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date: 20 November 2017


Summary and Keywords

Dyslexia, or a reading disability, occurs when an individual has great difficulty at the level of word reading and decoding. Comprehension of text, writing, and spelling are also affected. The diagnosis of dyslexia involves the use of reading tests, but the continuum of reading performance means that any cutoff point is arbitrary. The IQ score does not play a role in the diagnosis of dyslexia. Dyslexia is a language-based learning disability. The cognitive difficulties of dyslexics include problems with recognizing and manipulating the basic sounds in a language, language memory, and learning the sounds of letters. Dyslexia is a neurological condition with a genetic basis. There are abnormalities in the brains of dyslexic individuals. There are also differences in the electrophysiological and structural characteristics of the brains of dyslexics. Hope for dyslexia involves early detection and intervention and evidence-based instruction.

Keywords: dyslexia, learning disabilities, reading disability, definition, cognitive processes, IQ

Dyslexia, also known as a reading disability, occurs when an individual has significant difficulty with speed or accuracy of word decoding, or with both. The comprehension of text is also affected. Spelling, handwriting, and composition difficulties usually accompany dyslexia. It is assumed that the individual has had an adequate opportunity to learn to read. Some individuals with dyslexia have difficulties with mathematics, but not all do. A mathematics difficulty (dyscalculia) is a disability in itself and can occur independently of dyslexia (e.g., Morrison & Siegel, 1991; Siegel, 2013; Siegel & Linder, 1984; Siegel & Ryan, 1988).

A Dyslexia Myth

A popular misconception of dyslexia is pervasive. The common perception of dyslexia is that it means that a dyslexic person sees and writes letters and words backward (for example, the word was read as saw, or b and d are confused). This popular myth is not true. Some people with dyslexia have this problem, but most do not. Young children who are just learning to read and write may reverse letters and words, but it does not mean that they have dyslexia. These reversal errors occur as a normal part of learning to read. In reality, dyslexia is a disability involving a number of aspects of language processing. This conceptualization of dyslexia as a visual problem and as the primary symptom being the writing of letters and words backward has been discredited by studies, including those by Liberman, Shankweiler, Orlando, Harris, and Berti (1971) and Vellutino (1979, p. 427). Although visual processing difficulties may be involved in some individuals with dyslexia, these visual difficulties are not the major problem.

Defining Dyslexia

How should we define dyslexia? Defining dyslexia has not been a simple matter. One of the major problems is that there is no specific blood test or brain imaging result that can provide a diagnosis. Fundamentally, the issue is that reading is measured on a continuum, and there is no cutoff score on a reading test that clearly divides individuals into those who are dyslexic and those who are not. The distinction between dyslexia and normal reading is arbitrary; where the cutoff point is drawn varies from study to study. At some point in the reading, the delay becomes so severe (compared with other individuals of the same age) that it is dyslexia.

Ellis (1984) used an analogy when discussing dyslexia, “Reading backwardness seems to be a graded thing more like obesity than measles. We cannot in any simple way divide the population into those who are dyslexic and those who are not, so it would seem unlikely that there will exist any symptom or sign that will quantitatively distinguish dyslexics from non-dyslexics.”

In discussing the arbitrary nature of dyslexia, Shaywitz, Fletcher, Holahan, and Shaywitz (1992a) noted, “Our findings indicate that dyslexia is not an all or nothing phenomenon, but like hypertension and obesity, occurs in varying degrees of severity … cutoffs may have no biological validity.” Exactly where the line is between dyslexic and non-dyslexic is subjective and controversial. This relative uncertainty does not dispute the reality of dyslexia, but instead indicates that there is some subjectivity in the diagnosis.

An Operational Definition of Dyslexia

There is a widely accepted definition of dyslexia. The following is an operational definition of dyslexia: Dyslexia occurs when the accuracy or fluency, or both, of word or pseudoword reading is severely impaired. This definition is becoming widely accepted and includes the critical components of dyslexia. Therefore, the two tests that are absolutely necessary for ascertaining dyslexia are a test of word-reading skills and a test of pseudoword-reading skills. It is important to use a test of single isolated word reading, such as the Woodcock-Johnson Letter Word Identification subtest or the reading subtest of the Wide Range Achievement Test (Wilkinson & Robertson, 2006). In both tests, the individual is required to read words that increase in difficulty (e.g., from simple words to complex multisyllable words, such as “cat,” “emphasis,” and “idiosyncrasy”). Test scores are compared with scores from other individuals of the same age level. For an extended discussion of the issues in the definition of dyslexia, see Siegel (1988a).

Although reading comprehension is important and is the major purpose for reading, dyslexia is best recognized by difficulties at the word level. Decoding words is critical for developing comprehension skills. Another important test for dyslexia is a test of pseudoword reading (e.g., the Woodcock Johnson Word Attack test, Schrank, Mather, & McGrew, 2014). This test involves having the person read pronounceable combinations of letters that do not represent English words but can be articulated using the pronunciation rules of English. Examples include items such as “bab,” “shum,” “cigbet” and “bafmotbem.” This is a test of basic decoding skills. Having these decoding skills is especially important when learning to read and to be able to ascertain the pronunciation of new words that have never been encountered before. Pseudowords can be developed in any language, even Chinese, and the reading of pseudowords is one of the basic tests necessary to ascertain whether or not there is dyslexia.

Measures of basic skills at the word level are used to assess the presence of dyslexia because of the complex and multidimensional level of reading comprehension tests. Reading comprehension is usually tested by having the individual read a passage and answer questions about the passage. Reading comprehension tests are usually timed. There are some individuals who, although they can read words, have difficulty with reading comprehension because they may lack the inferential skills to make sense of what they read, or because they may read slowly. They may not have sufficient background knowledge to understand the text or the questions. (For an extended discussion of these issues, see Siegel & Heaven, 1986; Siegel, Levey, & Ferris, 1985; Siegel & Metsala, 1992).

The Role of Intelligence

One of the important questions that one can ask about dyslexia is whether those who struggle with reading simply lack the intelligence to read. In the early 1960s, when the concepts of dyslexia and other learning disabilities were first developed, it was considered important to show that people who were struggling with reading or mathematics were intelligent enough to learn to read or do mathematics. One of the standard approaches to this question is to administer an intelligence (IQ) test. Individuals were required to score above a certain level to receive help for their dyslexia, although the required level varied from place to place.

Intelligence is an artificial and culturally determined construct. Some psychologists, such as Howard Gardner (2004), insist that we should think about intelligence not as a single ability but as a multidimensional construct. He postulated a number of different “intelligences,” ranging from verbal to artistic to motor intelligence. Therefore, the IQ test cannot capture the varieties of intelligence.

In the 1980s, IQ became incorporated into a simple and seemingly elegant mathematical equation. According to this equation, a learning disability occurs when the IQ score is much higher than the reading (or arithmetic) score. The difference between IQ scores and reading scores led to what is called the “discrepancy definition.” It became the basic criterion for identifying a learning disability. The discrepancy score appears mathematical and scientific, but it can result in many children being misdiagnosed. For example, in some provinces, states, and countries, if a child is a poor reader but has no discrepancy between his or her IQ score and reading score, the child is not considered reading disabled. That child is labeled “low achieving” and does not receive help for his or her problems with reading, writing, spelling, or arithmetic. To test the underlying assumptions of the discrepancy definition, two groups of children who had low reading scores were studied by Siegel (1992a). One group had reading scores that were significantly lower than their IQ scores—children who would traditionally be called dyslexic—and the other group had low reading scores, but these scores were not significantly lower than their IQ scores. These children were labeled poor readers. On a variety of reading and spelling tests, the author found that there were no differences between these two groups. The children traditionally called dyslexic and those called poor readers performed similarly when tested for reading, spelling, and phonological processing in short-term memory. The same results were found in a study with adults who had reading disabilities (Siegel & Smythe, 2004). Children with dyslexia (as defined by the discrepancy definition) made the same kind of reading errors as the children with lower IQ scores. These findings suggest that a discrepancy between IQ scores and reading scores is not relevant in identifying who has learning disabilities.

The IQ score is supposed to measure “potential,” meaning that it is assumed to predict what a person is capable of. Yet educational institutions often specify that if an IQ test score is more than three years old, it is not valid and the person must be retested. This is the ultimate absurdity. If the IQ score were a true indicator of potential, why would it change? IQ test scores are not useful in identifying learning disorders. Using IQ tests with children with learning disabilities creates a logical paradox. Most of these children have deficiencies in one or more of the component skills that are part of IQ tests—memory, language, or fine motor skills. Therefore, their scores on IQ tests will underestimate their competence.

There are a number of reasons why the discrepancy definition is illogical and does not stand up to empirical examination. One of the assumptions of the advocates for the use of the IQ test is that it presumably measures an individual’s “potential.” It is assumed that a certain degree of “potential” is necessary to develop reading skills. However, the IQ test measures, for example, vocabulary, verbal memory, and specific knowledge, and these are skills that may be deficient in the dyslexic. These skills are the result of specific learning and the measurement of them is sensitive to the educational experiences and reading behavior of the individual. Therefore, the IQ score may be an inadequate measure of the so-called intellectual potential of a dyslexic. In addition, a number of studies (e.g., Fletcher, Francis, Rourke, Shaywitz, & Shaywitz, 1992; Gustafson & Samuelsson, 1999; Siegel, 1992a) in different countries have found that there are no differences in children who have reading problems between those who have a discrepancy between IQ and reading scores and those who do not. These findings suggest that a discrepancy between IQ and reading scores is not necessary to indicate dyslexia, and that a low score on a reading test is, in fact, an indication of a reading problem. There is evidence to suggest that a child’s IQ score does not predict his or her ability to benefit from remediation (e.g., Vellutino, Scanlon, & Lyon, 2000; Vellutino et al., 1996). The discrepancy definition leads to a paradoxical situation. People with high IQ scores and average reading scores (or, in some cases, above average reading scores) are called dyslexic—just because of the difference between their scores—when they do not have a reading problem. There is also other evidence that shows that the concept of intelligence is unnecessary in diagnosing reading disabilities. One study by Siegel (1988b) divided children with reading disabilities into groups based on their IQ levels. The author compared these groups on a variety of reading and spelling tasks, and despite wide differences in their IQ levels, there were no differences between the groups on these reading tasks. Since the groups were quite similar in relation to reading-related performance, administering an IQ test would not provide useful information about how to help the children with their reading problems. Even on a reading comprehension test, a higher IQ was not sufficient to compensate for a reading disability (Siegel, 1988b).

Very recent research on brain imaging has found no differences in brain functioning between children who are dyslexic and have high IQ scores and children who are dyslexic and have lower IQ scores (Tanaka et al., 2011).


Although it seems as if it should be a simple question to answer, we do not know what proportion of the population is dyslexic. Estimates of prevalence of dyslexia, or how frequently it occurs, depend on the particular definition of dyslexia used in the study and the sample studied (Rodgers, 1983; Shaywitz, Escobar, Shaywitz, Fletcher, & Makuch, 1992b). An estimate of prevalence is specific to a particular sample and to the definition used in a study. Depending on the definition used, 5% to 10% of the population is considered to have dyslexia; however, at this point in time, any estimates given are, in reality, guesses.

Cognitive Aspects of Dyslexia

There are a number of problems with cognitive processes that are characteristic of dyslexics. Compared to other people of the same age, it is much more difficult for dyslexics to pronounce and understand the words on a page. Even when they are able to read the words correctly, they read quite slowly. The basic problem with dyslexia is what is called a “phonological skill,” that is, figuring out the sounds of letters and letter combinations. When dyslexics first learn to read, they do not know the pronunciation of the letters in a word. Even when they have learned decoding, they are slower readers than others of the same age and have much more trouble with words of two or more syllables. Children with dyslexia struggle so hard in decoding print that they sometimes forget the beginning of the word by the time they get to the end, and have to start over. Or in attacking a long word in the middle of a sentence, they may forget the beginning of the sentence.

To decode print, it is necessary to develop phonological-awareness skills. Phonological awareness, the ability to listen to speech and break it down into smaller segments, is a basic skill needed for reading. Phonological awareness is measured by asking a person to do a variety of tasks such as to say pink without the p (when we think of p, we say the sound, not the letter) or helicopter without the cop. Another task involves recognizing words that rhyme (e.g., which of the following words rhymes with cat: sun, hat, or star) or recognizing whether “cat” and “kite” start with the same sound. Another task is what is called “blending,” where individuals hear the sounds, not the letters, in a word like c–a–t, and they have to blend them together to say the word. In a task called “segmentation,” a word is said and a person is asked to say each individual sound within that word. So if they hear the word like, they have to say the l sound, the long i sound, and the sound of k. (Like has only 3 sounds but 4 letters.)

Until recently, it was widely believed that a breakthrough in the understanding of dyslexia occurred over 40 years ago, when a picture of the major cognitive difficulties in dyslexia began to emerge more clearly. Liberman and colleagues (Liberman, 1973; Liberman & Shankweiler, 1985) recognized the importance of speech and language as the basis for reading, and that children must map the written word onto the spoken word when learning to read. Reading difficulties (dyslexia) occurred when there was a deficit in these phonological processes. However, credit for this breakthrough must be given to Roza Levina, a Russian psychologist, who in the 1930s was writing about the role of phonological awareness and processing in reading and writing disorders (Chirkina & Grigorenko, 2012).

Before this breakthrough, it was assumed in the past that visual difficulties or problems with hand-eye coordination served as the basis for dyslexia. It is now clear that the major problem with dyslexia involves difficulties with phonological processing, that is, being able to segment words into their component sounds and to associate letters with their sounds and phonological awareness (i.e., the ability to segment speech into small parts, such as syllables, and the smallest units of sound, phonemes. Studies such as those by Lundberg, Frost, and Petersen (1988) and Elbro and Petersen (2004) have shown that children who receive training in these phonological-awareness skills demonstrate improved reading abilities.

One aspect of this phonological deficit is that some dyslexics show subtle difficulties in speech perception at the level of the individual sounds. Studies such as those by Godfrey, Syrdal-Lasky, Millay, and Knox (1981), Manis et al. (1997), Reed (1989), and Werker and Tees (1987) have shown that dyslexics perform more poorly than normally achieving readers on measures of speech perception. For example, Bertucci, Hook, Haynes, Macaruso, and Bickley (2003) found that the perception and production of vowels were particularly difficult for dyslexics. The speech-processing difficulties for dyslexics include weak phonological coding or vowel sounds with similar phonetic characteristics. Mody, Studdert-Kennesy, and Brady (1997) found differences between some dyslexics and typically achieving readers. As methods of speech and sound science advance, it may eventually be found that this speech-perception problem is one of the difficulties of the dyslexic.

The Role of Language Characteristics

Most of the research on dyslexia has been conducted in the English language, although that is changing. It is reasonable to ask whether the nature of the English language, with its often-unpredictable correspondences between letters and sounds, is responsible for dyslexia. As it turns out, dyslexia has the same manifestation in all alphabetic languages that have been studied and in languages that are nonalphabetical, such as Chinese and Japanese. The primary deficit is phonological (even in Chinese), although problems with visual memory, short-term verbal memory, and syntax exist in dyslexia in all languages (e.g., Ho & Bryant, 1997a).

English is the most irregular alphabetic language in the world. Consider the words have, says, said, does, should, through, and rough. You cannot pronounce them by using the letter sounds of English. Languages such as Spanish, Italian, and German are quite regular; that is, you can pronounce words just by knowing the sounds of the letters. Does the irregular nature of the English language result in more dyslexics or more difficulty for dyslexics? Dyslexia is found in all languages, and dyslexics have the same phonological problems in all languages. In a language like Mandarin Chinese, visual memory is also important. Chinese dyslexics may have visual memory difficulties in addition to phonological problems.


Some people with dyslexia often have problems with syntax or understanding the structure of the language, not necessarily major problems, but subtle ones (e.g., Siegel & Ryan, 1984, 1988). For example, dyslexics are not as proficient as good readers in predicting the missing word in a sentence that is read to them. For example, try predicting the missing words in these two sentences: “The girl … is tall plays basketball well” and “… is Susan going to the doctor today?” In the first sentence, the correct answer is “who.” Many children at age eleven or twelve can answer this correctly. Children (and even some adults) with dyslexia find the sentence difficult because of the complex construction. They usually say the missing word is “she.” In the second sentence, “when” or “why” is correct (or even “how”). Although many children at age eleven or twelve can answer this correctly, children with dyslexia are confused and often cannot think of anything to say. These difficulties indicate some problems with working memory—that is, remembering the sentence for a long enough time to be able to answer it.

Dyslexia is a language problem and means that a person sometimes lacks the abilities to remember the sounds of the letters, read long words, remember what he or she has read, and find the right words or remember what something is called. Some people with dyslexia have trouble finding the word that they want to say; when they cannot remember the name of something, they may describe it instead. For example, instead of saying “carrot,” they might say “the long and orange thing that grows in the ground.” Some people with dyslexia have more subtle difficulties with language and may make mistakes in verb tenses or vocabulary or both.

Two Routes to Reading

Scientists have used theories about reading to help understand dyslexia. One of the most widely accepted theories of reading is called the dual-route theory (Coltheart, Curtis, Atkins, & Haller, 1993). In this theory, there are two mechanisms that individuals use to read words: the direct (orthographic) route and the indirect (phonological) route. The direct route involves seeing a word and automatically knowing what it says. For frequently used words and words that have been seen before, this route is probably the one that is used. Skilled readers use this route for most of what they read, although they can use another route when they encounter words that are either new or relatively unfamiliar. The indirect route involves translating the letters into sounds and knowing the pronunciation of words from the combination of sounds. The use of this route involves what is called decoding. This route is commonly used at the beginning of the development of reading skills in which words are carefully sounded out and in more advanced readers when they encounter new words. Most dyslexics have a great deal of difficulty with this route because they lack phonological skills.


There is more to reading than learning the sounds of the letters. After the age of six, we learn most of our new vocabulary from reading. Children with reading problems do not like to read, so they spend much less time reading than good readers. As a result, they do not develop vocabulary at the same pace. One solution is to read aloud to them, as this helps develop their ear for language and improves their vocabulary. Learning prefixes and suffixes (for example, dis-, as in disapprove and disappear, or -ology, as in anthropology and sociology) and roots in words also helps build vocabulary.

History of the Concept of Dyslexia

The concept of dyslexia did not always exist. Apparently, the first person to recognize learning problems such as dyslexia was not a physician, educator, or psychologist. It was the novelist Jane Austen, who, in 1798, in her ironic novel Northanger Abbey described a child who appears to have dyslexia (Siegel, 2016). In the novel, Austen painted a picture of a young girl who had a variety of learning difficulties, and she helps us understand the gifts, as well as the problems, of children who struggle with learning. The idea of learning disabilities would not exist for another 150 years; however, Austen observed human behavior and wrote about what she saw with remarkable insights that are not unlike those of contemporary educational psychologists. Of course, she did not use the word “dyslexia”; it did not exist at that time and did not enter the language until many years later.

Jane Austen was not the only novelist to recognize dyslexia. Later, the novelist George Eliot (in reality a woman named Maryanne Evans who believed that she had to take the name of a man to get her work published) described a dyslexic boy, in 1860, in The Mill on the Floss.

Like Austen, George Eliot used her keen powers of observation to develop a central character who was dyslexic. Her portrait of a dyslexic was written almost forty years before any cases of dyslexia were described in the medical literature and a hundred years before the word dyslexia was commonly used in the English language. Her depiction of dyslexic Tom is as accurate as if she had read accounts of dyslexia in medical and educational journals.

After the writers, some physicians identified what we have come to call dyslexia. A physician, Pringle Morgan (1896) of Sussex England, reported the case of Percy, a fourteen-year-old-boy who was intelligent but could not learn to read or spell in spite of seven years of effort by his teachers. This appears to be the first example of dyslexia in a child to be described in the scientific literature. Pringle Morgan labeled Percy’s condition “congenital word blind­ness.” This rather intriguing label gives us a clue to what he thought the problem was. Pringle Morgan believed that the root of dyslexia was the inability to remember what words look like, a lack of visual memory for words. People who had this condition seemed to be unable to read words, as if they were blind. It was congenital because it was present from birth, not the result of a lack of education. Pringle Morgan believed, correctly, it was due to inadequate development of a part or parts of the brain. When Pringle Morgan dictated words to Percy, the responses were clearly incorrect. For example, for song Percy wrote scone, for subject he wrote scojock, for English he wrote Englis, for without he wrote wichout, and for seashore he wrote seasow. These errors indicate that Percy had a speech-perception problem because he could not adequately perceive sh or th sounds and could not easily write the b sound.

Percy could read numbers very well. He could do arithmetic calculations easily, but he could not solve arithmetic problems because he could not read the words. Pringle Morgan noted that “his schoolmaster, who taught him for some years, said that he would be the smartest lad in the school if the instruction were entirely oral.”

Ironically, more than a hundred years ago, Pringle Morgan foreshadowed what years later would become an important means of instruction. He recognized that children can learn orally, and that though reading is important, it is not the only way to learn about the world. Today, we encourage the use of films, videos, charts, maps, and illustrations to help people who have reading problems learn concepts.

Pringle Morgan was optimistic that a child with severe reading problems could be helped by instruction. Initially, Percy could not learn his letters; he was, in Pringle Morgan’s words, “letter blind,” but by instruction and hard work he did learn his letters, though it is not clear whether he ever became a fluent reader.

Another pioneer, James Hinshelwood (1904), a Scottish ophthalmologist, published a number of cases of “word blindness.” He described a case of a thirteen-year-old boy who could not read after seven years in school. The boy was good at drawing and “fair” at arithmetic. He could remember much of what he heard, but did not know all the letters of the alphabet. Hinshelwood recommended that children with “word blindness” should be taught reading individually, not with an entire class, so as not to experience ridicule by other children. He also recommended short lessons every day rather than long ones, another observation that is consistent with today’s approach to working with children with learning problems. He described one fifty-year-old man who could not learn to read but would always bring back the correct change when he was sent to pay a bill. Some of the children Hinshelwood tested had good auditory memories and could remember stories if they heard them. Many were slow to learn to speak. In most cases, there was a family history of reading problems, suggesting a genetic basis.

Hinshelwood recognized that children differ in the severity of their reading problems. He stated firmly that we should not treat these children and adults as “imbeciles.” Foreshadowing contemporary ideas, he encouraged teachers to use a variety of senses in teaching reading. He recognized that progress in reading would be slow but was possible with remediation.

These early pioneers in the field of learning disabilities questioned whether children with reading disabilities were just “fools”—was the problem really low intelligence? Demonstrating a wisdom that is sometimes absent today, they reasoned that if a child understood and spoke language well and could identify objects, intelligence was not the issue. Furthermore, if the child was competent at arithmetic and could write numbers, and appeared to have normal social behavior, he or she did not lack intelligence. These pioneers of dyslexia and other learning disabilities did not need expensive and time-consuming intelligence tests to distinguish between low intelligence and reading disability.

The Pioneering Work of Samuel Orton

Samuel Orton, a neuropathologist and psychiatrist in the United States, was a pioneer in the field of dyslexia. During the 1920s, he recognized that some children whom teachers called “dull, subnormal or failing or retarded in schoolwork” were not stupid but merely had severe difficulty in learning to read and write (Orton, 1925). Orton realized that these children who could not read were intelligent; they could recognize and name objects, and they understood passages that were read to them. Unlike many of his colleagues and some professionals today, he understood that scores on intelligence tests do not fairly reflect intellectual capacity. He reported the case of one boy, M.P., age 16, who had a low score on the IQ test. This boy could not visualize words and recognize them in print. Orton tested his theory about the inadequacy of IQ tests by asking M.P. questions concerning the adjustment of bearings in a V-type engine. M.P. answered quickly and with obvious ability. When Orton gave M.P. tests that required mechanical skill, his performance was in the superior range. Yet M.P. had extreme difficulties with reading and writing. He could name the letters of the alphabet but not say their sounds. His written composition was a jumble of words that made no sense, although in conversation his responses were direct and meaningful. His spelling errors were typical of those of much younger children. One of the most common methods of teaching phonics today bears his name, the Orton-Gillingham method.

Another pioneer in the field was Samuel Kirk, who coined the term “learning disabil­ities” in 1963. He defined learning disabilities as “a retardation, disorder, or delayed development in one or more of the processes of speech, language, reading, writing, arithmetic or other school subject resulting from a psychological handicap caused by a possible cerebral dysfunction and/or emotional or behavioral disturbances. It is not the result of mental retardation, sensory deprivation, or cultural and instructional factors.” This definition marked the beginning of the attempt to generalize and codify the idea of learning disabilities. All the early pioneers in the field of learning disabilities recognized that problems with certain areas of the brain were causing the reading and writing difficulties.

During the 1950s and 1960s, many social workers, psychologists, and psychiatrists blamed the families, especially the mothers, for their children’s reading problems (e.g., Miller & Westerman, 1964). The children were considered scapegoats, victims of turmoil within the family. The mothers, rarely the fathers, were the perpetrators of children’s reading problems. The mothers were labeled “non-nurturing, controlling, and seductive.” There was no analysis of the children’s reading difficulties, and few attempts to help children experiencing them.

Genetic and Neurological Basis

In the early 21st century our understanding of dyslexia is more developed and sophisticated now. Scientists have made great strides in finding the biological basis of dyslexia. Dyslexia has a genetic basis, and it is clear that dyslexia tends to run in families. Research has identified several chromosomes that appear to contain the gene or genes for dyslexia, although the exact genetic mechanisms and the inheritance patterns are not known. (For a review, see Carrion-Castillo, Franke, & Fisher, 2013). Familial studies (e.g., Fisher & DeFries, 2002; Pennington et al., 1991; Pennington, 1999; Schulte-Körne, Deimel, Müller, Gutenbrunner, & Remschmidt, 1996) and discoveries regarding the involvement of specific chromosomes (Fisher et al., 1999; Gayán, et al., 1999; Regehr & Kaplan, 1988) clearly indicate the genetic basis of dyslexia. Obviously, environmental factors play role, but the role of genetics is quite strong (Castles, Datta, Gayan, & Olson, 1999).

For example, study by Castles et al. (1999) found that phonological dyslexia (in which individuals have more trouble reading pseudowords) was more heritable than orthographic dyslexia (in which individuals have more trouble reading exception words), although both types showed a significant heritability.

There is clearly a neurological basis for dyslexia. A number of postmortem studies have indicated abnormalities in the brains of dyslexic individuals (Galaburda & Kemper, 1979; Galaburda, Sherman, Rosen, Aboitiz, & Geschwind, 1985; Geschwind & Galaburda, 1985). The universal finding is an absence of the usual asymmetry in the planum temporale. There may also be structural differences between dyslexics and nondyslexics in the corpus callosum, which controls the communication between the two hemispheres of the brain (Robichon & Habib, 1998; Robichon, Levrier, Farnarier, & Habib, 2000).

A number of electrophysiological studies have shown differences between dyslexics and typically achieving children. Event-related potentials may be used to measure the timing and the brain areas used during the cognitive processing of print and language. For example, a number of studies (Kraus & McGee, 1996; Kujala, Myllyviita, Tervaniemi, Alho, Kallio, & Näätänen, 2000; Schulte-Körne et al., 1996) have found that the event-related potentials of dyslexics, in contrast with nondyslexics, failed to show what is called “mismatched negativity,” which is a negative deflection in the wave in response to a change in the stimulus.

Functional magnetic resonance imaging has shown that there are differences in the brains of dyslexics and typical readers. The exact nature of these differences varies from study to study. In general, differences in the planum temporale have been found indicating that asymmetries are great in the typical reader, and that the direction may even be reversed in the dyslexic (Hynd, Semrud-Clikeman, Lorys, Novey, & Eliopulos, 1990; Leonard et al., 1993).

The brain network that is involved in reading spans several regions of the brain, specifically, the occipital temporal area, the temporal parietal area, and the frontal temporal area, and the inferior temporal gyrus. When children are learning letters, a region of the brain known as the visual form (occipital temporal) area supports the learning of letters. As children master the sounds of the letters there are links between the visual form area and the temporal parietal area. As reading becomes more automatic, other areas of the brain (frontal temporal and the inferior temporal gyrus) become activated. (For a more detailed description see Ozernov-Palchik & Gaab, 2016). Lower levels of activation in all these areas are characteristic of individuals with dyslexia.


Although it is a common belief that men are significantly more likely to be dyslexic than women, this assumed sex imbalance is not substantiated by newer research (Shaywitz, Shaywitz, Fletcher, & Escobar, 1990; Siegel & Smythe, 2005). There may be slightly more men than women who have dyslexia, but the difference is not significant. This notion is illustrated by a study (Shaywitz et al., 1992b) of an epidemiological sample of children in grades 2 and 3 in which reading and IQ tests were used to provide a psychometric definition of dyslexia. The investigators found that 8.7% of the boys and 6.9% of the girls were dyslexic in grade 2, and that 9.0% of the boys and 6.0% of the girls were dyslexic in grade 3. However, when they examined the sex differences in referral rates in the dyslexics identified by the teachers, they found that 13.6% of the boys and 3.2% of the girls were identified as dyslexic in the second grade, and that 10.0% of the boys and 4.2% girls were identified as dyslexic in the third grade, indicating a significant referral bias in favor of boys.

Although the actual incidence of dyslexia was similar in boys and girls, boys were much more likely to be referred for possible assessment. In general, Shaywitz et al. (1992b) found that the boys were identified because of behavioral difficulties in the classroom, which drew the teacher’s attention to them. The girls were much less likely to have behavior problems and, thus, were not identified as having reading difficulties, although they were almost as likely as boys to have a disability.

Programs to Help Dyslexics With Developing Reading Skills

There are a number of good programs to teach phonics and other reading-related skills to dyslexic children. Examples of these programs include Orton-Gillingham (Simpson, Swanson, & Kunkel, 1992), Lindamood-Bell (Simos et al., 2002), the Wilson program (Guyer, Banks, & Guyer, 1993), and Multilit (Wheldall, 2009). These programs are designed for teachers and tutors, and using them requires training. There are programs available online that can help teach children reading and writing skills; one of these programs is ABRACADABRA, an acronym for “A Balanced Reading Approach for Children Always Designed to Achieve Best Results for All.” (For a review of the studies, see Lysenko, Borokhovski, Abrami, & Wade, 2014) It helps children learn phonological awareness, phonics, reading fluency, and reading comprehension skills. Programs such as those described by Hatcher (2003) and Nicolson, Fawcett, Berry, Jenkins, Dean, and Brooks (1999) systematically teach individuals the sounds of the letters and have been found to be successful. Vaughn, Gersten, and Chard (2000) found that programs designed to enhance reading fluency or reading strategies resulted in improved reading for children with reading difficulties. Lovett et al. (1990) and Vellutino and Scanlon (1987) used a detailed program that involved training in word recognition and decoding skills to improve the reading skills of dyslexic children. Computerized programs have been helpful in some cases.

In one study, Wise, Ring, and Olson (1999) used computers to help dyslexic children. Children read books on computers that were linked to speech synthesizers and then obtained feedback on words that were difficult for them. As a result of this system, the children’s attitudes toward reading improved. Irausquin, Drent, and Verhoeven (2003) showed that computerized exercises that train speed or automatization are helpful in improving the reading of dyslexic individuals. Lovett, Warren-Chaplin, Ransby, and Borden (1994) used a computer speech-based program to train reading skills in students with dyslexia.

One of the most effective ways of teaching people with severe reading problems to read is by giving them books or magazines about topics that interest them. Fink (1988) wrote about successful people with dyslexia who were very late in developing reading skills. The successful dyslexics she interviewed, including a Nobel laureate and other professionals in fields requiring extensive reading, such as law, medicine, business, and psychology, learned to read by reading books and magazines about subjects that interested them. They had a passionate interest in a particular subject and read widely in that subject, even though they read slowly. They developed an understanding of the terminology and the basic underlying concepts and used this knowledge in their professions.

Accommodations: Technology and Other Techniques to Help Dyslexics

Compensatory techniques are strategies that are used when direct remediation may not be feasible or effective. Such compensatory techniques or accommodations offer people with learning disabilities ways to cope with difficulties in reading, writing, spelling, or mathematics. They are different than direct remedial intervention, or remedial strategies, which are attempts to directly treat the problems and try to eliminate the source of the difficulty.

Computers are essential for people who have writing problems, especially if their handwriting is illegible and difficult to read. People who struggle with writing often say that they have trouble remembering how to form the letters; they cannot think and write at the same time. Typing, and especially word processing, is very useful for these people because the fine motor coordination used in typing is much simpler than the skills involved in handwriting. One study found that children who had access to computers showed improvement in the quality and quantity of their writing (Yau, Siegel, & Ziegler, 1991). The children in this study enjoyed writing on the computer more than writing by hand. Writing an examination on a computer can also be quite helpful for those who struggle with handwriting.

Computers can be helpful to people who have spelling problems. If the computer does not find a word in its dictionary, it prompts the writer and provides alternatives. However, if you cannot spell very well, you may not be sure of which alternative to use. Poor spellers need to be taught strategies to approach spelling (see Lennox & Siegel, 1994, 1996; Siegel, 2013).

Educational accommodations include the use of computers, recording devices, screen readers, and speech recognition devices. Many dyslexics have illegible handwriting. The computer can be especially useful, particularly if touch-typing skills are learned. Computers also have spellchecking programs, which are particularly useful because dyslexics have poor spelling. Recording devices can be useful the child to record his or her ideas, which can then be transcribed later. Recording devices can also be useful in classes and lectures because note-taking skills can be a problem for dyslexic individuals. Screen readers are devices that read aloud what is on the computer screen and can be very helpful for dyslexics. Audiobooks can also be helpful. Speech recognition devices and programs are especially useful; the individual can talk into a microphone and see his or her words appear on the screen. Treatment the direct and systematic teaching of letters and their corresponding sounds (i.e., phonological skills) is an important way to help dyslexics. For a detailed review of technology and dyslexia, please see International Dyslexia Association journal Perspectives on Language and Literacy, Fall 2013 and Winter 2014.

Understanding the World of the Dyslexic

Psychologists and educators such as Barbara Riddick (1996), Isabel Shessel (1995), Janice Edwards (1994), and Barbara Guyer (1997) have interviewed people with dyslexia and other learning disabilities and have provided a picture of their experiences and feelings.

The lives of individuals with learning disabilities are filled with emotional pain, suffering, and feelings of worthlessness and stupidity. Their daily experiences at school, at home, and at work create an environment that develops and reinforces these feelings. Their self-esteem is often low and they experience anger (at themselves as well as others), frustration, depression, and ridicule.

Everyday actions and experiences can be a problem for dyslexic individuals. Many people with dyslexia experience some awkward situations every day. For example, writing checks, filling out forms, remembering telephone numbers, knowing right from left, and reading signs while driving are just some of the many challenges that they have to face. Even doors can be a problem for people with dyslexia; they may have trouble distinguishing between the words push and pull on doors. A dyslexic can get on the wrong bus by mistaking the sign “Victoria” for the intended destination “Vancouver,” or mistaking “New York” for “New Jersey.” Difficulties with finding the correct word can cause problems. One young woman related a story about being in a restaurant and ordering the “long and orange and grows-in-the-ground soup” (carrot soup). Everyone occasionally has this type of word-finding difficulty, but most people with dyslexia experience this quite often.

Some people with dyslexia report having felt lonely and terrified in school. Even teachers who are sympathetic and well-meaning sometimes find it difficult to understand how anyone cannot spell simple words or why a student has illegible handwriting. They think that the student is just not trying or is purposefully being difficult.

Teasing is quite common on the streets and playgrounds where children gather, and sometimes it gets vicious. Children with learning disabilities are often victims of bullies. Bullies tease them, call them “dummy” or “retard” or “slow” or “dumb” or “thick.” Sometimes bullies physically attack children with learning disabilities.

Many students with learning disabilities have reported that they were terrified when teachers asked them to read out loud or write on the board. They also reported experiencing physical punishment and emotional punishment—shaming, criticism, and anger—when they made mistakes or did not grasp something. Children with learning disabilities often experience physical abuse as part of their everyday experiences. The physical violence may come from their parents, their teachers, or other children Some individuals with learning disabilities have problems with finding their way around, often getting lost, and consequently being late for appointments. Some have such severe directional and spatial problems that they cannot use public transportation or drive a car.

Having dyslexia can lead to behavioral problems. Students with learning disabilities will often do anything for attention. One man confessed that he was the class leader and troublemaker, causing fights and playing tricks on other students. Other students with learning disabilities became class clowns, making rude gestures when the teacher’s back was turned.

Depression and suicidal thoughts are often a part of the lives of people with learning disabilities. Many people interviewed admitted to thoughts of suicide and of sometimes wanting to die. In a research project in Ontario, Canada, McBride and Siegel (1997) found that all of the adolescent suicides in a three-year period appeared to have had a learning disability that had not been properly identified or treated. The authors compared the grammar, spelling, and handwriting in adolescent suicide notes with how two groups of students of the same age wrote passages that were dictated to them. One group had a learning disability and the other did not. The authors found that the grammar, spelling, and handwriting problems of the students with a learning disability were the same as those in the suicide notes. The writing of the students without a learning disability was neat and correctly spelled. Recognizing that the young people who were about to attempt suicide might have been agitated and upset when they wrote their notes, McBride and Siegel also examined the notes of a group of older adults who had committed suicide because they were terminally ill and did not want to be a burden to their families. Their suicide notes were neat and often elegant, with carefully chosen language. Based on this research, a learning disability appears to be a significant factor in adolescent suicide, though certainly not the only cause.

Coping Strategies

As they relate in their interviews, many people with dyslexia have developed strategies to cope with their difficulties. One of these is humor, especially the ability to laugh at oneself. As one young person said, “I am not a slow learner; I am a fast forgetter.” Learning to advocate for themselves in educational and employment situations is essential. Many find learning and working with a team to be very important.

Social Consequences of Dyslexia

Dyslexia is a significant problem in our society. There is evidence that significant numbers of dyslexics are represented in populations of runaway homeless street youths (Barwick & Siegel, 1996) and adolescent suicide victims (McBride & Siegel, 1997) and juvenile offenders (McNamara, Willoughby, & Chalmers, 2005) It is important that we recognize these difficulties early and make an attempt to eliminate them or reduce their severity.

Delayed language development may indicate that a child is at risk for dyslexia. Children who show delayed language development at 3 and 4 years of age are at risk for dyslexia, although many children who eventually become dyslexic have perfectly normal language development. Studies (e.g., Snowling, Bishop, & Stothard, 2000) have shown that early language difficulties and a diagnosis of language impairment in childhood is predictive of reading disabilities in the later school years and during adolescence and adulthood. Although not all children who have language disorders in early childhood become dyslexic, it is a very important indicator of a possible problem; these children should be monitored very carefully.

Academic difficulties in school, especially difficulty with learning how to read, are a sign of dyslexia. Although children learn to read at different rates, if a child is having difficulty and performing significantly below his or her peers after a few months of reading instruction, the delay is a sign of a potential problem and should not be ignored.

School phobia and somatic complaints that appear on school days, especially on Monday, are signs of a possible learning disability. Prompt investigation and treatment of a possible reading problem or other learning difficulty are critical.


Prevention is the best way of avoiding the emotional and social difficulties. Stanovich (1986) provided evidence for what he called the “Matthew effect” (based on the writings of Matthew in the Bible saying that the rich get richer and the poor get poorer). Stanovich stated, “Individuals who have advantageous early educational experiences are able to utilize new educational experiences more efficiently.” In contrast, children who have reading difficulties read less and do not acquire the vocabulary and concepts that they need and, thus, fall further behind in their reading and academic skills. Obviously, we need to identify children who are at risk for dyslexia early and provide an intervention early in their school careers, before the development of secondary effects such as behavior problems.

Children at risk for reading difficulties can be identified in kindergarten (5 years of age) and intervention programs can be provided. We have found that children identified as at risk for reading difficulties in kindergarten, regardless of whether their first language was English, benefited from classroom-based intervention programs that emphasized phonological awareness, vocabulary, and reading strategies (Lesaux & Siegel, 2003; Lipka & Siegel, 2010; Partanen & Siegel, 2013). The percentage of children with dyslexia was quite small (2%).

With early identification and intervention, reading difficulties can be significantly reduced.

Further Reading

Siegel, L. S. (2016). Not stupid, not lazy: Understanding dyslexia and other learning disabilities. Baltimore: International Dyslexia Association.Find this resource:

International Dyslexia Association.

Dyslexia International.


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