specific learning disabilities: medical and historical perspectives

Specific Learning Disabilities:Medical and Historical Perspectives

DyslexiaAudio Processing DysfunctionVideo Processing Dysfunction

What is an SLD?

• Defined by IDEA as “a condition within the individual affecting learning relative to potential.”

• A neurological disorder resulting from the “difference in the way a person’s brain is wired.” –LD Online (2008)

• A learning disability can't be cured or fixed; it is a lifelong issue.

What is an SLD? (cont’d)

• Children with learning disabilities are often as intelligent or more so than their peers, but may have difficulty reading, writing, spelling, or organizing information because of interference in the acquisition process when taught by conventional methods.

What is an SLD? (cont’d)

• SLDs result in a discrepancy between a child’s ability and his/her academic performance in one or more of these areas:– Oral expression– Listening comprehension– Mathematical calculation and reasoning– Basic reading skills and comprehension– Written expression

What is an SLD? (cont’d)• Aside from academic performance, SLDs can

also affect self-esteem, career development, life-adjustment skills.

• SLDs may occur with but are not primarily the result of the following:– Visual, hearing, motor, or mental impairment– Emotional disorder– Environmental, cultural, or economic influence– History of inconsistent education program

(Maanum, 2009)

Dyslexia

What is Dyslexia?

• Dyslexia is defined by the International Dyslexia Association (2000) as a “language-based disability in which a person has trouble understanding words, sentences or paragraphs; both oral and written language are affected.”

• An earlier definition, formulated by a dyslexia research committee with the National Institutes of Health added that the disorder was “characterized by difficulties in single word decoding, usually reflecting insufficient phonological processing abilities” that are “often unexpected in relation to age and other cognitive and academic abilities” (Shaywitz, Fletcher & Shaywitz, 1994).

What is Dyslexia?• Both of these definitions describe children with disabilities

in the processing and acquisition of language, despite normal intelligence, normal hearing, normal vision, no known neurological impairments or deficits, and appropriate educational opportunities.

• It is referred to as a learning disability because dyslexia can make it very difficult for a student to succeed academically in the typical instructional environment, and in its more severe forms, will qualify a student for special education, special accommodations, or extra support services.

A Brief History

• It was not until the publication of the government document, The Code of Practice (Department for Education and Employment, 1994) that dyslexia was given official recognition.

• The term dyslexia did not come into general use until the late twentieth century.

• Before the twentieth century, children who had literacy difficulties were largely considered to have medical problems, or were constitutionally limited or poorly motivated.

A Brief History (cont’d)• Societal interest in people with reading difficulties probably

began in 1878 with Adolph Kussmaul, a German neurologist. He had a special interest in adults with reading problems who also had neurological impairment. He noticed that several of his patients could not read properly and regularly used words in the wrong order. He introduced the term ‘word blindness’ to describe their difficulties. The phrase, word blindness, then began to be used regularly in the medical journals to describe adults and children who had difficulty learning to read. This phrase also conveyed the fact that these patients were neurologically impaired.

A Brief History (cont’d)

• In 1887, a German ophthalmologist, Rudolf Berlin, was the first to use the word ‘dyslexia’ in place of word blindness. However, the term of dyslexia did not come into common usage in the literature until the following century. Before then word blindness was more commonly used to describe this group of adults and children with reading problems.


• The next milestone in the history of dyslexia appeared in 1891 with a report in The Lancet medical journal by Dr Dejerne. This report described a patient who had suffered a brain injury after having been hit on the head with a crowbar. The patient had lost several language functions, including the ability to read. A medical hypothesis then emerged that concluded that those who had difficulty reading had probably suffered a brain injury.


• In 1900, Dr James Hinshelwood, a Scottish eye surgeon, published an account of a patient who had reading difficulties and also a congenital defect in the brain related to eyesight. From this evidence he concluded that the cause of reading difficulties was a malfunction of eyesight as a result of a brain defect. Dr Hinshelwood’s work rein- forced the use of the term word blindness and this phrase persisted throughout the early twentieth century.


• In 1925 Dr. Orton, an American neurologist, was probably the first to recognize that children with reading difficulties often reversed letters. This phenomenon he called “strephosymbolia.” He also introduced the term “developmental alexia” to describe these children with reading difficulties. There were now three different terms in existence, all used to describe this learning difficulty.


• It was not until the mid-1930s that the term dyslexia began to more commonly appear in the literature. The word dyslexia is of Greek origin and combines ‘dys’, meaning an absence, and ‘lexia’, meaning language. So, literally, the word dyslexia means an absence of language. Learning difficulties, especially dyslexia, were now beginning to be viewed primarily as educational problems.


• A significant event in the history of dyslexia occurred in 1963 when the Invalid Children’s Aid Association (ICAA) established the Word Blind Centre for Dyslexic Children in London. Its main aim was to provide a center for the teaching of dyslexic children, and it was one of the first institutions to conduct research into the causes of dyslexia.


• A much-needed publicity boost for dyslexic children occurred in 1967 with the establishment in the USA of the Orton Dyslexia Society. This organization was mainly responsible for the subsequent increase in public and political attention given to the needs of dyslexic children in the USA. The Society’s influence gradually extended beyond the USA, so that in 1997 it changed its name to the more appropriate title International Dyslexia Association, a title it holds today.

A Brief History (cont’d)• Up to the early and late twentieth century, school

medical officers had been conducting the assessment of children with learning difficulties using intelligence tests devised by psychologists. It was not until the 1970s that medicine relinquished its role in that sphere and the assignment of intelligence testing was given to the educational psychologists. After publication of the Warnock Report (1978), it became inappropriate for these medical officers to be responsible for intelligence testing and also for the administrative categorization of children with learning difficulties.


• Dyslexia had always been researched as a deficit with research into various cognitive weaknesses and neurological deficits. However, in the early 1980s, a new notion began to emerge that seemed to be about to revolutionize the thinking on dyslexia. This notion was that dyslexia might be a difference and not a deficit after all.

A Brief History (cont’d)• The view that dyslexia might be a different way of learning

probably began with the work of Gardner (1983) with his theory of multiple intelligences.

• The work of Galaburda (1989) with adults gave further support to the view proposed by Gardner. It was while performing autopsies that Galaburda noticed that there was a superior development of the right hemisphere in those who had been diagnosed as dyslexic. The right hemisphere is the part of the brain that was said to be concerned more with creativity and visual processing. The corollary to this was that dyslexic people were likely to be more creative and to use a more visual approach to learning. Galaburda offered the view that perhaps dyslexia was a normal variation of the development of the brain and not necessarily a disorder.


• The hypothesis that dyslexia is a different way of learning and not necessarily a deficit gained further publicity at this time with authors such as Silverman (2002) and Freed (1997). Silverman and Freed demonstrated how dyslexic children made excellent progress in literacy skills with programs specifically designed to develop the facility that began to be termed ‘visual spatial thinking.’


• The notion that dyslexia was a different way of learning was supported by West (1997). West proffered the view that dyslexic children were ‘visual thinkers’ and additionally showed unusual creativity, as had been suggested by Gardner (1983). More recently, Stahl (2002) highlighted the fact that most dyslexic children tend to use a more visual learning style.

Current Perspectives

• The topic of dyslexia seems now to have come full circle from its early beginnings when dyslexia used to be regarded wholly as a medical problem. Today, the medical profession, educationalists and psychologists are all collaborating in a search for the origins and treatment of dyslexia. One example of the results of this collaboration is the research that has taken place establishing the relationship between the neurology of the brain and dyslexia.

Current Perspectives (cont’d)

• New technology has allowed research to focus on specific parts of the brain that are activated in learning so that it is now possible to localize different brain functions and to observe the extent of their differences in activation. This development came about with the invention of functional magnetic resonance imaging (fMRI) and also the positron emission tomography (PET). These machines have provided research workers with techniques that have increased our knowledge of brain functioning in general.

Current Perspectives (cont’d)

• Most of the research into dyslexia is now being conducted within the spheres of psychology and education. It is doubtful whether the study of dyslexia will ever return to the early days when it was considered to be wholly in the sphere of medicine. Whatever the future research discoveries regarding the biological and neurological origins of dyslexia, it is almost certain that the help offered to children with dyslexia will continue to be in the realm of education.

What Causes Dyslexia?• The exact causes of dyslexia are still not completely clear,

but anatomical and brain image studies show differences in the way the brain of a dyslexic person develops and functions. Moreover, people with dyslexia have been found to have problems identifying speech sounds in words and how letters represent them. Dyslexia is not due to either lack of intelligence or a desire to learn; with appropriate teaching methods, most dyslexics can learn successfully. It is known that dyslexia is heritable, and therefore, it is not uncommon to have multiple members of the same family with reading problems.

How Widespread is Dyslexia?

• Although research is ongoing and some results vary, the National Institutes of Health and other reputable agencies estimate that between 4-15% of the men, women, and children in this country are dyslexic. Dyslexia occurs in people of all backgrounds and intellectual levels. Some people are identified as dyslexic early in their lives, but for others their dyslexia goes unidentified until they get older.

How is Dyslexia Diagnosed?

• A formal evaluation is needed to determine if a person is dyslexic. The evaluation assesses intellectual ability, information processing, psycho-linguistic processing, and academic skills.

• Schools may use a new process called Response to Intervention (RTI) to identify children with learning disabilities. Under an RTI model, schools provide those children not readily progressing with the acquisition of critical early literacy skills with intensive and individualized supplemental reading instruction.

How is Dyslexia Treated?• Dyslexia is a life-long condition. With proper help people with

dyslexia can learn to read and/or write. Early identification and treatment is the key to helping dyslexics achieve in school and life. Most people with dyslexia need help from a teacher, tutor, or therapist specially trained in using a multi-sensory, structured approach. It is important for these individuals to be taught by a method that involves several senses (hearing, seeing, touching) at the same time. Many individuals with dyslexia need one-on-one help so that they can move forward at their own pace. For students with dyslexia, it is helpful if their outside academic therapists work closely with classroom teachers.

Audio Processing Dysfunction (APD)

What is APD?

• Children who have difficulty using information they hear in academic and social situations may have auditory processing disorder (APD). These children typically can hear information but have difficulty attending to, storing, locating, retrieving, and/or clarifying that information to make it useful for academic and social purposes (Katz & Wilde, 1994). This can have a negative impact on both language acquisition and academic performance.

What is APD? (cont’d)• APD is an impaired ability to attend to, discriminate,

remember, recognize, or comprehend information presented auditorily in individuals who typically exhibit normal intelligence and normal hearing (Keith, 1995). This definition has been expanded to include the effects that peripheral hearing loss may contribute to auditory processing deficits (Jerger & Musiek, 2000). Auditory processing difficulties become more pronounced in challenging listening situations, such as noisy backgrounds or poor acoustic environments, great distances from the speaker, speakers with fast speaking rates, or speakers with foreign accents (Sloan, 1998).

How is APD Diagnosed?• The diagnosis of APD remains controversial, largely

because of the purported co-morbidity with associated conditions such as attention-deficit/hyperactivity disorder, other learning disabilities, and speech-language impairment, as well as the diversity of signs and symptoms associated with this disorder. Some of the more common diagnostic tests for APD include Staggered Spondaic Word (SSW) Test, the SCAN Screening Test for auditory processing disorders, and the Multiple Auditory Processing Assessment (MAPA). There is no clear acceptance of a "gold standard" test battery for evaluating this disorder.

What are the Causes of APD?

• The specific causes of APD are unclear, however, it does not appear to be caused by peripheral hearing impairment. In children, auditory processing difficulty may be associated with conditions such as dyslexia, attention deficit disorder, autism, autism spectrum disorder, specific language impairment, pervasive developmental disorder, or developmental delay. Sometimes this term has been misapplied to children who have no hearing or language disorder but have challenges in learning.

APD and ADHD

• The behaviors of children with APD and ADHD may be very similar, especially with regard to distractibility. Given what is presently known, APD and ADHD do not appear to be a single developmental disorder. Each can occur independently, or they can coexist. This is a prime example of where the team approach to evaluation is critical, as the team can rule out the presence of ADHD or determine its contribution to the potential educational impact on the child.

How is APD Treated?

• There are no established therapies for the treatment of patients with APD. Current approaches include signal enhancement, linguistic and cognitive strategies, auditory training (including auditory integration therapy), as well as medication. Signal enhancement strategies aim to improve the signal to noise ratio. This can be achieved by minimizing background noise or by using frequency-modulated systems in the classroom. Linguistic and cognitive strategies aim to increase use of compensatory strategies.

How is APD Treated? (cont’d)

• Methylphenidate (Ritalin), a drug traditionally prescribed for the management of patients with attention deficit/hyperactivity disorder (ADHD), has been used to treat children with APD. However, it is unclear whether methylphenidate can improve auditory processing, thus, methylphenidate and related stimulant medications should not be prescribed routinely for treatment of APD in the absence of ADHD.

How is APD Treated? (cont’d)

• Given the problems associated with diagnosing APD, any therapies should be viewed cautiously. The National Institute on Deafness and Other Communication Disorders (2001) stated that it is important to know that much research is still needed to understand auditory processing problems, related disorders, and the best interventions for each child or adult.

Visual Processing Dysfunction

What is Video Processing Dysfunction?

• Visual Processing Dysfunction is the inability for an individual to make proper sense of information taken in through the eyes. This disorder has nothing to do with one's vision or the sharpness of it, but it is the difficulties experienced with how visual information is processed by the sufferer's brain. The individual may have 20/20 vision but may have problems in figuring out background from foreground, size, forms and positions in space.

Visual Processing Dysfunction Interventions

• Typically, interventions involve daily eye exercises, work with specific computer programs, Neurotherapy, physical games and activities, and academic adjustments. The behavioural optometrist will make recommendations for optometric exercises and the Behavioural Neurotherapy Clinic may recommend Nutrient Supplements and/or Neurotherapy protocols to retrain relevant brain areas associated with visual processing that are identified through Brainmapping as having less than optimum function.