Definitions and Characteristics of Dyslexia

Texas Education Code (TEC) §38.003 defines dyslexia in the following way: 

1. "Dyslexia" means a disorder of constitutional origin manifested by difficulty in learning to read, write, or spell, despite conventional instruction, adequate intelligence, and sociocultural opportunity. (TEC Section 38.003)
2. “Related disorders” include disorders similar to or related to dyslexia such as auditory imperception, dysphasia, specific developmental dyslexia, development dysgraphia, and developmental spelling disability.  

The International Dyslexia Association defines “dyslexia” in the following way:

Dyslexia is a specific learning disability that is neurological in origin.  It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.

 --Adopted by the IDA Board of Directors, Nov. 12, 2002. This Definition is also used by the National Institute of Child Health and Human Development (NICHD).

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)
• Difficulty spelling

 It is important to note that individuals demonstrate differences in degree of impairment.

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 (phonological memory)
• 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