The International Dyslexia Association Definition of Dyslexia

Most current definition: Dyslexia is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate/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, November 12, 2002.
• This definition is also used by the National Institutes of Child Health and Human Development (NICHD), 2002.

Let’s break it down:

Specific learning disability – research has indicated specific cognitive characteristics related to dyslexia.

…that is neurological in origin – dyslexia results from differences in how the brain processes information. Specifically, functional brain imaging has demonstrated a failure of the left hemisphere posterior brain systems to function properly during reading.

More information:

• National Center for the Study of Adult Learning & Literacy

Dyslexia is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities – students with dyslexia will demonstrate difficulties identifying real words (word recognition) and pronouncing nonsense words (decoding); the student’s ability to read fluently is also a major characteristic as well as difficulty with spelling. This is in contrast to the popularly held belief that the major characteristic is the reversal of letters, words and numbers.

These difficulties typically result from a deficit in the phonological component of language – making the connection between oral language and the letters/sounds that represent language in written form requires an awareness that all words can be decomposed into phonologic segments (i.e., the word bat can be broken down into three phonemes or individual sounds – b, a, and t). Research findings have been consistent in confirming that in young school-age children as well as in adolescents, a deficit in phonology is the strongest and most specific finding related to dyslexia.

That is often unexpected in relation to other cognitive abilities – unexpected in relation to the student’s: oral language skills, the ability to learn in the absence of print, intellectual functioning, or strong math skills in comparison to reading skills.

…and the provision of effective classroom instruction – if the child has been identified as at-risk for reading failure in kindergarten and first grade, have they been provided with effective instruction in order to develop proficient early reading skills? The lack of response to scientifically informed instruction is one factor that differentiates severe reading deficits from reading failure resulting from inadequate instruction. Early intervention is critical…students who receive appropriate instruction show changes in how their brain processes the information so that it resembles that of non disabled readers. Research has found that effective early interventions have the capability of reducing the expected incidence of reading failure from 18% of the school age population to 1 – 5%.

Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge – because students with reading difficulties typically do not read the same amount as non disabled readers, it may impact their vocabulary development as well as their exposure to information learned by reading.

[Source: A Definition of Dyslexia by G. Reid Lyon, Sally E. Shaywitz and Bennett A. Shaywitz; Annuals of Dyslexia, Volume 53, 2003]

A few quick facts about dyslexia:

• The word dyslexia comes from the Greek language and means poor language.
• Dyslexia is a life-long status, however, its impact can change at different stages in a person’s life.
• Dyslexia is not due to either lack of intelligence or a desire to learn; with appropriate teaching methods dyslexics can learn successfully.
• Early identification and treatment is the key to helping dyslexics achieve in school and in life.

(Source: The International Dyslexia Association)

Instruction for Students with Dyslexia

School districts may purchase a reading program or develop their own reading program for students with dyslexia and related disorders as long as the program is characterized by the descriptors found in The Dyslexia Handbook [19 TAC §74.28(c)].

Descriptors related to evidence-based instructional components:

• Phonological awareness – "Phonological awareness is the understanding of the internal sound structure of words. A phoneme is the smallest unit of sound in a given language that can be recognized as being distinct from other sounds. An important aspect of phonological awareness is the ability to segment spoken words into their component phonemes" (Birsh, 2011, p.19).
• Sound-symbol association – Sound-symbol association is the knowledge of the varies speech sounds in any language to the corresponding letter or letter combinations that represent those speech sounds. The mastery of sound/symbol association (alphabetic principle) is the foundation for the ability to read (decode) and spell (encode) (Birsh, 2011, p.19). "Explicit phonics refers to an organized program in which these sound symbol correspondences are taught systematically" (Berninger & Wolf, 2009, p. 53).
• Syllabication – "A syllable is a unit of oral or written language with one vowel sound. The six basic types of syllables in the English language include the following; closed, open, vowel-e consonant-e, r-controlled, vowel pair (or vowel team), and consonant-le (or final stable syllable). Rules for dividing syllables must be directly taught in relation to the word structure" (Birsh, 2011, p. 19).
• Orthography – Orthography is the written spelling patterns and rules in a given language. Students must be taught the regularity and irregularity of the orthographic patterns of a language in an explicit and systematic manner. The instruction should be integrated with phonology and sound-symbol knowledge.
• Morphology – "Morphology is the study of how a base word, prefix, root, suffix (morphemes) combine to form words. A morpheme is the smallest unit of meaning in a given Language" (Birsh, 2011, p. 19).
• Syntax – "Syntax is the sequence and function of words in a sentence in order to convey meaning. This includes grammar and sentence variation and affects choices regarding mechanics of a given language" (Birsh, 2011, p. 19).
• Reading comprehension – Reading comprehension is the process of extracting and constructing meaning through the interaction of the reader with the text to be comprehended and the specific purpose for reading. The reader's skill in reading comprehension depends upon the development of accurate and fluent word recognition, oral language development (especially vocabulary and listening comprehension), background knowledge, use of appropriate strategies to enhance comprehension and repair it if it breaks down, and the reader's interest in what he or she is reading and motivation to comprehend its meaning (Birsh, 2011, pp. 9 and 368; Snow, 2002).
• Reading fluency – "Reading fluency is the ability to read text with sufficient speed and accuracy to support comprehension" (Moats & Dakin, 2008, p. 52). Teachers can help promote fluency with several interventions that have proven successful in helping students with fluency (e.g., repeated readings, word lists, and choral reading of passages) (Henry, 2010, p. 104).

Descriptors related to instructional approaches:

• Simultaneous, multisensory (VAKT) – "Multisensory instruction utilizes all learning pathways in the brain (visual, auditory, kinesthetic-tactile) simultaneously in order to enhance memory and learning" (Birsh, 2011, p. 19). "Children are actively engaged in learning language concepts and other information, often by using their hands, arms, mouths, eyes, and whole bodies while learning" (Moats & Dakin, 2008, p. 58).
• Systematic and cumulative – "Systematic and cumulative instruction requires the organization of material follow order of the language. The sequence must begin with the easiest concepts and progress methodically to more difficult concepts. Each step must also be based on elements previously learned. Concepts taught must be systematically reviewed to strengthen memory" (Birsh, 2011, p. 19).
• Explicit instruction – "Explicit instruction is explained and demonstrated by the teacher one language and print concept at a time, rather than left to discovery through incidental encounters with information. Poor readers do not learn that print represents speech simply from exposure to books or print" (Moats & Dakin, 2008, p. 58). Explicit instruction is "an approach that involves direct instruction: The teacher demonstrates the task and provides guided practice with immediate corrective feedback before the student attempts the task independently" (Mather & Wendling, 2012, p. 326).
• Diagnostic teaching to automaticity – "Diagnostic teaching is knowledge of prescriptive instruction that will meet individual student needs of language and print concepts. The teaching plan is based on continual assessment of the student's retention and application of skills" (Birsh, 2011, p. 19). "This teacher knowledge is essential for guiding the content and emphasis of instruction for the individual student" (Moats & Dakin, 2008, p. 58). "When a reading skill becomes automatic (direct access without conscious awareness), it is performed quickly in an efficient manner" (Berninger & Wolf, 2009, p. 70).
• Synthetic instruction – "Synthetic instruction presents the parts of any alphabetic language (morphemes) to teach how the word parts work together to form a whole (e.g., base word, derivative)" (Birsh, 2011, p. 19).
• Analytic instruction – "Analytic instruction presents the whole (e.g., base word, derivative) and teaches how the whole word can be broken into its component parts (e.g., base word, prefix, root, and suffix)" (Birsh, 2011, p. 19).

Talking about dyslexia…

"For me, dyslexia is not a disability. The unique strengths and characteristics of dyslexia allow me to think 'outside the box'. Until I was taught the Orton Gillingham approach, I did not have the basic reading, writing, and arithmetic skills necessary for success."
— Peter W. D. Wright, Attorney for children with Special Needs