Dyslexia

Dyslexia is a type of specific learning disability that impairs a person's ability to read. Individuals with dyslexia typically read at levels significantly lower than expected despite having normal intelligence. Difficulties with spelling, writing, speaking, and working memory may co-exist. Dyslexia affects individuals throughout their lives and is referred to as a disability because it can be difficult for a student to succeed academically in the typical classroom environment.

Types

Developmental dyslexia

Developmental dyslexia, also called congenital word-blindness is present from birth, develops during childhood and does not result from trauma to the brain.

Acquired dyslexia

Aquired dyslexia results from brain injury, usually to the left hemisphere.

Signs and Symptoms

The problems displayed by individuals with dyslexia involve difficulties acquiring and using language. Reading and writing letters in the wrong order is just one manifestation of dyslexia and does not occur in all cases.

Other problems experienced by dyslexics involve:

• Learning to speak
• Organizing written and spoken language
• Learning letters and their sounds
• Memorizing number facts
• Spelling
• Reading
• Learning a foreign language
• Correctly doing math operations

Not all students who have difficulties with these skills are dyslexic. Formal testing is the only way to confirm a diagnosis of suspected dyslexia.

Adults

The difficulties noted below are often associated with dyslexia if they are unexpected for the individual's age, educational level, or cognitive abilities. A qualified diagnostician can test a person to determine if he or she is truly dyslexic. An adult with dyslexia may:

• Hide reading problems
• Spell poorly and rely on others to correct spelling
• Avoid writing or may not be able to write
• Often be very competent in oral language
• Rely on memory or have an excellent memory
• Have good "people" skills
• Be spatially talented. Professions include, but are not limited to, engineers, architects, designers, artists and craftspeople, mathematicians, physicists, physicians (esp. surgeons and orthopedists), and dentists.
• Be very good at "reading" people (intuitive)
• In jobs, often work well below their intellectual capacity
• Have difficulty with planning, organization and management of time, materials and tasks.
• Often be entrepreneurs

Children

Signs of dyslexia in young, preschool children include talking later than expected, a slowness to add new words, difficulty rhyming, and trouble following multistep directions. After a child begins school, the signs of dyslexia include:

• Difficulty reading single words, such as a word on a flashcard
• Difficulty learning the connection between letters and sounds
• Confusing small words, such as at and to
• Letter reversals, such as d for b
• Word reversals, such as tip for pit

Having one of these signs does not mean a child has dyslexia. Many children reverse letters before the age of 7. But, if several signs exist and reading problems persist, or if there is a family history of dyslexia, this may warrant having the child evaluated.

Causes

The exact causes of dyslexia are still not completely clear, but anatomical and brain imaging studies show differences in the way the brain of a dyslexic person develops and functions. ^[1] There also appears to be a genetic factor in the development of dyslexia. A likely gene and chromosome have even been identified. ^[2] Moreover, most people with dyslexia have been found to have problems with identifying the separate speech sounds within a word and/or learning how letters represent those sounds, a key factor in their reading difficulties.

Diagnosis

There is no single diagnostic test for dyslexia. The diagnosis is made through an evaluation process which has several parts:

History

History is very important in the diagnosis of dyslexia. A family history may be relevant as dyslexia tends to run in families. ^[3]

A history of speeech and/or language development may also help with the diagnosis of dyslexia, especially in the context of a family history of dyslexia. ^[4]

A normal prenatal and birth history is usually present with dyslexia.

Children with dyslexia may not be identified in the very early years of school (preschool and kindergarten). Difficulties may present when the child has difficulty learning to read and write in the early elementary years.

The following are normal developmental behaviors among 1st, 2nd or 3rd-Graders:

• Remembering simple sequences such as counting to 20, naming the days of the week, or reciting the alphabet
• Having an understanding of rhyming words, such as knowing that fat rhymes with cat
• Recognizing words that begin with the same sound (for example, that bird, baby, and big all start with b)
• Easily clapping hands to the rhythm of a song
• Frequently using specific words to name objects rather than words like “stuff” and “that thing”
• Easily remembering spoken directions
• Remembering names of places and people
• Showing understanding of right-left, up-down, front-back
• Sitting still for a reasonable period of time
• Making and keeping friends easily

Answering “no” to most or all of these questions may indicate a learning disability. Not all students who have difficulties with these skills are dyslexic. Formal testing is the only way to confirm a diagnosis of suspected dyslexia.

Testing

There are a number of screening tests that may be able to identify reading problems in young children in early stages. Examples of these tests include the Predictive Assessment of Reading (PAR); Dynamic Indicators of Basic Early Literacy Skills (DIBELS); Texas Primary Reading Inventory (TPRI); and AIMS web screening assessments ^[5] Tests of language skills, memory and rapid naming are more relevant in younger children (kindergarten and early first grade) than tests of spelling, reading and decoding.

• Intelligence (IQ) tests were considered part of the evaluation for dyslexia in the past. They are no longer required as it is now believed that oral language abilities (listening and speaking) are a better predictor of reading and spelling rather than intelligence, as was previously believed.
• Although early language delay is often present in children with dyslexia, higher level language skills are usually age-appropriate. Any later language problems should be referred to a speech pathologist for diagnosis.
• Word recognition (the ability to read printed words) may be accurate in children with dyslexia, but speed of recognition is generally slower than expected.
• Spelling is generally the weakest area in children with dyslexia and also the most difficult to correct.
• Children with dyslexia often have difficulty identifying, pronouncing or recalling sounds. Tests for these skills are called tests of phonological processing.
• Naming tests, where the child is asked to quickly name an object, color, letter or number, are generally abnormal (slow) in dyslexia.
• Because students with dyslexia may have strong oral language skills, their reading comprehension may be normal. They may still have difficulty reading and comprehending longer books or assignments in school.
• Vocabulary helps with understanding of the written or spoken word. Both oral and written vocabulary tests should be administered in the evaulation of dyslexia.

Compiling the data

The pattern of strengths and weaknesses determined from testing varies greatly with age, educational experience and environmental factors. There are patterns that generally emerge and help with diagnosis. ^[5]

• Family history/early development: history of reading or spelling difficulties or diagnosis of dyslexia among family members; normally birth and prenatal history; difficulty in early speech and language.
• Early childhood/primary grades: difficulty learning the alphabet, sounds and letters; rhyming; learning the rules for spelling; remembering small words that are not usually sounded out (and, or, the); better listening comprehension than reading comprehension.
• Middle and high school: reluctant to read; slow reading with frequent sounding out of words; poor spelling; non-fluent writing; weak use of vocabulary; may mispronounce common words.

The data is compiled and a written report is generated. The diagnosis of dyslexia is made by a professional such as a psychiatrist, psychologist or speech-language pathologist who is able to interpret the data correctly.

Treatment

The main focus of treatment is usually on the specific learning problems of affected individuals. The usual method is to identify the specific weaknesses and and tailor the treatment to concentrate on those areas. This is called intervention planning

In addition, once the specific weaknesses are identified and the diagnosis is made, documentation should be provided to the school system so that eligibility for special services (special education) should be provided, if applicable. The eligibility guidelines are set by the government but vary from state to state.

Medicines

Medicine is generally not used to treat dyslexia. Since it is a condition and not a disease, the underlying problem cannot be treated medically. Occasionally, medicines are used for co-existing conditions like Attention Deficit-Hyperactivity Disorder (ADHD)

Living with Dyslexia

The impact that dyslexia has is different for each person and depends on the severity of the condition and the effectiveness of instruction or remediation. The core difficulty is with word recognition and reading fluency, spelling, and writing. Some dyslexics manage to learn early reading and spelling tasks, especially with excellent instruction. Later, they may experience more difficulties when more complex language skills are required, such as grammar, understanding textbook material, and writing essays.

People with dyslexia can also have problems with spoken language, even after they have been exposed to good language models in their homes and good language instruction in school. They may find it difficult to express themselves clearly, or to fully comprehend what others mean when they speak. Such language problems are often difficult to recognize, but they can lead to problems in school, in the workplace, and in relating to other people. The effects of dyslexia reach well beyond the classroom.

Dyslexia can also affect a person’s self-image. Students with dyslexia can sometimes feel “dumb” and less capable than they actually are. After experiencing a great deal of stress due to academic problems, a student may become discouraged about continuing in school. In its more severe forms, dyslexia qualifies a student for special education, special accommodations, or extra support services.

Expected Outcome

For those with dyslexia, the prognosis is mixed. The disability affects such a wide range of people, producing different symptoms and varying degrees of severity, that predictions are hard to make. The prognosis is generally good, however, for individuals whose dyslexia is identified early, who have supportive family and friends, who have a strong self-image, and who are involved in a proper remediation program.

Related Problems

Related disorders

An individual can have more than one learning or behavioral disability. In various studies as many as 50% of those diagnosed with a learning or reading disorder have also been diagnosed with ADHD. Although disabilities may co-occur, one is not the cause of the other.

Dyslexia and ADHD have some similar features. Dyslexic children, like children with ADHD, may have difficulty reading. In the case of dyslexia, reading may cause fatigue because it is demanding, while difficulty paying attention may cause reading problems in ADHD. The difference is that the dyslexic person’s reading is typically characterized by major problems with accuracy and misreading large and small words. The person with ADHD may not be a fluent reader, but does not typically misread words.

Chances of Developing Dyslexia

Prevalence

The prevalence of dyslexia has been estimated at 5% to 10% ^[6].

Risk factors

The primary risk factor for developmental dyslexia appears to be genetic. A number of probable chromosomes have been isolated, as have four specific genes. ^[6]

Because there are several different causes of aquired dyslexia, the risks are varied. For example, poorly controlled high blood pressure or atherosclerosis may increase the risk of dyslexia due to stroke.

Clinical Trials

ClinicalTrials.gov: Dyslexia Clinical Trials has a list of ongoing clinical trials. Some of the ongoing trials involve:

• Whether medicines containing dopamine may help with reading, spelling and writing.
• The use of the medication atomoxetine to treat patients with ADHD and dyslexia.
• Therapy for aquired dyslexia
• Using MRI to evaluate brain development in children with several different disorders, including dyslexia.

Research

Recent discoveries

Recently concluded clinical trials studied:

• Whether the medication atomoxetine (Strattera), a norepinephrine reuptake inhibitor used in the treatment of ADHD, has a role in treating dyslexia
• The National Institutes of Health completed a ten year study to investigate the biological and educational constraints of children with learning disabilities, with a focus on treatment and links between assessment and treatment. The project evaluated prevention and treatment of reading and writing disabilities, the genetic contribution to subtypes of dyslexia, the relationship between brain variables and dyslexia, and the brain's response to treatment for dyslexia. Genetic and brain imaging studies were an ongoing part of the study.
• Using computer-based visual and auditory multimedia training to improve writing performance in developmental dyslexia. ^[7]

References

1. ↑ Chang BS, Katzir T, Liu T, et al. A structural basis for reading fluency: white matter defects in a genetic brain malformation. Neurology. 2007 Dec 4;69(23):2146-54. Abstract
2. ↑ McGrath LM, Smith SD, Pennington BF. Breakthroughs in the search for dyslexia candidate genes. Trends Mol Med. 2006 Jul;12(7):333-41. Epub 2006 Jun 16. Abstract
3. ↑ Snowling MJ, Muter V, Carroll J. Children at family risk of dyslexia: a follow-up in early adolescence. J Child Psychol Psychiatry. 2007 Jun;48(6):609-18. Abstract
4. ↑ Lyytinen H, Ahonen T, Eklund K, et al. Early development of children at familial risk for dyslexia--follow-up from birth to school age. Dyslexia. 2004 Aug;10(3):146-78. Abstract
5. ↑ ^{5.0 5.1} International Dyslexia Association. Testing and Evaluation fact sheet
6. ↑ ^{6.0 6.1} Shastry BS. Developmental dyslexia: an update. J Hum Genet. 2007;52(2):104-9. Epub 2006 Nov 17. Abstract
7. ↑ Kast M, Meyer M, Vögeli C, Gross M, Jäncke L. Computer-based multisensory learning in children with developmental dyslexia. Restor Neurol Neurosci. 2007;25(3-4):355-69. Abstract

External Links

The International Dyslexia Foundation

National Center for Learning Disabilities

Learning Disabilities Association of America