12 Dec New Defintion of Dyslexia 2025
The International Dyslexia Association (IDA) has released its 2025 Dyslexia Definition—the first revision since its widely recognized 2002 definition.
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.” (International Dyslexia Association, 2025)
In my opinion the new definition also means that the visual orthographic component of reading is so important. That means we eventually memorize the appearance of a word and can recognize it fully in the future. We attach sound and syllable and eventually memorize whole words, so that we recognize them in a glance. Dyslexics have a diminished ability to do this. That’s why they have trouble in word reading.
Also important in the new definition is the fact that dyslexia varies on a spectrum and although early intervention is the best, long-term outcomes are not assured . Early language delays are often predictive of Dyslexia. That is why so many times a speech issue precipitates a learning disability..
The phrase “combinations of” is used to underscore the research showing that there is no single cause of dyslexia and denote that it is multifactorial in nature. Hundreds of genes have now been associated with individual differences in reading and related processes. These genes interact in complex, reciprocal ways to influence brain morphology/connectivity, but neither genes or brain differences can be used to diagnose dyslexia, serve as reliable markers for the condition, or to determine an at-risk status. (IDA, 10/28/25)The new definition is consistent with research that indicates reading and spelling difficulties are not categorical in nature, that is, show a clear division between good and poor reading/spelling. Rather literacy abilities, like many abilities, fall along a continuum of skill from good to poor with most individuals in the average range. (IDA, 10/28/25)