When Was Dyslexia First Diagnosed and Recognized as a Learning Disability?

The History of Diagnosing Dyslexia

Dyslexia is a common learning disability that affects the way the brain processes written and spoken language. People with dyslexia often have difficulties with reading, writing, spelling, and pronunciation. While dyslexia is often detected and diagnosed in childhood, it was not always recognized as a distinct learning disability.

The first descriptions of the characteristics of dyslexia date back over 100 years. In the late 19th and early 20th centuries, doctors and researchers began documenting cases of children who unexpectedly struggled with reading, writing, and language skills. However, it took many decades of study before the underlying cause was identified as a learning disability that came to be known as dyslexia.

Early Documented Cases

One of the earliest medical papers describing dyslexia was published in 1887 by a British physician named Pringle Morgan. In the paper, Morgan described a 14-year-old boy who had significant difficulties with learning to read and write, despite having normal intelligence and sensory abilities. Morgan termed the boy's condition "congenital word blindness" and hypothesized it was caused by a defect in the brain's visual center.

A few years later in 1896, a British doctor named W. Pringle published a study of a small group of boys who struggled severely with learning to read and had poor spelling abilities. Pringle suggested these cases demonstrated a selective defect in the development of the brain rather than an overall intellectual disability.

These early reports established that reading and language disabilities could occur in children of normal intelligence and without obvious sensory problems like impaired vision or hearing loss. This contradicted the widely held belief at the time that reading difficulties were solely caused by lack of mental ability or poor vision.

Advent of the Term "Dyslexia"

In 1887, a German neurologist and psychiatrist named Rudolf Berlin first coined the term "dyslexia." Berlin used the term to refer to a case of a boy who had extreme difficulty learning to read and write properly despite showing talent in other academic areas. However, Berlin's proposed term did not gain widespread usage at the time.

In 1917, American neurologist Samuel Orton independently revived the term "dyslexia" in a report describing reading disabilities in a group of adults who had struggled with reading since childhood. Orton noted that some of their reading difficulties involved reversing the order of letters within words, which he termed "strephosymbolia."

Through the 1920s and 1930s, Orton and his colleagues published extensive studies on reading disabilities in children and adults, popularizing the term "dyslexia" to describe the condition. Orton hypothesized that dyslexia was caused by delays in establishing dominance in the left hemisphere of the brain, which controls language in most people.

Dyslexia Research Expands

In the 1930s and 1940s, the British neurologist Macdonald Critchley conducted groundbreaking research providing additions insights into dyslexia. Critchley proposed using the term "developmental dyslexia" to specify reading disabilities with a neurological origin present from birth.

Critchley also made key observations about the wide variations in the severity and manifestations of reading disabilities in different cases. His detailed descriptions of the dyslexic profile, including left-right confusion and poor sequencing abilities, helped distinguish dyslexia from other learning disorders.

During this period, research began providing concrete evidence that dyslexia had a neurobiological basis and was not due to lack of intelligence or poor environment. Studies also showed that dyslexia persisted into adulthood if not remediated during school years.

Dyslexia Research in the 1950s-1970s

In the 1950s and 1960s, research on dyslexia began incorporating new knowledge about how language and reading are processed in the brain. Neurologist Norman Geschwind studied left-handedness and language abilities, shedding light on brain lateralization and language development.

In the 1960s, it became more widely recognized that slow progress in reading instruction, now termed "developmental dyslexia," required evaluation by specialists. This led to the establishment of learning disability clinics focused specifically on diagnosing and treating children with unexplained reading difficulties.

New research also revealed the hereditary nature of dyslexia, showing it tended to run in families. Studies found that dyslexia affected boys more frequently than girls at a ratio of about 3 or 4 to 1.

The Orton Dyslexia Society was founded in 1949 to promote research, education, and services for individuals with dyslexia. In the 1960s, the organization began providing training and certification for specialists in treating dyslexia.

Standardized Diagnostic Testing for Dyslexia

A major development in identifying dyslexia was the creation of standardized tests to diagnose reading disabilities. In 1963, New Zealand psychologist Aileen Taylor developed the first such assessment tool, naming it the Psycholinguistic Abilities Test.

Taylor's test measured individual skills involved in the reading process, such as visual perception and phonemic awareness. Test results helped identify children struggling with key components of reading, allowing dyslexia to be differentiated from other learning disabilities.

In the 1970s and 1980s, other diagnostic reading tests were developed, including the Dyslexia Screening Instrument. Standardized testing for dyslexia became widely used by psychologists and schools to identify and evaluate struggling readers.

Recognition as a Learning Disability

A landmark event in the history of dyslexia was its inclusion in the first formal definition of learning disabilities in 1968. The definition was created by the National Advisory Committee on Handicapped Children in the U.S., which designated dyslexia as one of seven categories of learning disabilities.

This provided official recognition that reading disabilities like dyslexia were due to neurological factors rather than low intelligence or poor teaching. It also helped open up access to specialized assistance and accommodations for students with dyslexia in school settings.

In 1975, the U.S. passed the Individuals with Disabilities Education Act (IDEA), which mandated public schools to provide services for students with established learning disabilities, including dyslexia. This law ensured that children with dyslexia had access to early assessment, individualized education plans, and reading support.

Modern Understanding of Dyslexia

Research over the past few decades has continued to uncover more about the underlying brain differences that cause dyslexia. Advanced brain imaging technology has allowed scientists to study neurological structure and function in much greater detail.

Studies have identified various structural brain differences associated with dyslexia. Key areas like the thalamus, cerebellum, and left temporal lobe show atypical development in individuals with dyslexia. Researchers have also pinpointed neurological connectivity patterns and functional differences that correlate with reading difficulties.

Genetic research has also found numerous gene variants associated with dyslexia, confirming reading disabilities are highly heritable. However, no single causative gene has been discovered, indicating dyslexia arises from complex interactions between multiple genetic and environmental risk factors.

Ongoing research aims to further refine our understanding of the neurobiology of dyslexia and optimize diagnostics and treatments accordingly. While much has been learned over the past century, unlocking the fundamental causes of reading disabilities remains an active area of scientific inquiry.

Evolution of Diagnosis and Definition

The methods and criteria for diagnosing dyslexia have evolved considerably over time as understanding of reading disabilities has advanced. In the past, no standardized diagnostic approach existed, leading to inconsistent and unreliable diagnoses.

Today, identifying dyslexia involves comprehensive academic, psychological, and cognitive assessments conducted by qualified professionals. Dyslexia assessment focuses on determining if an individual shows core trait like difficulty sounding out words, slow reading speed, and poor spelling that persist over time and are unexpected compared to age and abilities.

Various behavioral checklists of risk factors and early warning signs have also been developed to screen for dyslexia. While such checklists do not provide definitive diagnosis, they can identify children who need further evaluation for possible reading disabilities.

Reflecting expanding knowledge, the definition of dyslexia has been updated multiple times over decades by expert medical and educational organizations. One of the most widely accepted current definitions comes from the International Dyslexia Association:

"Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/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."

This modern definition recognizes dyslexia as a lifelong neurological condition rooted in cognitive and genetic factors, rather than a transient or environmentally created disability.

Changing Terminology

The preferred terminology used to describe dyslexia has evolved over time as understanding and attitudes have shifted. Until the latter decades of the 20th century, dyslexia was often called "word blindness" or "backwardness."

Starting in the 1960s, the term "learning disabilities" came into wide use and gradually replaced the label "mental retardation" for conditions like dyslexia unrelated to overall cognitive impairment. Using "learning disability" underscored that unexpected learning problems were not due to lack of motivation, effort, or inherent ability.

More recently, terms like "reading difference" and "Language Learning Difference (LLD)" have been proposed to highlight that dyslexia should be viewed from a difference, not deficit, perspective. However, dyslexia and Learning Disability remain the most common and widely recognized terminology.

Changing Criteria

In the past, IQ discrepancy criteria were often used to diagnose learning disabilities, including dyslexia. Children had to score significantly lower on reading tests than predicted by their general intelligence quotient (IQ) to qualify for a diagnosis.

However, in the 1990s, the use of IQ discrepancy measures began to be phased out. Research indicated that defining learning disabilities based solely on IQ scores was flawed and excluded many struggling learners from needed support services.

In their place, response to intervention (RTI) models emerged as a new process to identify children with learning disabilities. Under RTI, students receive escalating tiers of specialized instruction over time. Those who fail to progress adequately are then referred for evaluation and confirmation of disabilities.

Today, leading expert organizations emphasize using multiple criteria beyond just IQ scores or RTI results to evaluate dyslexia. Diagnosis is based on assessing cognitive abilities, academic skills, psychological processes, and familial/medical history through comprehensive testing by qualified professionals.

Conclusion

The understanding of dyslexia has grown tremendously over the past century since the first medical descriptions of unexpectedly severe and persistent reading disabilities. Dyslexia's neurological basis, genetic origins, and associated brain differences are now well established through decades of research.

Reliable, standardized methods for diagnosing dyslexia have been developed and continue improving as new knowledge comes to light. While dyslexia remains difficult to remediate in some cases, early identification and intervention greatly improves outcomes and quality of life for affected individuals.

Ongoing research promises exciting advances in unlocking the precise neurological mechanisms of dyslexia. However, much of the foundational work delineating dyslexia as a condition distinct from other learning disabilities was accomplished by pioneering doctors, psychologists and neurologists over a hundred years ago.

The history of diagnosing dyslexia reflects enormous progress made in understanding learning disabilities and helping affected children and adults. With improved awareness and support, the future looks brighter than ever for individuals with dyslexia to reach their full potential.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.