To date, most of the research on dyslexia has focused on primary school students where students are still developing literacy skills. But what if the child’s difficulties have gone unnoticed and their sweet and compliant personality is not good enough to help them breeze through high school. Let’s summarise what we do know about dyslexia and the dyslexia sub-types before we start discussing possible evidence based interventions.
The general consensus between researchers is that Dyslexia is a
“complex, biologically rooted behavioural condition resulting from impairment of reading related processes and manifested in difficulties related to the mastery of reading up to the level of population norms under the conditions of adequate education and a normal developmental environment”.
With the revision of the diagnostic manual in 2000 (Diagnostic and Statistical Handbook of Mental Disorders) came a focus on outlining learning disorders that correlate with dyslexia rather than using “dyslexia” diagnosis per se.
Under this system, we no longer diagnose students with Dyslexia but rather with Reading Disorder, Writing Disorder or both. For example, those who have difficulty acquiring age appropriate reading skills before demonstrating delays in written language and or spelling would be diagnosed with Reading Disorder. If a student then demonstrates functional reading abilities but still experiences difficulties with producing age-appropriate written work, then the diagnosis of Written Disorder would be more appropriate.
Sub-types of Dyslexia
At least three primary sub-types have been reported:
- Visual/Visual Perception,
- “Surface” dyslexia and
- “Deep” or “Phonological Dyslexia”
- Phonological Core Dyslexia.
It’s the type of dyslexia that most lay people can identify – letter and number reversals. There is some anecdotal evidence that remediation such as the introduction of “coloured glasses” can be successful but Evans in his paper on Underachieving Child (Journal of Ophthalmology Physiology and Optometric) reported that “such visual confusion, in isolation, should not be defined as dyslexia”. It has been reported by Warnke in his article on Reading and Spelling disorders: (European Child and Adolescent Psychiatry) that letter/number reversal only accounts for 5-10% of the dyslexia population.
Surface dyslexia can be described as difficulties in the use of correct orthography when reading unknown words. An orthography is the methodology of writing a language. It includes rules of spelling, hyphenation, capitalization, word breaks, emphasis, and punctuation. Children with these symptoms do not have difficulties reading “sight words” as they have learned them off by heart. As in Visual Dyslexia, this type is believed to affect only a small proportion of children that have Reading Disorders or Writing Disorder. Some believe that this form of dyslexia represents a delay in particular skill and consequently, children with these symptoms greatly benefit from Speech Pathology intervention.
This sub-type of Dyslexia has also been known as “deep dyslexia”, a condition in which reading unfamiliar and non-words is more difficult than reading familiar and irregular words. Phonological Dyslexia has been extended to become “developmental phonological dyslexia” to reflect the expectation that the dyslexia will become more apparent during the developmental period of literacy learning. This term may not be applicable to secondary students and adults as the term “developmental” may not be applicable as they are considered to beyond the literacy learning stage.
As part of the normal developmental stage of literacy learning, children learn that within words, sounds can be isolated, identified and manipulated and blended. The child is able to recognise that the words “cat” starts with the letter C but make a “k” sound and when it is replaced with “b” makes a “bat”. Some children experience difficulties grasping this concept which has been found to affect their future reading abilities. Phonological awareness deficits are quite evident in poor readers, and in later spelling abilities of adolescents and adults.
Phonological awareness deficits have also been identified in compensating adults. At present, the literature quite clearly reports that this type of dyslexia is driven by deficits in phonological awareness and is often diagnosed when reading impairments in reading are apparent in primary school-aged children. Although many primary school-aged children are now diagnosed and treated for phonological awareness deficits, a significant number of children that use compensatory techniques may enter secondary school with unidentified, unremidiated phonological awareness deficits. An additional subcategory of this type of dyslexia may be more appropriate for this population. These adolescent students and adults may be described as having Phonological Core Dyslexia, rather than Developmental Phonological Dyslexia.
The term “core” in the diagnostic marker refers to an underlying deficit in phonological skills that are accompanied by a range of written language difficulties. This subtype also acknowledges that dyslexia may not have the same characteristic in students who have moved beyond developmental stages of both written and spoken language acquisition. This is due to the fact that both adolescents and adults learn a range of compensatory strategies to overcome their difficulties.
Secondary school students with dyslexia – factors influencing diagnosis, assessment and intervention.
Development of compensatory strategies
Over time, student with Phonological Core Dyslexia may develop compensatory strategies to overcome their difficulties. However, these strategies may no longer work when capacity to compensate is exceeded by changes in learning paradigms and start to affect their motivation and self-esteem. These compensatory strategies can be self-taught or acquired from explicit instruction or direction. Students may become totally reliant on sight word reading, may use avoidance strategies or demonstrate selective reading when the complexity of preferred reading material is determined by reading abilities. Even though the use of such strategies may allow students to demonstrate basic literacy skills, there is a body of literature suggesting the degree of print literacy achieved.
There is some evidence to suggest that early reading difficulties, with reliance on sight word reading alone, may not flow-on effects on fluency and reading speed, vocabulary development and spelling abilities. Consequently, some students may present with “age appropriate” literacy skills if untimed reading comprehension is the single standard assessment and if word fluency, spelling skills are not considered.
An additional complicated issue affecting secondary school students with dyslexia is the Mathew Effect. This occurs when students who have early reading impairments read less frequently and select less complex reading material. The results can be a reduction in both the quantity and quality of the student’s exposure to age-appropriate print literature. Consequently, these students may find it difficult to keep up with their peers who experience a rich world of complex and writing styles, concepts and ideas. It is hypothesised that as a result there is a widening gap between the reading related skills of students with reading difficulties and their more literate peers. There has been mixed evidence supporting the Matthew Effect and further research is needed to see how spelling, grammatical constructs and vocabulary, as well as reading comprehension, rate and fluency may help determine the extent to which the gap and effect exist, and the type of students who are more affected.
Very slow reading rate.
A study conducted by Shaywitz and colleagues (1999) looked at adolescents who have sound reading accuracy but a very slow readers and with major deficits in their ability to spell. These students may require more time to read and to decode each word and to apply strategies to words that cannot be decoded phonologically. These difficulties may not be evident unless time pressure is factored into the assessment and possible inferences of sight words skills have been taken into account.
Research to date suggests that although secondary students with phonological core dyslexia will be able to read, they may be reliant on slower, less fluent systems and self-developed compensatory strategies to demonstrate academic performance. In this situation, difficulties may not be apparent unless the student’s phonological awareness, spelling, syntax, written language and vocabulary has been assessed.