, & Roberts, J.E. (2023). Predictors, parental views, and concordance across diagnostic sources of autism in male youth with fragile X syndrome: Clinical best estimate and community diagnoses. Research in Child and Adolescent Psychopathology, Mar 3. https://doi.org/10.1007/s10802-023-01059-8

del Hoyo Soriano, L. Villarreal, J.C., Sterling, A., Edgin, J., Berry-Kravis, E., Hamilton, D.R., Thurman, A.J., & Abbeduto, L. (2022). The association between expressive language skills and adaptive behavior in individuals with Down syndrome. Scientific Reports, 12(1):20014. https://doi.org/10.1038/s41598-022-24478-x

Potter, S.N., Harvey, D.J., Sterling, A., & Abbeduto, L. (2022). Mental health challenges, parenting stress, and features of the couple relationship in parents of children with fragile X syndrome. Frontiers in Psychiatry, 01 April 2022 | https://doi.org/10.3389/fpsyt.2022.857633

Bullard, L., Harvey, D., & Abbeduto, L. (2021). Exploring the feasibility of collecting multimodal multiperson assessment data via distance in families affected by fragile X syndrome. Journal of Telemedicine and Telecare. 2021 Apr 12;1357633X211003810. https://doi.org/10.1177/1357633X211003810 .

Klusek, J., Thurman, A.J., & Abbeduto, L. (2021). Maternal pragmatic language difficulties in the fmr1 premutation and the broad autism phenotype: Associations with individual and family outcomes. Journal of Autism and Developmental Disorders. 2021 Apr 4. https://doi.org/10.1007/s10803-021-04980-3. Online ahead of print.

Thurman, A.J., Edgin, J.O., Sherman, S., Sterling, A., McDuffie, A., Hamilton, D., & Abbeduto, L. (2021). Spoken language outcome measures for treatment studies in Down syndrome: feasibility, practice effects, test-retest reliability, and construct validity of variables generated from expressive language sampling. Journal of Neurodevelopmental Disorders. 2021 Apr 8;13(1):13. https://doi.org/10.1186/s11689-021-09361-6.

Abbeduto, L., Thurman, A.J., McDuffie, A., Klusek, J., Tempero Feigles, R., Brown, W.T., Harvey, D., Adayev, T., LaFauci, G., Dobkins, C., & Roberts, J.E. (2019). ASD Comorbidity in Fragile X Syndrome: Symptom Profile and Predictors of Symptom Severity in Adolescent and Young Adult Males. Journal of Autism and Developmental Disorders, 49, 960-977.

Conners, F.A., Tungate, A.S., Abbeduto, L., Merrill, E.C., & Faught, G.G. (2018). Growth and decline in language and phonological memory over two years among adolescents with Down syndrome. American Journal on Intellectual and Developmental Disabilities, 123, 103-118.

del Hoyo Soriano, L., Thurman, A.J., Harvey, D.J., Brown, W.T., Abbeduto, L. (2018). Genetic and maternal predictors of cognitive and behavioral trajectories in females with fragile X syndrome. Journal of Neurodevelopmental Disorders, 10:22.

Ezell, J., Hogan, A., Fairchild, A., Hills, K., Klusek, J., Abbeduto, L., & Roberts, J. (2018). Prevalence and Predictors of Anxiety Disorders in Adolescent and Adult Males with Autism Spectrum Disorder and Fragile X Syndrome. Journal of Autism and Developmental Disorders. doi: 10.1007/s10803-018-3804-6.

Klusek, J., Porter, A., Abbeduto, L., Adayev, T., Tassone, F., Mailick, M., Glicksman, A., Tonnsen, B., Roberts, J.E. (2018). Curvilinear Association between Language Disfluency and FMR1 CGG Repeat Size across the Normal, Intermediate, and Premutation Range. Frontiers in Genetics.

Matherly, S.M., Klusek, J., Thurman, A.J., McDuffie, A., Abbeduto, L., & Roberts, J.E. (2018). Cortisol profiles differentiated in adolescents and young adult males with fragile X syndrome versus autism spectrum disorder. Developmental Psychobiology, 60, 78-89.

McDuffie, A., Banasik, A., Bullard, L., Nelson, S., Tempero Feigles, R., Hagerman, R.J., Abbeduto, L. (2018). Distance delivery of a spoken language intervention for school-aged and adolescent boys with fragile X syndrome. Developmental Neurorehabilitation, 21, 48-63.

Nelson, S., McDuffie, A., Banasik, A., Tempero Feigles, R., Thurman, A.J., & Abbeduto, L. (2018). Inferential language use by school-aged boys with fragile X syndrome: Effects of a parent-implemented spoken language intervention. Journal of Communication Disorders, 72, 64-76.

Roberts, J.E., Ezell, J. Fairchild, A. Klusek, J., Thurman, A.J., McDuffie, A., & Abbeduto, L. (2018). Biobehavioral Composite of Social Aspects of Anxiety in Young Adults with Fragile X contrasted to Autism Spectrum Disorder. American Journal of Medical Genetics: Part B. Neuropsychiatric Genetics, 177, 665-675.

Select Grants

Principal Investigator, MIND Institute Intellectual and Developmental Disabilities Research Center, National Institute of Child Health and Human Development, P50HD103526, 06/1/20-5/31/2025, $6.5 million (total costs).

Principal Investigator, Creating Partnerships with Diverse and Underrepresented Communities to Build a Research Network. PCORI EASC-00269, 11/01/2021-10/31/2023, $247,393 (total costs).

Principal Investigator, SPARK Raven's Pilot and Validation. SFARI (Simons Foundation), 04/01/2023-03/31/2024. $60,000 (total costs).