ASD and Literacy : Characteristic Styles or (Specific) Deficits


These summaries explore, firstly, the nature of decoding and of comprehension abilities among children with ASD; and, secondly, the matter of visual impairments or over-sensitivity, and the reported benefits of coloured overlays for use when reading passages of text.

(In the context of sensory performance, a  brief mention is also made of auditory stress or processing difficulties for which benefits from auditory integration therapy have been claimed, but empirical research continues to find little valid evidence in support of the claims.)


M.J.Connor                                                                                                March 2007


[ This set of notes might usefully be read along with the earlier papers  “ Pupils with ASD : Teaching Approaches and Literacy ” August 2004; “ Scotopic sensitivity and Reading ” September 1991; and  “ Auditory Integration Training ” April 1995)


Patterns of Reading in ASD


The paper by Nation et al (2006) begins by citing what the authors to be a common assumption that reading is a relative strength among children with autistic spectrum disorders, but they note that there is actually a lack of systematic evidence concerning reading abilities among the ASD population.


Their review of existing literature demonstrates two contrasting themes.


Firstly, it is generally accepted that poor oral language skills carry an enhanced risk for poor or minimal written language skills (see, for example, Bishop and Snowling 2004).  Given that language impairments or weaknesses are a common concomitant of ASD, it is logical to assume that many children diagnosed with ASD will experience problems in learning to read.

Secondly, and conversely, there are various studies which have demonstrated very high levels of reading skill (accuracy) among children with autism and ASD.

However, caution is advised when it comes to interpreting the significance of single case studies or in seeking to generalise the findings across children who cover a wide spectrum of cognitive and linguistic capacities. 


This advice is all the more appropriate when it is recognised that reading is a complex skill involving a range of interlocking components from the ability to decode an (unfamiliar) word to extracting the salient content of a passage of text and understanding its meaning.

Successful reading involves the skilful deployment of word identification strategies and of language processing mechanisms which combine to ensure a comprehension of the material.  However, these two processes can show variable development and an imbalance so that determining reading competence requires an assessment of both areas of functioning. 


A further review of studies concerning accuracy, conducted by these present authors, indicates that reading accuracy is commonly satisfactory or better among samples of children or adults with ASD … sometimes in advance of what would be predicted from  age and IQ. 

One specific question has concerned the “style” of young readers with ASD … ie  it might have been expected (see Frith and Snowling 1983) that the apparently common preference for, or strengths in, the visual modality would be reflected in strategies emphasising whole word memory or the use of decoding cues linked to word shape or pattern.  However, assessment of performance in reading non-words

(which would depend upon phonological-decoding strategies) did not differentiate children with ASD from control children. 


The complexity of this whole area is increased as a result of noting the question, following this above outcome, whether or not one could generalise findings from an ASD sample which included only children with satisfactory reading competence to the whole population of children with ASD who would cover a range of levels of reading competence … and Nation (1999) had already demonstrated the wide variation in word and non-word reading capacities among children with ASD.


Nevertheless, it can be accepted that a significant number of children with ASD are poor at dealing with non-words, despite their skill at reading actual words.  In other words, for such children reading accuracy is not based upon phonological decoding skills as is commonly the case in typical reading development. 


Meanwhile, there is a general acceptance that the comprehension capacities of children with ASD can often be poor.

For example, even among a high-functioning sample of children, Minshew et al (1994) found a significantly lower mean level of reading comprehension compared to the mean of a control group matched for cognitive ability.


This pattern (adequate or better reading accuracy level, but relatively poor comprehension of material read) may be described as a form of hyperlexia … and there does appear to be a frequent association between ASD and hyperlexia (and, many children identified as hyperlexic may also be shown to have ASD or, at least, some of the characteristic features of autism). 

In her earlier paper (Nation 1999, op. cit) it was speculated that this finding could reflect a number of possible factors including a focus upon local rather than global features or specific patterns of linguistic strengths and weaknesses. 


Nation et al then return to their theme of problems over generalising, and ponder whether excluding from analyses those children with poor language and literacy could have resulted in an overestimation of typical reading accuracy among children with ASD.

Their own study set out to assess a range of reading skills among children with ASD.  In particular, the questions concerned the overall level of reading ability in a broad and widely representative sample of the ASD population; the levels of component skills (accuracy and comprehension); whether a discrepancy between relatively good accuracy and relatively poor comprehension is characteristic of the reading profile of children with ASD; and whether difficulty in decoding unfamiliar words  or non-words is also a characteristic of children with ASD. 


The target sample comprised 41 children with a mean age of 10 years (36 boys and 5 girls) of whom 16 met the criteria for autism, 13 for atypical autism, and 12 for Asperger Syndrome.  One criterion for inclusion was that minimal language skills be present.

The children were assessed on their reading accuracy (The Graded Nonword Reading Test, British Ability Scale reading subtest, and Neale Analysis of Reading Ability); reading comprehension (Neale Analysis); oral language skill (BPVS, and WISC comprehension subtest); and non-verbal ability (WISC block design subtest). 


The findings included normal range levels of reading accuracy across the group, but reading comprehension was generally lower.  However, there was such wide variation in all the reading tests within the group that overall mean scores had to be regarded as not very informative.

A large proportion of the group showed impaired comprehension for the material read, with 65% of the participants gaining a reading comprehension score at least 1 SD below the population norm, and around 33% of the participants showing a greater severity of comprehension difficulties.

In some cases, poor comprehension could be linked to poor accuracy; but, of the 20 children who showed normal word reading skills, 10 showed limited comprehension

(which obviously could not be explained in terms of poor accuracy and impaired access to the text in the first place).   Thus, comprehension deficits may be a concomitant of general impairments in processing and understanding language.


The implication, continue these authors, is for ongoing research to explore precisely where in the comprehension process the difficulties are located. 

Reference is made to O’Connor and Klein (2004) who listed various aspects of comprehension that might be challenging to individuals with ASD ….


(However, it was considered encouraging by Nation et al that this same study found that people with ASD could focus upon, and show improvements in their comprehension, when given specific cues about what to look for or having their attention directed to links between elements in the text … such as the various clauses or sub-clauses all providing information about the same person or object albeit simply via the use of pronouns). 


In the current set of findings produced by Nation et al, it was noted that despite at least measurable or even adequate word reading skill observed across their sample, there were still a large number of participants who had difficulty with non-words. They suggested that this might seem surprising if non-words need to be decoded part by part which may suit an autistic style, especially when the study by Minshew et al (op cit) found high functioning children with ASD were rather better at reading non-words than actual words. 


The authors sought to explain this apparent discrepancy in terms of the sampling differences.  Their own sample of participants was not selected on the basis of reading ability or IQ.  Therefore, it could be that some children do have significant difficulty in applying phonological decoding strategies (and there is a clear link between phonological weaknesses and poor performance in  non-word reading). 

This difficulty may be associated with impairments in the use/processing of oral language.

Alternatively, the relative superiority of word reading over non-word reading could be explained by the trend among their sample of children with ASD to adopt a rote memorisation strategy or to use visual cues to cope with word reading.  Such a trend would help word reading, but would not be of much use in dealing with non-words.


In any event, the finding of high levels of poor comprehension is consistent with the view that hyperlexia is commonly associated with ASD.
However, the authors note that a precise definition of hyperlexia is not that easy to achieve.  The central feature is a superiority of word reading skills over reading comprehension, but it may also involve an unusual pre-occupation with reading, a very early and possibly spontaneous onset of word recognition, and a mismatch between proficient reading accuracy and limited social and cognitive skills. 

It is recommended by Grigorenko et al (2003) that the label of hyperlexia be limited to those individuals with a pervasive developmental disorder who show all these features.  (The suggestion is that the validity of this view is tested by comparing children who show hyperlexic reading but who differ in respect of the other features.)


Nation et al conclude by noting how their study confirms reading to be anything but a simple or unitary construct but that certain component skills may be lacking, or the integration of sub-skills inefficient, among children with a developmental disorder. 

The practical implication is that using a basic test of word recognition may lead to some over-estimation of general reading competence (notably comprehension but also, for some children, decoding skill). 

Good or above average reading accuracy does not guarantee satisfactory reading comprehension, and assessing children’s competence requires a recognition of the various components and the heterogeneity of reading skills even within a sample of children sharing the diagnosis of ASD.


Reported Benefits of Coloured Overlays for the Reading of Children with ASD


The paper by Ludlow et al (2006) acknowledges that the core deficits in autism and ASD are concerned with social interaction, language, and imagination, but their concern is with dysfunctions that may be observed in respect of perceptual processing.  This kind of disadvantage is all the more of a problem in the light of the very few studies which have investigated the precise nature of the autistic hypersensitivity to certain stimuli.

Anomalies are difficult to quantify, and findings may be difficult to interpret (or to generalise) because of methodological issues such as absent controls for age and measured ability.


These authors are concerned with visual stress or discomfort (scotopic sensitivity), and they cite the work of Irlen (1991) who described how reading performance can be influenced by colour processing.

This issue has also been noted, and followed up in various publications, by Arnold Wilkins and various associates who have referred to the occurrence of pattern glare from a page of text that can cause eye strain or perceptual distortions such as a blurring or apparent movement of letters on the page. 


Experimentation has shown that the discomfort or distortions are reduced when the print is lit with a particular colour.  Wilkins et al (1996) found reduced symptoms of eye strain or headaches when individuals read text through glasses tinted with some selected and optimal colour. 

Later studies have reported that the use of coloured overlays can have the same benefits in terms of reducing the negative effects and of enhancing reading performance, and claims have been made for improvements in both the rate of reading and reading accuracy.


Wilkins et al (2001) have found that, when individuals are given the chance to select their optimal overlay, their choice tends to be consistent over sessions; and the greatest consistency in selecting overlays is associated, among children, with the most improvement in reading. 

It is further argued that the benefits are not the result of a placebo affect (following trials involving a range of overlays or no overlay). 


In seeking to understand the observed effects, Wilkins (2003) has proposed that distortions are the result of a spread of activation within the cortex which causes cells to fire inappropriately … a form of cortical hyper-excitability. 

The use of coloured filters changes the distribution of firing within the cortex and the excitation is reduced …. a hypothesis that is said to have gained support from MRI studies which set out to explore the hyper-excitability associated with migraine.

This hypothesis predicts that coloured filters will be beneficial in a range of CNS conditions where hyper-excitability of the visual cortex is a feature (such as photosensitive epilepsy).


The current authors (Ludlow et al : op. cit) note that individuals with autism seem more liable than chance to epilepsy, and they explored the possibility that cortical excitation is a significant feature in many such children, and that the use of coloured filters could have the effect of reducing perceptual distortions and producing observable benefits (in reading performance, for example).

Their specific goal was to determine whether a sample of children with autism will read more quickly and more accurately when allowed the use of overlays compared to matched controls without access to overlays. 


The target sample comprised 19 children between the ages of 8+ and 15 years all of whom attended specialist schools for which a formal diagnosis of autism was a prerequisite for admission. 

The controls included two groups … typically developing children from mainstream schools, and children with moderate learning difficulties drawn from specialist schools.  They were matched with target children for age, gender, and “verbal IQ”. 


(The present writer - MJC - was a little worried to note that matching for verbal IQ was carried out by means of the British Picture Vocabulary Scales whose results may show a degree of positive correlation with scores derived from a valid test of verbal IQ but which themselves are actually a measure of vocabulary recognition, hardly verbal IQ).


The children were invited to read a test passage of text, and were questioned about whether the letters appeared to move or stay still, or whether they were clear or fuzzy, and whether it hurt their eyes, etc.

A second and similar page was introduced, and the children were asked to read it for 1 minute either with or without the overlay of their choice.  These overlays could be single or double according to the preference expressed by the children. The order in which the reading was completed with or without the overlay was randomised.  

Rate of reading was measured in each case.


When a 5% increase in reading speed was selected as the criterion for significant improvement, it was reported that more children from the autism group increased their reading speed than children from the matched control group. 

Individual data revealed that a number of the children with autism showed a much greater increase in reading speed.  

It was further argued that existing reading level and “verbal IQ” did not act as significant intervening variables. 


All the children with autism reported that the overlays made the text clearer while none reported a preference for a white overlay or for no overlay. 

The great majority of the control group also showed a preference for the use of overlays, and all the children described a decrease in visual discomfort when using the overlays.  However, these reports about changes in visual stress were not found to be of statistical significance, and it was speculated that this could be an artefact of the method involving self report which depended upon accurate understanding of the questions. 

Meanwhile, despite wide variation in the range of choices of colour for the overlays, all the children showed individual consistency in their colour choice; and it was concluded that, in the light of the reading rate improvements, their choice was effective.


The authors held that a logical next step would be to compare the reading performances of children with autism when using overlays of their preferred colour and strength and when using overlays chosen for them in order to check for the effects of novelty and to determine whether there is any link between the colours chosen and particular subgroups of readers. 

It was also felt logical to continue studies by which to determine whether the children with autism who benefit most from the coloured overlays are over-represented in groups that are also prone to epilepsy or migraine. 


The authors acknowledged that these results should be taken as preliminary with a need still to identify those children who would benefit most from overlays … with the possibility, for example, that verbal IQ or existing reading capacity would prove to be differentiating factors when the reading task is more challenging in respect of difficulty or duration.


Nevertheless, they conclude that their results are important in emerging from the first empirical study of improvements in reading skill (rate) through the use of coloured overlays among children with autism.  


(The present writer - MJC - would simply speculate over the validity of the initial assumption of this study that children with autism would be particularly prone to visual stress and discomfort.  One might also form the view that scotopic sensitivity and the use of overlays is hardly a central theme in current literacy research. 

However, the use of overlays has been one possible “tool” available to teachers who are working with children who have some observable weaknesses in the acquisition of literacy, and this will presumably remain the case. 

One should not assume, as with any single interventionist strategy, that wide-spread benefits will consistently emerge from their use.  Some children from the population at large or from particular sub-populations may well benefit; and there would be value in further work on seeking to define those children [ and their particular profiles of strengths and weaknesses ] for whom benefits from the use of overlays would be most confidently predicted.)


Auditory Integration and Autism


While the present writer - MJC - recognises that auditory integration training (AIT) is a little removed from the general theme of these notes concerning literacy and autism, there is something of a link in respect of processing styles or deficits.


In any event, the work of Sinha et al (2006) describes how the proponents of AIT have held that it can reduce the behavioural or cognitive symptoms associated with a number of conditions, including autistic spectrum disorders.


Sinha et al surveyed the field for research findings based upon controlled and randomised trials of AIT, using standardised scores as outcome measures, among children or adults with pervasive disorders. Six such studies were identified but outcome measures were not consistent making it impossible to conduct an overall analysis (meta-analysis). 

Additional difficulties were observed with these studies, such as the lack of information about allocation of participants to groups; the lack of use of “blind” raters when it came to the evaluation of outcomes; and wide variation in the time before follows-up.


The conclusion was that sound therapy for autistic spectrum disorders is “an experimental treatment at best”. 


A commentary by White and Giorgadze (2007) highlights the limited evidence base for AIT, and the methodological flaws among those trials which have been published.

Nevertheless, they continue, there is much anecdotal evidence for benefits, and these authors are concerned lest false hope or expectations are maintained about this approach, and they trust that parents and others can gain access to the wider picture.


                                   *          *          *          *          *          *


M.J.Connor                                                                                                March 2007 





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This article is reproduced by kind permission of the author.

© Mike Connor 2007.

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