contact us

Use the form on the right to contact us.

You can edit the text in this area, and change where the contact form on the right submits to, by entering edit mode using the modes on the bottom right.

69 Goodwood Rd
Wayville, SA, 5034

1300 66 99 40

Reading Doctor® Software is being described by educators as a breakthrough in teaching children to read and spell. Our computer software and tablet apps strengthen skills found through research to be crucial in helping students of all ages to improve their literacy skills. Teaching vital reading skills such as phonological & phonemic awareness, letter-sound knowledge, decoding and sight word recognition is easy with our unique, multi-sensory, patent pending teaching platform. Reading Doctor® Software is designed by leading speech-language pathologist and reading development expert Dr. Bartek Rajkowski, PhD. Regardless of whether you are a teacher, a reading specialist, a person learning English or a parent, we sincerely hope our programs become your favourite teaching tool!

dyslexia_exists_header.jpg

What is Dyslexia?

Dyslexia exists. Readily-available, evidence-based help for students with reading difficulties does not.

By Bartek Rajkowski, PhD.

This article is reprinted with permission from the Learning Difficulties Australia (LDA) Bulletin (Volume 48, No 3, Spring 2016). To download a PDF version of the article, please click HERE. If you are an educator or if you represent a school or other institution with an interest in the area of learning difficulties and support the principles of evidence-based practice, please consider becoming a member of the LDA. Click HERE for more information.


 

“I was a broken child. It was my mum who pursued answers and even when I was identified as dyslexic, the teachers were not convinced dyslexia was even real. It’s hard to hear that it doesn’t exist when you are living with it every day. I couldn’t read, I couldn’t spell, I couldn’t write and I was in year six.”
- Lewis, 16, student with dyslexia. 

I see kids like Lewis daily. I saw a new one recently. His name is Oliver. A week earlier, his teary mother had told me that he was causing chaos at school: uncontrollable in the classroom and constantly talking back at teachers. He had been internally suspended for a week for threatening to kill another kid. He’s nine years old. Yet, his mother says he has a heart of gold and she doesn’t know the person they are describing. She’s devastated. She feels like she’s lost her son. She doesn’t know what to do. She says his difficulties are a mystery to the school, and to her. She’s seeing a psychologist to deal with the stress. Another parent told her that Oliver might be dyslexic and that I may be able to help, but she wasn’t sure because she had also heard that dyslexia doesn’t exist.

When I first met Oliver we hit it off instantly. He was not what I’d expected based on the previous week’s description, even though I have spent 15 years helping hundreds of kids with reading difficulties. Oliver has a cheeky grin and a sense of humour as sharp as a tack. He has great language skills. We talked about how having reading and writing difficulties can make you feel stupid. I told him about what scientists have discovered: that smartness and reading skills are not closely related (Snowling & Hulme, 2011). You can be smart and struggle at school. You can also be less smart and read quickly. He smiled and raised his eyebrows. “Really?” he asked. And so we began the long journey ahead.

Over the next few sessions, Oliver enthusiastically completed his language and literacy assessment. He tried hard and concentrated well, but his assessment revealed profound literacy difficulties. The impact on his self-esteem must be devastating. After a few more sessions I became confident that Oliver has dyslexia. The alphabetic code was a total mystery to him. So what is the alphabetic code, and why is it so difficult for students like Oliver?

 

Written English: Cracking our alphabetic code

About 3000 years ago, the Phoenicians, an ancient people who lived in the area that is now the coastline of modern Lebanon, invented a radically new way of writing. In this new system, written language was represented by visual symbols that corresponded to the speech sounds, or phonemes of the language, rather than to units of meaning. This new alphabetic way of writing was a huge success and became the ancestor of almost all modern alphabetic languages, including English (Henry, 2009).

Since English is an alphabetic language, the letter patterns in the language are closely related to its phonological system. The phonological system of a language may be described as the underlying shared system of speech sounds that we use to convey meaning. Alphabetic languages rely on a process of converting this spoken, phonemic pattern into a visual, orthographic code when writing, and this code is then converted back to speech when reading.

In some alphabetic languages such as Finnish or Italian, every phoneme in the language has one corresponding grapheme (a grapheme is a letter or group of letters, such as ‘s’, or ‘oo’ in Figure 1, below). In English, however, the orthography is not quite as consistent. For example, we often keep the spelling of meaning patterns constant even when the pronunciation changes across words, like the ‘ed’ spelling of the past tense ending in ‘walked’, ‘warmed’ and ‘wanted’. English also respects the spelling patterns of other languages from which we borrow words. This all leads to variety in the way graphemes and phonemes correspond. Nevertheless, approximately 50% of English words can be spelt correctly with grapheme-phoneme conversions alone, and a further 36% of words have just one grapheme-phoneme inconsistency (Hanna, 1966). So, an understanding of the relationship between phonemes and letter patterns facilitates the “breaking of the code” in written language, since readers can work words out by sounding them out. This process is called decoding. It allows the reader to teach themselves unfamiliar words and gradually develop the accurate and automatic visual word recognition skills required for fluent reading (Share, 1999).

 
Figure 1: A hamburger analogy can help students to understand how a word, in this case ‘spoon’, may be divided into phonemes (speech sounds), graphemes (letters and groups of letters that represent speech sounds) and letters (visual symbols). Click HERE for more information.

Figure 1: A hamburger analogy can help students to understand how a word, in this case ‘spoon’, may be divided into phonemes (speech sounds), graphemes (letters and groups of letters that represent speech sounds) and letters (visual symbols). Click HERE for more information.

 

Decoding allows children to access the thousands of words they have already heard but never seen in written form. Decoding skills are crucial when reading unfamiliar regular words with consistent sound-symbol relationships (such as “representing” and “hippopotomonstrosesquippedaliophobia”) as well as non-words that consist of permissible spelling patterns but have no meaning (such as “scritten” and “borker”). Decoding skills are not as useful when reading words that contain irregular grapheme-phoneme patterns, such as “bureau”, “yacht” and “colonel”. Research, however, suggests that irregular word reading ability depends on reading experience and decoding ability (Sprenger-Charolles & Serniclaes, 2006).

 

Learning to read is not natural

Our alphabetic code is an artificial invention that is just 3000 years old. We haven’t had the time to evolve brain structures specifically for processing written language. Instead, our written language is based on our spoken language. We ‘hack’ into the brain architecture that has evolved for spoken language and thus our capacity to process written language depends on the brain’s existing language networks (Snowling & Hulme, 2011a). Eventually, the two systems become symbiotic and integrated (Snow, 2016) but initially students learning to read require specific and prolonged instruction in mastering a new visual code for the words they already understand and know how to say.

While many Australian children acquire adequate reading skills without too much difficulty, a significant proportion do not. For many of these students, weak decoding skills cause difficulty in reading unfamiliar words, and thus they do not achieve fluency and do not benefit from effective self-teaching. Furthermore, a large proportion of children with reading comprehension difficulties have those difficulties as a consequence of poor decoding ability due to inadequate instruction, dyslexia, or a combination of inadequate instruction and dyslexia (e.g., see Vellutino, Fletcher, Snowling, & Scanlon, 2004 for a review).

 

What are the characteristics of dyslexia?

“I get confust I sawnd wasds aut dut never get it rit...if il alitalpit an Barest cos ifil don’t get it rit Pepale will lavef at me.”
- Casey, 8, student with dyslexia.

Decoding difficulties and associated weaknesses in visual word recognition are primary indicators of dyslexia (See Figure 2, below, for a full definition). These difficulties are often unexpected given the student’s age and other cognitive abilities, and are not caused by sensory processing issues such as poor eyesight or hearing loss. Historically, definitions of dyslexia relied on a discrepancy between IQ and reading ability; however more recent research shows that an IQ test is not required to identify dyslexia, and that dyslexia occurs across a range of intellectual abilities (e.g., Tanaka et al., 2011). Children with dyslexia struggle to form accurate, automatic letter - sound associations. They find decoding very difficult and effortful, even if high quality, evidence-based methods of teaching are employed in the classroom and practised during individual tutoring.

 
Figure 2: Summary of International Dyslexia Association definition of dyslexia (IDA, 2002).

Figure 2: Summary of International Dyslexia Association definition of dyslexia (IDA, 2002).

 

Students with dyslexia often struggle with developing reading fluency and reading comprehension, and spelling can be particularly difficult. They may have severe literacy difficulties despite having many cognitive strengths and despite a language-rich home environment in which they are read to every night. These difficulties can be extremely confusing, frustrating and heart-breaking for the students, their parents and their teachers.

 

Incidence of Dyslexia

Dyslexia does not have any clear ‘cut-off’ points, meaning that it is not a distinct category. It is best thought of as a term referring to the lower end of a continuum of reading ability, in the same way that the term ‘hypertension’ describes blood pressure that is at the highest end of the measurement scale. For this reason, there is some variation in the reported incidence of dyslexia. For example, one large US study found that reading disability affects one in five children (Shaywitz, 2003), while the Australian Dyslexia Working Party estimates that dyslexia will affect 5-10% of children, making learning to read very difficult for them even if their teachers use sound, evidence-based teaching methods (Bond et al., 2009).

bartek_dyslexia

Dyslexia exists in all languages, although the complications of English orthography make decoding particularly challenging. Reading difficulties in consistent orthographies and in logographic systems (such as Chinese) are characterised more by fluency problems than by accuracy problems (Peterson & Pennington, 2012). Although there is variation in how dyslexia manifests itself across languages, the underlying causes of dyslexia appear to be universal (Ziegler & Goswami, 2005).

 

 

Dyslexia and Phonological Processing Skills

So what causes these often unexpected difficulties? Dyslexia runs in families, suggesting a strong genetic component (Hulme & Snowling, 2016). An extensive body of behavioural and neuro-imaging evidence suggests that the core deficit in dyslexia is impairment in phonological processing skills, which makes it more difficult to map the written representations of the language onto its sound structure. This results in poor decoding, poor self-teaching and thus poor reading ability (Share, 1995). Researchers have discovered three main phonological processing tasks which are believed to tap into the underlying phonological processing deficits in individuals with dyslexia.

Phonological awareness is an umbrella term referring to the ability to identify, reflect upon and manipulate the sounds of language at any of its various levels of representation, including skills such as rhyming words or counting syllables. Phonemic awareness, a sub-skill of phonological awareness that reflects understanding of and ability to manipulate individual phonemes in words, seems to give children a significant advantage in learning to read the printed form of language (Wagner, Torgesen, & Rashotte, 1999). Phonemic awareness is a powerful and early predictor of individual differences in reading development (Melby-Lervåg, Lyster, & Hulme, 2012) and phonemic awareness difficulties are a hallmark of dyslexia.

Scientists have discovered that many individuals with dyslexia also have slower verbal processing speed, as assessed through rapid automatic naming (RAN) tasks. RAN tasks require individuals to name a series of objects, colours, numbers or letters as quickly as possible. Difficulties with RAN are thought to reflect inefficiencies in the process of retrieving a phonological form that corresponds to a visual stimulus. RAN performance is correlated with reading ability and is a strong predictor of future reading skills in pre-literate children (Lervåg & Hulme, 2009). Deficits in both RAN and phonemic awareness lead to more severe reading impairments than a deficit in phonemic awareness or RAN alone (e.g., Wolf et al., 2002; Wolf & Bowers, 1999).

Many individuals with dyslexia also show weaker phonological memory, reflecting a reduced ability to recall what was just said (e.g., Jeffries & Everatt, 2004). Phonological memory has been shown to be integral to vocabulary acquisition and is an important sub-skill in many aspects of reading, such as remembering the sounds when sounding out unfamiliar words (Wang & Gathercole, 2013).

Children with dyslexia experience ongoing difficulties with phonological processing throughout their lives, and these difficulties appear to be responsible for a significant disadvantage in learning to read print (Hulme & Snowling, 2016).

 

What causes phonological processing problems?

The “phonological deficit hypothesis” posits that phonological processing tasks depend upon the strength of phonological representations: the brain’s representations of the sound structure of language (e.g., Thomson & Goswami, 2009; Snowling, Bishop, & Stothard, 2000). These phonological representations are thought to be weaker, or ‘less specific’, in individuals with dyslexia.

The precise nature of the phonological deficit in dyslexia is an area of intensive, ongoing research. Since the phonological system becomes increasingly sensitive to phonemic differences between words as vocabulary size grows (Ziegler & Goswami, 2005), a close relationship is thought to exist between vocabulary acquisition and phonological processing. A sub-group of individuals with dyslexia may have speech perception deficits (e.g., Adlard & Hazan, 1998), or poorer speech perception in noise (e.g., Ziegler, Pech-Georgel, George, & Lorenzi, 2009), and speech perception measures at infancy are predictive of later reading acquisition (e.g., Lyytinen et al., 2004). Other studies have suggested that phonological processing difficulties in dyslexia may be related to short-term memory processes operating on phonological representations, rather than impaired phonological representations as such (Ramus, 2014). While many questions remain, further research will likely provide better explanations and interventions for the phonological processing deficit in individuals with dyslexia.

 

Children with dyslexia may also have other difficulties

Comprehension is the goal of reading. According to the ‘simple view’ of reading proposed by Gough and Tunmer (1986), reading is the product of decoding and language comprehension. In other words, being a good reader depends on both strong decoding skills and strong language skills. If either skill is weak, the individual will experience reading difficulties.

Language deficits are common in individuals with dyslexia. For example, Eisenmajer, Ross and Pratt (2005) found that 53% of 151 children assessed for learning disabilities demonstrated both reading and oral language difficulties. These children showed significantly more impaired phonological processing and spelling skills than the children with either language or reading difficulties. The evidence suggests that although dyslexia and specific language impairment (SLI) frequently co-occur, they are distinct disorders, as shown in Figure 3 (Ramus, Marshall, Rosen, & Lely, 2013).The frequent co-occurrence of dyslexia and language impairment is likely to be the result of phonological deficits that are common to both specific language impairment (SLI) and dyslexia (Snowling, 2009).

 
Figure 3: Relationship between dyslexia and specific language impairment (SLI) (Ramus et al., 2013).

Figure 3: Relationship between dyslexia and specific language impairment (SLI) (Ramus et al., 2013).

 

 

Another difficulty that often co-occurs with SLI and dyslexia is a history of speech sound difficulties, or problems in pronouncing words clearly. There is mounting evidence for a link between dyslexia and articulation difficulties (Pennington, 2006). Articulatory difficulties may interfere with the development of phonemic awareness and grapheme-phoneme associations (e.g., Lalain, Joly-Pottuz, Nguyen & Habib, 2003; Snowling, 2009). Children whose articulation difficulties are unusual, severe, or persistent are particularly at risk (e.g., Nathan, Stackhouse, Goulandris, & Snowling, 2004).

Children with dyslexia may also have attention problems. Between 25% and 40% of children with either dyslexia or attention deficit hyperactivity disorder (ADHD) would also qualify for a diagnosis of the other disorder (Pennington, 2006). Finally, the fact that written language is a visual code had led researchers to investigate possible visual processing deficits in dyslexia. However, a joint policy statement issued by the American Academy of Pediatrics (2009) concluded that “… subtle eye or visual problems, including visual perceptual disorders, refractive error, abnormal focusing, jerky eye movements, binocular dysfunction or crossed eyes, do not cause dyslexia” (p. 839).

 

How can we help kids with dyslexia and other reading difficulties?

“...There are children and adults who have dyslexia but were never lucky enough to be diagnosed. To have something to blame. They will know something is wrong and isn’t right with them, because they are not stupid or pathetic or a waste of space or inadequate but they will believe they are...”
- Eliza, 17, student with dyslexia.

The alphabetic code is a mystery to Oliver, the student I mentioned at the beginning of this article, because he has dyslexia. That means he needs a lot of help in creating associations between graphemes and phonemes so he can learn to decode and read fluently. He’s not ‘dumb’: far from it. His profile suggests he has tremendous potential for improvement: despite severely impaired overall reading ability, decoding, phonemic awareness, grapheme knowledge and spelling, he has excellent non-phonological language skills. His RAN and phonological memory are also relatively strong. He concentrates well and is motivated to improve, and has a very caring and supportive family. There are no quick fixes or guarantees, only a long course of intensive work on core skills, but I regularly see students like him make significant and important progress. Just this morning, I received a text from a student whom I first saw at the age of eight who also had profound literacy difficulties. After many years of regular, intensive help, she’s about to complete a double degree in teaching and special education.

 
 

 

What remains a mystery to me is this: How can a kid like Oliver come so close to disaster and not receive the type of assistance that research (and my own clinical experience) shows will make a tremendous difference to his life? Why are Oliver’s difficulties misunderstood by his very caring and well-meaning teachers?

There is no question that every teacher wants to ensure the best possible outcomes for their students. The blame does not lie with Oliver’s teachers or his school. The problem seems to be that very few teachers are aware of the extensive research on literacy development, literacy difficulties and dyslexia. Even fewer have received training in the evidence-based teaching of reading. In my experience with running training workshops on this topic for teachers around Australia, teachers are desperate for more information and training on helping our students with reading development. Until we improve teacher training, millions of Australian students with reading disorders, as well as their parents and their teachers, will continue to believe that their difficulties are a mystery or, worse, a result of a lack of intelligence. Oliver needs urgent, intensive, ongoing and individualised explicit instruction to help him to read and spell. I hate telling his mother that it is highly unlikely he will get that kind of help at school.

Many of Australia’s leading researchers, speech-language pathologists and psychologists have spent years unsuccessfully urging our education system to align itself with research recommendations. Three important facts need noting:

  1. Australia is failing to equip its increasingly frustrated and well-meaning workforce of dedicated teachers with the skills required to teach reading and spelling effectively (Buckingham, Wheldall, & Beaman-Wheldall, 2013);
  2. Australia has so far failed to follow the recommendations of three major inquiries into the teaching of literacy, each of which strongly supported explicit, systematic, evidence-based instruction in the ‘big five’ literacy skills: phonemic awareness, phonics, fluency, vocabulary and comprehension (http://www. fivefromfive.org.au/); and
  3. we are especially poor at providing intensive and explicit instruction in the very skills that fail to develop most often in our poorest readers: phonemic awareness and decoding ability. Teaching these skills should be ‘bread and butter’ for all teachers: research shows that all students benefit most from reading lessons that explicitly teach students about the relationship between phonology and orthography in language, helping them to ‘break the code’ and master self-teaching (Rowe, 2006)

Finally, it’s crucial that discussions about the usefulness of the term ‘dyslexia’ don’t obscure the fact that an unacceptable number of Australian children are failing to develop adequate literacy skills (Castles, Wheldall, & Nayton, 2014). Dyslexia, as identified by decades of careful, well-replicated scientific research, definitely exists. What doesn’t yet exist is widely available, effective, evidence-based help for Australian students with reading difficulties.

 


This article is reprinted with permission from the Learning Difficulties Australia (LDA) Bulletin (Volume 48, No 3, Spring 2016). To download a PDF version of the article, please click HERE. Learning Difficulties Australia is an association of teachers and other professionals dedicated to assisting students with learning difficulties through effective teaching practices based on scientific research, both in the classroom and through individualised instruction (click HERE for more information).



 

References

Quotes are extracts from “Red Letters” written or spoken by children with dyslexia. For full versions of the letters, see www.myredletter.com.au

Adlard, & Hazan, V. (1998). Speech perception in children with specific reading difficulties (dyslexia). Quarterly Journal of Experimental Psychology, 51(1), 153–177. American Academy of Pediatrics. (2009). Learning disabilities, dyslexia, and vision. Pediatrics, 124(2), 837–844.

Banai, K., Hornickel, J., Skoe, E., Nicol, T., Zecker, S., & Kraus, N. (2009). Reading and subcortical auditory function. Cerebral Cortex, 19(11), 2699– 2707.

Bond, J., Coltheart, M., Connell, T., Firth, N., Hardy, M., Nayton, M., … Weeks, A. (2009). Helping people with dyslexia: A national action agenda.

Buckingham, J., Wheldall, K., & Beaman-Wheldall, R. (2013). Why Jaydon can’t read: The triumph of ideology over evidence in teaching reading.

Castles, A., Wheldall, K., & Nayton, M. (2014). Should we do away with “dyslexia”?

Eisenmajer, N., Ross, N., & Pratt, C. (2005). Specificity and characteristics of learning disabilities. Journal of Child Psychology and Psychiatry, 46(10), 1108–1115. Gough, P. B., & Tunmer, W. E. (1986). Decoding, reading, and reading disability. Remedial and Special Education, 7(1), 6–10.

Hanna, P. R. (1966). Phoneme-grapheme correspondences as cues to spelling improvement. U.S. Dept. of Health, Education, and Welfare, Office of Education.

Henry, M. (2009). Words: Integrated decoding and spelling instruction based on word origin and word structure (2nd ed.). Pro-ed.

Hulme, C., & Snowling, M. J. (2016). Reading disorders and dyslexia. Current Opinion in Pediatrics. 

Jeffries, S., & Everatt, J. (2004). Working memory: Its role in dyslexia and other specific learning difficulties. Dyslexia, 10(3), 196–214. 

Lalain, M., Joly-Pottuz, B., Nguyen, N., & Habib, M. (2003). Dyslexia: The articulatory hypothesis revisited. Brain and Cognition, 53(2), 253–256.

Lyytinen, H., Ahonen, T., Eklund, K., Guttorm, T., Kulju, P., Laakso, M.,Viholainen, H. (2004). Early development of children at familial risk for Dyslexia—follow-up from birth to school age. Dyslexia, 10(3), 146–178.

Melby-Lervåg, M., Lyster, S.-A. H., & Hulme, C. (2012). Phonological skills and their role in learning to read: A meta-analytic review. Psychological Bulletin, 138(2), 322–352.

Nathan, L., Stackhouse, J., Goulandris, N., & Snowling, M. J. (2004). The development of early literacy skills among children with speech difficulties: A test of the “critical age hypothesis.” Journal of Speech Language and Hearing Research, 47(2), 377–391.

Pennington, B. F. (2006). From single to multiple deficit models of developmental disorders. Cognition, 101(2), 385–413. Peterson, R. L., & Pennington, B. F. (2012). Developmental dyslexia. The Lancet, 379(9830), 1997–2007. Ramus, F. (2014). Neuroimaging sheds new light on the phonological deficit in dyslexia. Trends in Cognitive Sciences, 18(6), 274–275.

Ramus, F., Marshall, C. R., Rosen, S., & Lely, H. K. J. van der. (2013). Phonological deficits in specific language impairment and developmental dyslexia: towards a multidimensional model. Brain, 136(2), 630–645.

Rowe, K. (2006). Teaching reading: Findings from the National Inquiry. Research Developments, 15(15).

Share, D. L. (1995). Phonological recoding and self-teaching: Sine qua non of reading acquisition. Cognition, 55(2), 151-218-226. Share, D. L. (1999). Phonological recoding and orthographic learning: A direct test of the self-teaching hypothesis. Journal of Experimental Child Psychology, 72(2), 95–129.

Shaywitz, S. E. (2003). Overcoming dyslexia: A new and complete sciencebased program for reading problems at any level. New York: A.A. Knopf.

Snow, P. C. (2016). Elizabeth Usher Memorial Lecture: Language is literacy is language - Positioning speech-language pathology in education policy, practice, paradigms and polemics. International Journal of SpeechLanguage Pathology, 0(0), 1–13.

Snowling, M. J. (2009). Changing concepts of dyslexia: Nature, treatment and comorbidity. Journal of Child Psychology and Psychiatry.

Snowling, M. J., Bishop, D. V. M., & Stothard, S. E. (2000). Is preschool language impairment a risk factor for dyslexia in adolescence? Journal of Child Psychology and Psychiatry, 41(5), 587–600.

Snowling, M. J., & Hulme, C. (2011a). Annual Research Review: The nature and classification of reading disorders: A commentary on proposals for DSM 5. Journal of Child Psychology and Psychiatry. 

Snowling, M. J., & Hulme, C. (2011b). Evidence-based interventions for reading and language difficulties: Creating a virtuous circle. British Journal of Educational Psychology, 81(1), 1–23.

Sprenger-Charolles, L., & Serniclaes, W. (2006). Reliability of phonological and surface subtypes in developmental dyslexia: A review of five multiple cases studies. Current Psychology Letters, (10, NaN, 2003).

Tanaka, H., Black, J. M., Hulme, C., Stanley, L. M., Kesler, S. R., Whitfield-Gabrieli, S., … Hoeft, F. (2011). The brain basis of the phonological deficit in dyslexia is independent of IQ. Psychological Science.

Thomson, J., & Goswami, U. (2009). Learning novel phonological representations in developmental dyslexia: associations with basic auditory processing of rise time and phonological awareness. Reading and Writing, 23(5), 453–473.

Vellutino, F. R., Fletcher, J. M., Snowling, M. J., & Scanlon, D. M. (2004). Specific reading disability (dyslexia): What have we learned in the past four decades? Journal of Child Psychology and Psychiatry, 45(1), 2–40.

Wagner, R. K., Torgesen, J. K., & Rashotte, C. A. (1999). CTOPP: Comprehensive Test of Phonological Processing. Austin, TX: PRO-ED.

Wang, S., & Gathercole, S. E. (2013). Working memory deficits in children with reading difficulties: Memory span and dual task coordination. Journal of Experimental Child Psychology, 115(1), 188–197.

Willcutt, E. G., Betjemann, R. S., McGrath, L. M., Chhabildas, N. A., Olson, R. K., DeFries, J. C., & Pennington, B. F. (2010). Etiology and neuropsychology of comorbidity between RD and ADHD: The case for multiple-deficit models. Cortex, 46(10), 1345–1361.

Wolf, M., & Bowers, P. G. (1999). The double-deficit hypothesis for the developmental dyslexias. Journal of Educational Psychology, 91(3), 415– 438.

Wolf, M., O’Rourke, A. G., Gidney, C., Lovett, M., Cirino, P., & Morris, R. (2002). The second deficit: an investigation of the independence of phonological and naming-speed deficits in developmental dyslexia. Reading and Writing: An Interdisciplinary Journal, 15(1–2), 43–72.

Ziegler, J. C., & Goswami, U. (2005). Reading acquisition, developmental dyslexia, and skilled reading across languages: A psycholinguistic grain size theory. Psychological Bulletin, 131(1), 3–29.

Ziegler, J. C., Pech-Georgel, C., George, F., & Lorenzi, C. (2009). Speech-perception-in-noise deficits in dyslexia. Developmental Science, 12(5), 732–745.