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What Is Dyslexia

Authors: Roger P. Harrie and Carol Weller



ERIC Clearinghouse on Handicapped and Gifted Children, Reston, Va


For More Information

What Factors Contribute To Dyslexia?

What Are Some Of The Characteristics Of Dyslexia?

How Is Dyslexia Diagnosed?


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Dyslexia is a term that has been loosely applied to reading disabilities. Specific definitions for dyslexia vary with disciplines. Those in medicine define dyslexia as a condition resulting from neurological, maturational, and genetic causes, while those in psychology relate dyslexia on the basis of the specific reading problems evidenced and give no reference to causation. All disciplines would probably agree that dyslexia is evidenced by persons of otherwise normal intellectual capacity who have not learned to read despite exposure to adequate instruction.

How Is Dyslexia Diagnosed?

The diagnosis of dyslexia usually begins with an awareness by parents or teachers that a problem in reading exists. A physician is often the first diagnostician to explore the nature of the difficulty. The medical practitioner should investigate the cause of the reading problem by conducting a complete physical examination and obtaining a comprehensive health history. If indicated, the child should be referred for a neurological examination. If dyslexia is suspected, the physician should refer the child for further evaluation and treatment by a specialist in psychoeducational diagnosis.

The major purpose of the diagnostic process is to isolate the specific difficulties associated with dyslexia and to suggest appropriate educational intervention. Usually the diagnostician will employ a battery of assessment instruments that explore the relationship of specific reading problems to the intellectual, achievement, perceptual, motoric, linguistic, and adaptive capabilities of the individual. Based on the results, an intervention plan can be implemented by a special educator or remedial reading teacher trained in specialized reading techniques. No one remedial reading method works for all reading disabled students. Therefore it is important that the teacher have mastery of many different techniques.

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What Are Some Of The Characteristics Of Dyslexia?

An individual is identified as dyslexic when a significant discrepancy exists between intellectual ability and reading performance without an apparent physical, emotional, or cultural cause. Common findings in the history include, but are not limited to: (1) family history of reading problems; (2) a predominant occurrence in males (males to females 8:1); (3) an average or above average IQ and, not uncommonly, a proficiency in math: (4) no enjoyment of reading as a leisure activity; (5) problems of letter and word reversal; (6) developmental history of problems in coordination and left/right dominance; (7) poor visual memory for language symbols; (8) auditory language difficulties in word finding, fluency, meaning, or sequence; (9) difficulty transferring information from what is heard to what is seen and vice versa.

Specific reading problems associated with dyslexia include difficulty in pronouncing new words, difficulty distinguishing similarities and differences in words (no for on), and difficulty discriminating differences in letter sound (pin, pen). Other problems may include reversal of words and letters, disorganization of word order, poor reading comprehension, and difficulty applying what has been read to social or learning situations.

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What Factors Contribute To Dyslexia?

Ocular Problems

Several reliable studies (Helveston 1969; Blika 1982; Keys 1982; Hiatt 1984) have found that dyslexic individuals have no greater incidence of eye problems than do individuals with normal reading ability. Such parameters as visual acuity, stereo acuity, ocular alignment and motility, fusion status (break point amplitude), and refractive error have not been shown to be significantly different in poor versus normal readers. Individuals with reading problems should, however, have a careful eye examination as part of an overall medical examination. There is no scientific evidence that visual training (including eye muscle exercises, ocular tracking or pursuit exercises, or glasses with bifocals or prisms) leads to significant improvement in the performance of dyslexic individuals.

Language Problems

According to Mattis (1978), the primary contributing factor to dyslexia is an auditory language deficit. Approximately 86% of the individuals identified as dyslexic evidence an auditory language disorder that prevents the individual from linking the spoken form of a word with its written equivalent. In light of this, any individual with reading problems should have a careful evaluation of his or her language capabilities and where indicated, appropriate speech and language intervention should be provided.

Visuo-Spatial-Motor Problems

In contrast to language problems, visuo-spatial-motor factors of dyslexia appear less frequently (Robinson and Schwartz 1973). Approximately 5% of the individuals identified as dyslexic have a visuo-spatial-motor problem that interferes with sequential organization, scanning, and the perception of temporal and spatial cues. Although visuo-spatial-motor confusion is common in young children who are just learning to read, these problems do not tend to account for severe and persistent reading difficulties unless the child has missed so much basic reading instruction that he cannot get caught up. Assessment of visual, spatial, and motor capacities should be included in the diagnosis of any coordination or orientation disorder; however, there is no scientific evidence that interventions such as neurological and sensory organizational training, laterality training, dominance training, balance beam, or reflex inhibition will significantly accelerate reading performance.

Other Factors

The importance of general intelligence in learning to read has been examined and shown to be a critical factor in both reading and language abilities. Investigations of the role of dominance in handedness, eyedness, and mixed laterality have produced no consistent conclusions. Studies investigating low birth weight, EEG abnormalities, temperamental attributes, attention deficit disorders, birth order, food additives, and chemical allergies have yielded mixed results. What is clear is that a wide range of factors can be associated with reading difficulties but that these factors work differently in different children. There is no simple formula for diagnosing and treating a dyslexic child. Each one requires his or her own individual program.

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For More Information

Benton, A. L., and D. Pearl. DYSLEXIA. New York: Oxford University Press, 1978.

Blika, S. "Opthalmological Findings in Pupils of a Primary School with Particular Reference to Reading Difficulties." ACTA OPTHALMOLOGICA 60 (1982):927-934.

Helveston, E. M. "Editorial." THE SIGHT SAVING REVIEW 39 (1969):1.

Hiatt, R. L. "Reading Problems and the Opthalmologist." ANNALS OF OPTHALMOLOGY 16 (1984):116-122.


Mattis, S. "Dyslexia Syndromes: A Working Hypothesis." In DYSLEXIA, edited by A. L. Benton and D. Pearl. New York: Oxford University Press, 1978.

Robinson, M. E., and L. B. Schwartz. "Visuo-motor Skills and Reading Ability: A Longitudinal Study." DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY 15 (1973):281-286.

Rourke, B. P. "Neuropsychological Research in Reading Retardation, A Review. In DYSLEXIA, edited by A.L. Benton and D. Pearl. New York: Oxford University Press, 1978.


ED262500 84 What Is Dyslexia: 1984 Digest.
Authors: Harrie, Roger P.; Weller, Carol

ERIC Clearinghouse on Handicapped and Gifted Children, Reston, Va.


This publication was prepared with funding from the Office of Educational Research and Improvement, U.S. Department of Education, under OERI contract. The opinions expressed in this report do not necessarily reflect the positions or policies of OERI or the Department of Education.

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