Article for Category: ‘Dyslexia’

Does medication improve reading ability?

September 05th, 2016

The Journal of Child and Adolescent Psychopharmocology has published an article by Shaywitz et al that investigated the affects of the drug atomoxetine (sold as Strattera) on reading and attention in children with dyslexia, ADHD and comorbid dyslexia + ADHD.

My understanding is that the experiment was part of a broader study on the effectiveness of atomoxetine as a treatment for ADHD. The study appears to have been funded by Eli Lilly and the second author is reportedly an employee and minor shareholder in Eli Lilly.

Children were defined as having dyslexia if (a) there was at least a 22-point discrepancy (approx. 43 percentile ranks) between IQ and word-reading ability (defined by the WJIII Word Attack test OR the Word Identification OR the WJIII Basic Reading Cluster – an average of Word Attack and Word Id) or (b) the child had a standard score of 89 or lower on at least one of the WJIII tests.

The first thing that springs to mind is that these criteria are not particularly stringent. A standard score of 89 represents the 23rd percentile. It is still within a standard deviation of the mean. Further, the discrepancy criterion presumably means that a child with an IQ score of 122 and a reading score of 100 (exactly average) met criteria for the dyslexia group.

Using these criteria, 209 children who were allocated at random to an atomoxetine or placebo group. Numbers in each group were: dyslexia only (n = 29 atomoxetine, n = 29 placebo), ADHD + dyslexia (n = 64 atomoxetine, n = 60 placebo) and ADHD only (all of whom received atomoxetine).

The drug trial lasted for 16-weeks. Changes in reading skills were measured by:

WJIII Word Attack and Word Identification tests

WJIII Spelling

WJIII Reading Comprehension and Reading Vocabulary

Comprehensive Test of Phonological Processing (CTOPP)

Gray Oral Reading Tests-4 (GORT-4)

Test of Word Reading Efficiency (TOWRE)

It is unclear why but on many variables the Placebo group had higher pre-treatment reading/spelling skills than the Atomoxetine group. For example, within the Dyslexia only group the Placebo sub-group had an average standard score on the Word Attack subtest of 88.05 while the Atomoxetine group had an average score of 84.11. It was 83.86 vs 80.47 for Word Identification, 83.32 vs 77.32 for Spelling. This may seem a minor point but consider the effect of regression to the mean http://www.understandingminds.com.au/blog/2012/02/. The more extreme a score is at pre-test the more likely it is to “bounce’ back towards average at post-testing. Thus, the Atomoxetine group was more likely to “benefit” from regression effects than the Placebo group.

A summary of the interesting bits of the results:

  • Children with dyslexia who were treated with atomoxetine made greater gains than children with dyslexia given the placebo treatment on WJIII Word Attack, WJIII Basic Reading Cluster and WJIII Reading Vocabulary.
  • Children with dyslexia + ADHD who were treated with atomoxetine made greater gains than children with dyslexia + ADHD given the placebo treatment on the CTOPP Elision test (a peripheral/distal reading sub-skill).

So what?

  1. At first glance it seems odd that children with dyslexia would respond better to a medication designed for ADHD than children who actually had ADHD. However, there are reasonable explanations. First, medication isn’t a panacea. It doesn’t cure ADHD. It improves symptoms. It is possible that the ADHD + dyslexia remained more impaired than the dyslexia group even when given medication. Second, children with dyslexia often have sub-threshold symptoms of ADHD that may in fact respond better to medication than the more severe symptoms seen in children actually diagnosed with ADHD.
  2. It is possible that at least some of the effects were due to greater regression to the mean in the Atomoxetine vs Placebo group (see above).
  3. It is possible that the medication simply improved test behaviour rather than reading ability per se.

The data are arguably the beginning of a research journey. They provide some preliminary support for the idea that psycho-stimulant medication can improve academic skills even in children without ADHD. However, I am sceptical about this. I can see how medication might improve test-taking behaviour in some children. I can also see how it might “smooth out” the inconsistency seen in children with attention problems and with dyslexia. However, medication doesn’t teach. It doesn’t matter how good your attention is; if you don’t know it you don’t know it.

I am more interested in how medication affects response to reading intervention. The graph below shows data from a single case seen in my clinic. The case is of a male with ADHD + mixed dyslexia. He was receiving reading intervention delivered 4/week. See here http://sgo.sagepub.com/content/spsgo/1/2/2158244011420452.full.pdf and here http://sgo.sagepub.com/content/early/2011/11/01/2158244011428159 for descriptions of the program.

 

The data points represent a weekly nonword reading test. The test items were constructed using the grapheme-phoneme conversion rules taught in the intervention program. If the student learns ~4-5 new GPCs weekly they should be able to read ~5 extra nonwords each week. The “flat lines” represent data from 2 x baseline periods and 2 x treatment periods in which the participant was receiving reading intervention only. One can see that not much progress was being made. It wasn’t that the boy wasn’t learning new things. It was more than his “recall” was inconsistent and his test-taking behaviour was poor.

Upwards growth in test scores were seen almost immediately upon beginning to take a stimulant medication. Later data, not shown in the graph, showed that removing the reading intervention so the only treatment was medication resulted in a return to a flat line. That is, the medication didn’t teach skills.

We have seen this pattern in several cases now; although the results of other cases have not been as dramatic as this first case.  (I should also point out that the skeptic in me thinks that these data are too perfect and I need to see them replicated before I truly “believe” them).

Our very preliminary conclusions are that attention is necessary for new learning to take place and that the medication helps set the conditions for learning to happen (the batter into which the teaching is stirred if you will). However, medication will probably not make you a good reader sans the teaching.

At this point there is no justification for trialling medication in students who just have dyslexia. However, we hope to see a larger trial of the response of students with ADHD + dyslexia to reading intervention versus medication + reading intervention.

For help with dyslexia, ADHD, autism spectrum disorders and other developmental and learning disorders in the Gold Coast and Tweed regions contact the Understanding Minds Clinic.

 

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Abstract of the day #3: Is the visual analyzer orthographic-specific? Reading words and numbers in letter position dyslexia

May 15th, 2013

Friedmann et al. (2010).Is the visual analyzer orthographic-specific? Reading words and numbers in letter position dyslexia

Cortex. 2010 Sep;46(8):982-1004.

Letter position dyslexia is a deficit in the encoding of letter position within words. It is characterized by errors of letter migration within words, such as reading trail as trial and form as from. In order to examine whether Letter position dyslexia is domain-specific, and to assess the domain specificity of the visual analysis system, this study explored whether Letter position dyslexia extends to number reading, by testing whether individuals who have letter migrations in word reading also show migrations while reading numbers. The reading of words and numbers of 12 Hebrews-peaking individuals with developmental Letter position dyslexia was assessed. Experiment 1 tested reading aloud of words and numbers, and Experiment 2 tested same-different decisions in words and numbers. The findings indicated that whereas the participants with developmental Letter position dyslexia showed a large number of migration errors in reading words, 10 of them read numbers well, without migration errors, and not differently from the control participants. A closer inspection of the pattern of errors in words and numbers of two individuals who had migrations in both numbers and words showed qualitative differences in the characteristics of migration errors in the two types of stimuli. In word reading, migration errors appeared predominantly in middle letters, whereas the errors in numbers occurred mainly in final (rightmost) digits. Migrations in numbers occurred almost exclusively in adjacent digits, but in words migrations occurred both in adjacent and in nonadjacent letters. The results thus indicate that words can be selectively impaired, without a parallel impairment in numbers, and that even when numbers are also impaired they show different error pattern. Thus, the visual analyzer is actually an orthographic-visual analyzer, a module that is domain-specific for the analysis of words.

 

For help with dyslexia on the Gold Coast and Tweed regions contact the Understanding Minds Dyslexia & Reading Difficulties Clinic .

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Abstract of the day #2: The frequency and significance of the word length effect in neglect dyslexia

May 15th, 2013

Reinhart et al. (2013). The frequency and significance of the word length effect in neglect dyslexia. Neuropsychologia.

Neglect patients often omit or misread initial letters of single words, a phenomenon termed neglect dyslexia. Omissions of whole words on the contralesional side of the page during paragraph reading are generally considered as egocentric or space-based errors, whereas misreading of the left part of a word can be viewed as a type of stimulus-centred or word-based, neglect-related error. The research of the last decades shed light on several effects of word features (such as written word frequency, grammatical class or concreteness) that modulate the severity of neglect dyslexia. Nevertheless, almost all studies about those modulating factors were case studies and some of them have not been replicated yet. Therefore, to date we do not know how relevant such effects of different word stimuli are for a population of neglect dyslexia patients. Knowing their incidence would improve our theoretical understanding of neglect dyslexia and promote the development of standardized neglect dyslexia assessments, which are lacking so far. In particular, case studies have shown that neglect dyslexia error frequency increases systematically with word length (word length effect, WLE) while other single case studies found contrary results. Hence, the existence of the WLE in neglect dyslexia is unsettled and its incidence and significance in stroke patients is unknown. To clarify this issue we evaluated the relation between word length and the extent (number) of neglected or substituted letters within single words in neglect dyslexia (neglect dyslexia extent, NDE) in a group of 19 consecutive neglect dyslexia patients with right hemisphere lesions. We found a clear WLE in 79% (15 of 19) of our neglect dyslexia patients, as indicated by significant correlations between word length and NDE. Concurrent visual field defects had no effect on the WLE in our sample, thus showing no influence of early visual cortical processing stages on the WLE in neglect dyslexia. In conclusion, our results suggest a clear relationship between word length and reading errors in neglect dyslexia and show that the WLE is a frequent phenomenon in neglect dyslexia.

 

For help with dyslexia on the Gold Coast and Tweed regions contact the Understanding Minds Dyslexia & Reading Difficulties Clinic .

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Abstract of the day: Letter position dyslexia in Arabic: From form to position

May 15th, 2013

Naama Friedmann and Manar Haddad-Hanna (2012). Letter position dyslexia in Arabic: From form to position. Behavioural Neurology, 25, 93-103.

 

This study reports the reading of 4 Arabic-speaking individuals with letter position

dyslexia (LPD), and the effect of letter form on their reading errors. LPD is a peripheral dyslexia

caused by a selective deficit to letter position encoding in the orthographic-visual analyzer, which

results in migration of letters within words, primarily of middle letters. The Arabic orthography is

especially interesting for the study of LPD because Arabic letters have different forms in different

positions in the word. As a result, some letter position errors cause letter form change. We compared

the rate of letter migrations that change letter form with migrations that do not change letter form in

3 Arabic-speaking individuals with developmental LPD, and one bilingual Arabic and Hebrewspeaking

individual with acquired LPD. The results indicated that the participants made 85% letter

position errors in migratable words when the resulting word included the letters in the same form,

whereas migrations that caused letter form change almost never occurred. The error rate of the

Arabic-Hebrew bilingual reader was smaller in Arabic than in Hebrew, but when only words in

which migrations do not change letter form were counted, the rate was similar in Arabic and

Hebrew. Namely, whereas orthographies with multiple letter forms for each letter might seem more

difficult in some respects, these orthographies are in fact easier to read in some forms of dyslexia.

Thus, the diagnosis of LPD in Arabic should consider the effect of letter forms on migration errors,

and use stimuli that are migratable words that do not require letter-form change. The theoretical

implications for the reading model are that letter form is part of the information encoded in the

abstract letter identity, and thus affects further word recognition processes, and that there might be a

pre-lexical graphemic buffer in which the checking of orthographic well-formedness takes place.

 

For help with dyslexia on the Gold Coast and Tweed regions contact the Understanding Minds Dyslexia & Reading Difficulties Clinic .

Like us on Facebook for updates on dyslexia related matters, information on other developmental disorders like autism spectrum disorders, Asperger’s and ADHD, and general mental health info.

 

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Dyslexia is a problem with the word-reading system

May 15th, 2013

Dyslexia is a problem with the word-reading networks in the brain.

Dyslexia literally means poor (dys) with words (lexia). The individual with dyslexia has difficulty reading the words on the page; it is not a problem with comprehension. The weakness in word-reading is most notable when reading words in isolation. People with dyslexia often read better in context because they are able to use other skills and information to make up for weaknesses in word-reading. Ironically, this contextual facilitation effect means that many bright children with dyslexia remain unidentified because most reading tests conducted in schools use stories.

 

For help with dyslexia on the Gold Coast and Tweed regions contact the Understanding Minds Dyslexia & Reading Difficulties Clinic .

Like us on Facebook for updates on dyslexia related matters, information on other developmental disorders like autism spectrum disorders, Asperger’s and ADHD, and general mental health info.

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