Dyslexia

Dyslexia is a brain disorder that primarily affects a person’s ability to read and write. In fact, the word’s Greek roots simply mean "language problems."

Dyslexia is the best known of the specific learning disabilities—problems with mastering particular types of information, such as numbers or spatial relations, rather than low intellectual performance in general. Dyslexia is also the best defined of these problems, and the best understood. Although these disorders originate in the brain, they are not medical problems in the sense that a physician or surgeon can cure them. Instead, the accepted treatment for dyslexia and similar conditions consists of specific, structured forms of training. In rare cases, a person starts to suffer dyslexia because of a stroke (ischemic, hemorrhagic) or injury affecting particular parts of the brain. Much more often, dyslexia appears as a developmental disorder in childhood. Some toddlers have difficulty learning to speak: a delay occurs in normal speech development between two and three years of age, or the children frequently mispronounce words. These children seem to be at higher risk for developing dyslexia, and parents should watch their progress carefully so that they can receive appropriate education as soon as they enter school. Usually, however, parents have no clues about their child’s possible dyslexia before he or she first encounters reading and writing. Most children easily learn the basics of how to read in kindergarten or first grade, but dyslexics do not. Schoolteachers and parents can often tell that a child is having difficulty as soon as reading lessons begin. It is important to help these children from the very start and to track their progress closely. However, it is unreasonable to label a child at that level because many children who start reading slowly will catch up with most of their peers within two years. To make a diagnosis of dyslexia, most specialists look for a discrepancy between a child’s chronological age and his or her reading age, with a two-year gap being the most common indicator. Children usually begin to read in kindergarten or first grade, when they are 5 or 6. In theory, therefore, the problem cannot be spotted until children reach age 7 or 8, in the second or third grade. An 8-year-old dyslexic would be reading at a first-grade level or below. Another important indicator that a child might have dyslexia is whether members of his or her family have been diagnosed with the disorder or have a history of reading problems. As many as 50 percent of children from families with dyslexia will exhibit the learning disability during the school years. However, in previous generations, schools recognized dyslexia much less often; a parent or other relative may therefore not be aware of the root of his or her own frustrations with reading. Sometimes uncomfortable memories of school affect how parents react to the possibility that their child is dyslexic; some resist such “labeling” and the special lessons that go with it. In other families, learning that a mysterious problem has a history and a name actually comforts parents and makes them more eager to help their child overcome it. There are no brain markers for dyslexia, so ordinary computerized axial tomography (CAT) scans, magnetic resonance imaging (MRI), or electroencephalograms (EEGs) are no help in diagnosing it. A physiological test called event related potentials (ERPs), which clinicians can do as early as infancy, has been shown to predict which groups of children are more likely to develop dyslexia, but this test cannot forecast the course of an individual child’s development. Misconceptions and Realities A diagnosis of dyslexia implies nothing about a child’s intelligence, emotional makeup, neurological health, or cultural and educational potential. Some bright children have dyslexia; so do some children who are mildly retarded in overall learning. Sometimes children with dyslexia suffer emotional problems, either because of their frustration in school or because of other factors. These students’ feelings can make it harder for them to deal with the language problem and learn ways around it, but their emotional states do not cause or worsen the disorder. Culture plays a role in dyslexia, of course. The condition could not be identified in an illiterate society. Furthermore, the language a child grows up using affects how hard it is to overcome the disorder. English is problematic for dyslexics because it contains many inconsistencies between sounds and their written symbols. In contrast, modern Italian is more uniform in spelling and pronunciation, and fewer young Italians seem to have problems with dyslexia. Nonetheless, there is no evidence to support the notion that such cultural factors as different ways of teaching children to read cause dyslexia. In every major culture today, being able to read and write well is a gateway to further education and success. Dyslexics often lose out on opportunities because of their disability. Many trickle to the bottom of the socioeconomic ladder, and more than a fair share even take to criminal behavior. Low self-esteem and its many psychiatric complications are common. These problems are not due to anything inherent in dyslexics’ brains but to a lack of adequate educational interventions when they were young. Recent research and publicity have increased public awareness of dyslexia, and common misconceptions that these children are lazy and irresponsible—that they just aren’t trying to learn—have begun to fade. Today the controversies surrounding dyslexia usually involve scarce resources and perceptions of fairness. In many communities, school budgets and teachers’ time are stretched thin. How much of those precious resources, people ask, should be devoted to special education? Should a child who has dyslexia but few other difficulties receive extra time and attention? If a child has trouble reading along with other cognitive problems, such as attention deficit/hyperactivity disorder (ADHD) or poor memory, what is the most appropriate way to assist him or her? Does identifying some children as dyslexic label them as inferior and unlikely to catch up with their peers? Would it be better for these children’s self esteem and education to say they have a “learning difference,” not a “disability”? Semantics aside, our society seems to have reached a consensus that schools should help all children learn to their full potential, even if some need special attention more frequently than others. (We all need special attention sometimes, after all.) Another flash point is the flexibility some dyslexics request on assignments, standardized tests, and other classroom challenges. Is it fair for a dyslexic student to have extra time to read an exam or write an essay, or assistants to take notes and read textbooks aloud? Some people speak of dyslexia as a “fancy label for unsuccessful rich kids,” even though all socioeconomic classes are touched by the problem. It is important to realize that dyslexia is not a catchall term for trouble in school, or even trouble with reading; it is a diagnosis of a brain condition based on specific, scientifically based criteria. Simply because dyslexic children look like most of their peers and exhibit a wide range of aptitudes doesn’t mean that they aren’t all working to overcome a real problem. Forms of Dyslexia For most dyslexics, the disorder involves the ability to understand the sound structure of their native tongue. To learn to read and to acquire new written words throughout life, we must match a visual symbol (a grapheme, such as a letter) to a speech sound (a phoneme). As we speak or comprehend what others say, we are not conscious of the individual sounds that make up words, even though we must have representations of these sounds in our minds. But to learn to read, we must become aware of which individual sounds correspond to which letters. Reading involves seeing the correspondence between the sights and sounds of language. Dyslexic children most often have problems consciously recognizing the sounds of their native language. This form of the disorder, known as phonological dyslexia, can be revealed by various challenges: rhyming, decoding pig Latin, breaking words into segments, identifying words after the removal of one phoneme. Dyslexics of this sort also have trouble reading pseudowords like cattigen, teepress, and berticks because they cannot map individual letters to the sounds they correspond with. Known words are easier to recognize because we can assemble clues: a familiar visual feature, the word’s general shape, its context. Such pointers probably help all of us recognize words, but for dyslexic readers they are crucial. (In fact, some children with dyslexia become very adept at such skills and at otherwise masking their difficulties with reading and writing.) Autopsy studies of phonological dyslexics indicate that the brain areas involved in language processes can develop minor malformations during the fetal period. Imaging studies of such people using language or performing other cognitive tasks show dysfunction in the parts of the cerebral cortex that are involved in phonological processing and auditory-visual association. All of this points to phonological dyslexia as an innate, constitutional problem that arises during early brain development and becomes apparent only when a child is exposed to reading. In contrast, some dyslexics (probably a small proportion, but the exact numbers are not known) have no unusual problems handling speech sounds. They can read pseudowords with ease. These dyslexics have trouble only with irregular words, such as enough, yacht, and naive. This form of the disorder is known as surface dyslexia. In stroke and brain injuries, the site of the lesion that produces problems with reading irregular words is different from that causing problems with pseudowords. It should therefore be the case that the two forms of developmental dyslexia, phonological and surface, have separate brain mechanisms. This, however, has not yet been proven. An even rarer form of the disorder is called deep dyslexia. This type of reading disorder can appear after diffuse brain injury or in conditions such as Alzheimer’s disease. It consists of reading words as other words related to them in meaning—for instance, chair for table. Deep dyslexia is rare in the West, but may be more common for children learning to read languages like Chinese, where the visual forms of words with related meanings may be quite close to one another. Dyslexics may also have problems with processing rapidly changing sounds not involved in language. It is not clear how many people have this difficulty, however, or how it affects learning to read. Little is known about the biological factors that increase the risk for developmental dyslexia. There is no evidence to support the idea that dyslexia results from a pregnant mother’s ingestion of toxins or from direct injury to the fetus. On the other hand, there is certainly a genetic component, as the condition tends to run in families. Several studies have implicated genes on chromosomes 15, 6, 1, and 2, each occurring in different families. This suggests that there are probably several independent genetic causes of dyslexia. It is also possible that different genes are associated with different types of the disorder—a gene on chromosome 6 with the phonological form, for instance. No specific gene or genes have been identified, however. Getting to the biological roots of dyslexia is difficult because the disorder is so complex. We expect that genetic research will lead to improvements in classifying dyslexia into different types, each of which will respond to a different treatment. Even based on what we know today, there is no reason to expect that one educational program will work for all dyslexics. Discovering early markers for a high risk of developing dyslexia will also allow educators to intervene earlier and probably produce better outcomes for students. Helping a Child Overcome Dyslexia The treatment of dyslexia is seldom medical. Rather, it is most often treated educationally, with specially designed tutoring that relies heavily on phonological training. If, however, a student is also suffering from ADHD, depression, anxiety or epilepsy, a physician may treat these conditions to improve the child’s general cognitive function and thus increase the benefit of the educational program. The treatment should begin soon after specialists confirm the diagnosis of dyslexia. Most states define special-education procedures by law as a way to ensure that every child in public schools can benefit. Schools start by alerting the student’s parents to the situation and proposing a program of lessons tailored to help the child overcome his or her specific difficulties. Educators can take no special steps without the parents’ approval, but parents cannot dictate every detail of their children’s education; teachers and families need to work together. There is usually a regular schedule for evaluating the child’s progress and revising the program as needed. Dyslexia treatments almost always consist of structured lessons in language use and especially in reading. These usually require students to work for at least part of the school day with a teacher alone or in a small group, away from the distractions of a larger class. Students’ reading strategies change with practice and maturity. The letter-by-letter approach that is crucial when a child is just beginning to read becomes less important later. As students grow older, they also become more aware of what’s most difficult for them and how they can manage those reading challenges. A more recent approach to dyslexia involves training children to recognize rapidly changing sounds; this is based on the finding that many dyslexics experience difficulties with such sounds. However, the jury is still out on whether this treatment helps with reading. The best evidence indicates that no matter what other treatments are employed, dyslexics still need specific reading instruction. The improvement of a child’s dyslexic symptoms depends on the severity of the problem, his or her general intelligence, the age when treatment begins, and the parents’ support. Early recognition is an important factor. Unfortunately, fiscal considerations often determine how early and to what extent children can receive appropriate help. As ongoing research discloses what portion of reading problems relate to perceptual deficits, visual and auditory, and what part is cognitive and linguistic, specialists will introduce newer and more effective treatments. Most people with dyslexia can eventually read at near normal levels with good comprehension. They may always have problems with spelling and learning foreign languages. Often continued difficulties or a return of the problem after a period of improvement can be linked to changes in demand (for example, college suddenly requires much more reading) or other problems (inadequate sleep, depression, anxiety, abuse of alcohol and more). Overcoming these separate challenges can put young people back on track for progress with reading. Adults with dyslexia have succeeded in many fields, including finance, film, politics, art, and even creative writing, so the condition does not have to limit a person’s accomplishments.