At the recent IDA National Reading, Literacy, and Learning Conference, DyslexiaCon in Atlanta, Georgia, a dedicated symposium explored the historical context and multi-phase process of revising the definition of dyslexia. This new definition is global in scope, encompassing all orthographies—including those of populations whose writing systems are not alphabetic, such as English.

As Hugh Catts shared, “…one constant is that this and future definitions reflect the best that science has to offer.”

Learn more about the 2025 Dyslexia Definition Project here: IDA Dyslexia Definition Project

Key takeaways from the discussion:

• • Dyslexia is a complex condition with no singular cause. It reflects an interplay of neurobiological, genetic, and environmental influences. Dyslexia cannot be diagnosed by brain scans, many individuals with dyslexia have no family history of reading difficulties.
  • “Environmental influences” refer primarily to the learning environment and how it interacts with neurological and genetic factors, shaping both risk and resilience.
  • Highlights the value of targeted instruction and the critical importance of early detection and intervention.
  • The importance of early detection and intervention cannot be overstated. Dyslexia is real, and the definition clarifies that it does not assign blame to parents.
  • Consequences broadened to better reflect the implications and lived experiences of dyslexia. Dyslexia can have significant effects on emotional well-being.
  • A Glossary of Terms will accompany the new definition, providing clarity for educators, clinicians, and families.

The 2002 definition was considered a “working definition.” Over the past 23 years, research and practice have significantly advanced our understanding. The new definition, like its predecessors, is evidence-informed and designed to evolve.

During the conference, a discussion highlighted the work of researchers in Canada, including Dr. Jamie Metsala (MSVU, Halifax) and Dr. Linda Siegel (UBC, British Columbia), who critiqued the 2002 definition and emphasized the need for revision based on current research. You can read Thoughts on the Definition of Dyslexia from Linda S. Siegel, David P. Hurford, Jamie L. Metsala, Michaela R. Ozier & Alex C. Fender here.