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IDA 2025 Definition of Dyslexia
IDA 2025 Definition of Dyslexia
“Dyslexia is a specific learning disability characterized by difficulties in word reading and/or spelling that involve accuracy, speed, or both and vary depending on the orthography. These difficulties occur along a continuum of severity and persist even with instruction that is effective for the individual’s peers. The causes of dyslexia are complex and involve combinations of genetic, neurobiological, and environmental influences that interact throughout development. Underlying difficulties with phonological and morphological processing are common but not universal, and early oral language weaknesses often foreshadow literacy challenges. Secondary consequences include reading comprehension problems and reduced reading and writing experience that can impede growth in language, knowledge, written expression, and overall academic achievement. Psychological well-being and employment opportunities also may be affected. Although identification and targeted instruction are important at any age, language and literacy support before and during the early years of education is particularly effective.”
The International Dyslexia Association (IDA) is pleased to share the 2025 Dyslexia Definition, developed through a rigorous, collaborative process to reflect the latest research and the lived experiences of individuals with dyslexia. To explore the definition in greater depth, including the scientific and community-based foundations that informed its development, visit the 2025 IDA Definition Explanation below and view the IDA Definition Presentation.
Dyslexia Characteristics
Students identified as having dyslexia typically experience primary difficulties in phonological awareness, including phonemic awareness and manipulation, single-word reading, reading fluency, and spelling. Consequences may include difficulties in reading comprehension and/or written expression. These difficulties in phonological awareness are unexpected for the student’s age and educational level and are not primarily the result of language difference factors. Additionally, there is often a family history of similar difficulties.
The following are the primary reading/spelling characteristics of dyslexia:
• Difficulty reading words in isolation
• Difficulty accurately decoding unfamiliar words
• Difficulty with oral reading (slow, inaccurate, or labored without prosody)
• Difficulty spelling
It is important to note that individuals demonstrate differences in degree of impairment and may not exhibit all the characteristics listed above.
The reading/spelling characteristics are most often associated with the following: • Segmenting, blending, and manipulating sounds in words (phonemic awareness) • Learning the names of letters and their associated sounds
• Holding information about sounds and words in memory (phonologicalmemory) • Rapidly recalling the names of familiar objects, colors, or letters of the alphabet (rapid naming)
Consequences of dyslexia may include the following:
• Variable difficulty with aspects of reading comprehension
• Variable difficulty with aspects of written language
• Limited vocabulary growth due to reduced reading experiences
Sources for Characteristics and Consequences of Dyslexia
Branum-Martin, L., Fletcher, J. M., & Stuebing, K. K. (2013). Classification and identification of reading and math disabilities: The special case of comorbidity. Journal of Learning Disabilities, 12, 906–915.
Fletcher, J. M., Lyon, G. R., Fuchs, L. S., & Barnes, M. A. (2007). Learning disabilities: From identification to intervention. New York, NY: The Guilford Press.
The International Dyslexia Association. (2018). Knowledge and practice standards for teachers of reading, (2nd ed.). Retrieved from https://app.box.com/s/21gdk2k1p3bnagdfz1xy0v98j5ytl1w. Moats, L. C., & Dakin, K. E. (2008).
Basic facts about dyslexia and other reading problems. Baltimore, MD: The International Dyslexia Association.
HCISD Dyslexia Program Procedures Manual
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