Shifts in the understanding: A good source for basic information is “Dyslexia at a Glance,” International Dyslexia Association.
combination of a high-interest topic: Researcher Dorothy Bishop on how to distinguish credible interventions from quackery: “Pioneering Treatment or Quackery? How to Decide,” BishopBlog, December 4, 2011, http://goo.gl/UfC1JJ. Her blog is an exceptionally good, highly recommended source of information on developmental disorders and many other topics.
For example, impaired phonological processing: Pennington & Bishop (2009) is an excellent review.
Definitions vary: See Fletcher (2009) for a history of the concept of dyslexia.
American Academy of Pediatrics provides guidelines: The American Academy of Pediatrics (2009) statement is also very clear about why vision problems are rarely the cause of dyslexia. “Learning Disabilities, Dyslexia, and Vision,” Pediatrics 124, no. 2 (August 2009).
definitions used in such legislation: On IDEA language, see “Topic: Identification of Specific Learning Disabilities,” ED.gov, http://goo.gl/L9bTjs.
It defines a general category: For an explanation of the DSM-5 categorization scheme, see Rosemary Tannock, “DSM-5 Changes in Diagnostic Criteria for Specific Learning Disabilities (SLD)1: What Are the Implications?,” International Dyslexia Association, https://eida.org/dsm5-update.
Researchers have their own accounts: Thomas Insel, former director of the National Institute for Mental Health (NIMH), launched an initiative to replace the DSM with a new classification system based on behavioral, neural, and genetic data. As yet there isn’t sufficient evidence to sort conditions on these bases, however. See Thomas Insel, “Director’s Blog: Transforming Diagnosis,” NIMH, April 29, 2013, http://goo.gl/3oNVfY).
children have spoken-language impairments: Dyslexia is far more common than comprehension disorder. Very few children who have good basic skills fail to comprehend. When this occurs, the first question is whether the child can understand the text if it is read to them. Instructional and motivational issues aside, comprehension deficits are not limited to reading. The extreme example is hyperlexia, a rare condition seen in some children on the autism spectrum for whom reading words aloud is their area of specialized expertise, but their comprehension of the same words is poor. Good decoding with poor comprehension also occurs in some children with developmental language impairments. See Snowling & Frith (1986) and Snowling (2013).
World Federation of Neurology defined dyslexia: Critchley (1970).
The US Department of Education definitions: The history is in Hammill et al. (1988).
Reading ability and intelligence fall: US Office of Education (1977). On the IQ discrepancy criterion, see Fletcher (2009).
inherent arbitrariness of the boundary: Keith Stanovich conducted the critical research on the flaws in the IQ discrepancy criterion. See Stanovich (2005).
The cutoffs were initially set: The logic here is similar to the focus on the relatively rare cases of brain-injured patients with highly selective impairments in neuropsychology.
The heritability of a trait: The discussion of height in Lai (2006) is helpful.
The use of discrepancies: Stanovich (2005); Fletcher (2009).
These correlations are modest: Peterson & Pennington (2012).
Patterns of brain activity: Tanaka et al. (2011).
The primary question: The IQ discrepancy criterion was flawed because it excluded lower-IQ children whose reading was indistinguishable from that of higher-IQ dyslexics. Dyslexia is now more often defined by the discrepancy between the child’s reading level and what is expected for their age or grade. Bruce Pennington, a distinguished figure in this field, has pointed out that this procedure will overlook high-IQ children whose reading is within the normal range but below what might be expected given their intelligence. Children with this type of discrepancy may well merit additional attention at school, which could easily be overlooked. However, given their level of reading skill, categorizing these children as “dyslexic” would probably create further confusion because the category would no longer be limited to children who read poorly.
individuals can be studied: Pennington & Lefly (2001). A bump appears at the low end of the distribution if such children are included.
dyslexia is the purposeful: As trenchantly expressed to me by Judith Levine.
boundary between having: Also paralleling dyslexia, changes in the criteria for identifying hypertension have created controversy; see James et al. (2014); Candy Sagon, “New Blood Pressure Guidelines Draw Fire,” AARP Bulletin, March 2014, http://goo.gl/RGDZGx.
“There is no such thing”: Arin Gencer, “National Reading Expert Comes to Baltimore County,” Baltimore Sun, February 13, 2009, http://goo.gl/L8Dp2t. Also: “I don’t happen to believe that dyslexia or learning disabilities exist, dyspedagogia yes, but not the mythological dyslexia.” Anthony Rebora, “Responding to RTI,” Education Week, April 9, 2010, http://goo.gl/mIBQ8M.
Some of the biggest excuses: Lindsay Fiori, “Getting Children to Read Books Must Supersede Disinterest, Limited Funding, Learning Disorders,” Journal Times, February 7, 2012, http://goo.gl/L8n7x1; Allington (2012). For the British version, see “Dyslexia Is NOT a Disease. It Is an Excuse for Bad Teachers,” Mail Online, March 2, 2014, http://goo.gl/BeyLtt.
Whereas a 2009 cover article: Gabrieli (2009); Elliott & Gibbs (2008); see also Elliott & Grigorenko (2014).
Keith Stanovich: Stanovich (1994).
Extreme skepticism about dyslexia: For somewhat different views, see Dorothy Bishop, “My Thoughts on the Dyslexia Debate,” BishopBlog, March 20, 2014, http://goo.gl/bAs79p, and Elliott & Grigorenko (2014).
dyslexia and ADHD were invented: A colleague from education has suggested that Allington’s rhetoric was in the service of a constructive goal, dissuading teachers from abandoning responsibility for their poorest-performing children because they have a disability. The ends are not justified by dissembling about the existence of the condition, however.
Given this behavioral overlap: As Willcutt et al. (2010a) stated in a review of the etiology of reading disability (dyslexia), math disability, and ADHD, “There is currently no valid genetic test for [these conditions], and it is unlikely that a definitive diagnostic test will be developed in the near future. Because most developmental disorders have polygenic, multifactorial etiologies in which each risk factor confers only a small increase in susceptibility, it is unlikely that any specific risk factor will have sufficient predictive power to be useful as a diagnostic measure.”
an elegant solution: Fletcher & Vaughn (2009).
For dyslexia they are questions: See Peterson & Pennington (2012).
Repeatedly it has been found: Goswami (2015).
a low-vision problem: Frith & Happé (1998).
impairments do not just co-occur: See Peterson & Pennington (2012) for discussion.
Co-occurring conditions can also result: Bishop (2009).
researchers have powerful quantitative methods: Willcutt et al. (2010a), for example.
The pioneering experiment was conducted: Scarborough (1990).
One study followed at-risk children: Muter & Snowling (2009).
Maggie Bruck’s invaluable studies: Bruck (1990, 1992).
A later study from this group: Hulme et al. (2015).
Picture babies: Linda Geddes, “The Big Baby Experiment,” November 4, 2015.
Speech sounds elicit: Richardson et al. (2003).
exposed to maternal smoking: Key et al. (2007).
anomalous evoked potentials in responses: Espy et al. (2004).
hidden unit activations: The figures show the contributions of each hidden unit to the activation of a phonetic feature critical for the “ee” vowel as in “eat.”
phonological impairment: The phonological impairment was implemented in several ways that had similar effects on the model’s behavior. One of the methods instantiated the idea that dyslexics benefit less from each learning experience. The weights in the network would change in the normal manner on each training trial, but the changes were not wholly retained. Neurobiological mechanisms that may have this type of effect have recently begun to be identified. Pugh et al. (2014).
Consider this behavioral study: Perrachione et al. (2011).
Similar effects have been observed: See, for example, Pugh et al. (2008).
In the real world: In a series of studies, Anne Sperling, Frank Manis, Zhong-lin Lu, and I found evidence for noisy visual processing in dyslexia. For example, in one study (Sperling et al. 2006) we created visual stimuli for a motion-detection task that were presented with high or low levels of visual noise. (An example can be found on seidenbergreading.net.) Dyslexics performed as well as nondyslexics with low noise levels but much worse at higher noise levels, meaning they were less able to ignore or inhibit the irrelevant visual noise. Our other studies suggested that noisy processing may be internal to the visual system (Sperling et al. 2005). The research did not address how often such deficits occur in dyslexics and nondyslexics, how the impairments develop, and whether they co-occur with other impairments, however.
brain solves the problem: If letter names are critical to the formation of letter categories, multiple representations for syllables such as “bee” and “eff” would also lead to a less efficient solution, though this observation is entirely conjectural.
documented in multiple languages: Ziegler & Gowami (2005).
Some years ago a team: Paulesu et al. (2001).
dyslexia spectrum: Snowling & Hayiou-Thomas (2006).
A small number of neuroimaging studies: Diehl et al. (2014).
Knowing that a celebrity: Gladwell (2013).
He describes a study: Diemand-Yauman et al. (2011).
For evidence, he relies: Logan (2009).
My guess: For a far more revealing and informative case study, I recommend the renowned artist Chuck Close, starting with this long interview: “Oral History Interview with Chuck Close, 1987 May 14–September 30,” Archives of American Art, http://goo.gl/1mXoit. Chuck Close identifies as dyslexic and prosopagnosic and is forceful in asserting that his disabilities shaped his life and art. The Close interview provides a wealth of detail. For example, his description of his dyslexia matches that of many other dyslexics. He describes discovering coping strategies such as getting more time for assignments, avoiding timed tests, and having someone check his spelling. He became an outstanding student. Tellingly, he mentions that his daughter is also dyslexic. His prosopagnosia seems closely related to his art; however, his story is complex, like every other. He describes intense interest in drawing from a young age, before a reading impairment would have manifested. Art came easily to him; reading did not. Art was rewarded; reading was a source of embarrassment and humiliation. Close is deeply insightful about his conditions and their impact on his work and life history, and probably a clearer example of how an impairment can enable a person to achieve extraordinary success.