Article Archive for ‘March, 2012’

Vision therapy and dyslexia: What’s the evidence?

March 25th, 2012

The title of the original version of this post may have implied that vision therapy is an inappropriate treatment in general. Whereas, I intended only to refer to it as inappropriate for treating dyslexia/reading problems. There is evidence that vision therapy is an appropriate treatment for some vision problems such as convergence insufficiency. I regret that any adverse inference may have been drawn from the title.

Vision and reading

Many people have attributed reading problems to one or more subtle ocular or visual abnormalities, including Samuel Orton, who wrote about the difficulty he thought children with dyslexia had with reversible letters and words (eg. b/d, god, dog). However, scientific research has shown that Orton’s view and other views that reading problems are the result of issues with visual processing, visual perception or visual memory are almost certainly incorrect.

In the 1970′s Frank Vellutino and colleagues performed a series of studies in which they compared poor and good readers on a variety of visual processing tasks (e.g., visual discrimination, spatial orientation, visual memory, and visual learning). Most importantly, the tasks carefully controlled for verbal coding ability.

For example, Vellutino et al. found that memory for visually presented words and letters that were visually similar (e.g., b/d, was/saw) was the same in good and poor readers when a written rather than a verbal response was required. In other words, the kids with dyslexia see the same thing and can replicate the symbol but have more difficulty producing the letter or word name verbally. Another experiment showed that good and poor readers performed equally on visual recognition and recall of symbols from the Hebrew script with which both groups were equally unfamiliar. Finally, poor readers do make more ‘visual’ errors when reading compared to good readers of the same age. However, they DO NOT make more ‘visual’ errors than younger children of the same reading age. These data tell us that ‘visual’ errors are the result of poor reading, not the cause.

Even when individuals make errors that seem “visual”, such as migration errors within words (e.g., reading trail as trial) or between adjoining words (e.g., reading fig tree as fig free) what seems to be a visual or attention problem is actually a specific problem with the word-reading process. We know this because people who make these errors do not make the same errors for digit stimuli.

Eye movements and dyslexia

The eye movements of individuals who have dyslexia do differ from those of skilled readers (Rayner, 1998). While reading, the people with dyslexia exhibit longer duration of eye fixation, shorter saccades and a higher proportion of regressions (backward) saccades than controls (Huxler et al., 2006). However, research has demonstrated that abnormalities in eye movements occur specifically in reading tasks. When people with dyslexia and controls are compared on non-reading visual tasks that require similar perceptual and ocular motor demands to reading, there are no differences between eye movements of the groups. Hence the divergent eye movement patterns of people with dyslexia during reading reflect difficulties in the reading process rather than a primary impairment of ocular motor control (Huxler et al., 2006). This conclusion is supported by studies that have demonstrated that the eye movements of people with dyslexia do not differ from younger, reading age matched controls (Hyona & Olson, 1995) and that when people with dyslexia are given reading-level texts, their eye movements are comparable to controls (Olson et al., 1983).

Vision therapy

Vision therapy involves eye exercises, eye-hand coordination tasks and other exercises designed to improve the individual’s motor memory activity. Although in widespread use, a number of reviews have concluded that vision therapy has limited evidence for efficacy (e.g., Barrett, 2009Bishop, 1989, Wright, 2007). In response to concerns regarding the use of visual therapies, a number of influential bodies have conducted reviews and released policy statements for their members. For example, the joint statement of the Committee on Children With Disabilities, American Academy of Pediatrics, American Association for Pediatric Ophthalmology and Strabismus, and the American Academy of Ophthalmology states the following in regard to visual therapy:

“No scientific evidence supports claims that the academic abilities of children with learning disabilities can be improved with treatments that are based on 1) visual training, including muscle exercises, ocular pursuit, tracking exercises, or ‘training’ glasses; 2) neurological organisational training (laterality training, crawling, balance board, perceptual training).”

They go on to say that: “diagnostic and treatment approaches for dyslexia that lack scientific evidence of efficacy such as behavioral vision therapy and eye muscle exercises are not endorsed or recommended.”

Other recent reviews (e.g., The American Academy of Ophthalmology; Wright, 2007) have concluded that there is no scientific evidence that supports behavioural vision therapy or orthoptic vision therapy as effective treatments for reading difficulties. Claims of improvement after visual therapy have typically been based on poorly controlled studies and testimonials and reported benefits can often be explained by the traditional educational strategies with which vision therapies are usually combined or by placebo effects. Eye movements and visual perception are not critical factors in the reading impairment found in dyslexia and the majority of people with known ocular motility and eye movement defects read normally and even people with severely misaligned eyes can excel in reading and academics.

What is the evidence?

Evidence for any form of therapy can come from two sources: (a) theoretical evidence linking a treatment to a problem in a logical manner (e.g., excessive caloric intake results in weight gain so reducing caloric intake will probably result in weight loss) and (b) direct evidence for the efficacy of the treatment in reducing symptom severity (e.g., reducing caloric intake leads to greater weight loss in people with obesity compared to a placebo treatment). Of the two, the latter is a far stronger form of evidence. Both of these forms of evidence are missing for vision therapy as a treatment for dyslexia/reading problems.

Theoretical evidence linking vision and vision therapy to reading

It is likely true that people with dyslexia and other reading difficulties experience vision problems. However, it is also likely that there are good readers who experience vision problems. To prove causality between low scores on vision/visual processing tests one would have to demonstrate: (a) the vision/visual processing problems are specific to individuals who have reading problems, (b) that individuals who have vision/visual processing problems have different behavioural sequelae to individuals who do not have vision/visual processing problems, (c) that therapy that targets the putative visual problem leads to improvements in reading skills in the therapy group but not in an equivalent control group who received a placebo therapy and, (d) vision therapy produces greater gains in reading ability than reading intervention alone. There is currently no evidence showing a-d to be true. Therefore, one has to conclude that there is limited theoretical evidence for using vision therapy to treat reading problems.

Evidence for efficacy

The importance of demonstrating that vision therapy is an effective and therefore appropriate treatment for reading problems has been highlighted in a recent review (p. 5). It was noted that: “Demonstrating treatment efficacy is especially important here because these children and their parents represent a vulnerable group” and  “the onus is clearly on treatment providers to produce the evidence in support of the treatment(s) that they are offering. Without such evidence, parents inevitably run the risk of wasting their time, effort and resources, and they and their children may become disillusioned if expectations are repeatedly raised and then dashed.

There is currently no evidence that vision therapy improves reading ability directly or that greater reading growth occurs following vision therapy (i.e., that it enables better learning). The one study of sufficient scientific merit showed that vision therapy did not improve reading and spelling scores in poor readers compared to a control group of poor readers who received a placebo treatment.

Given the widespread use of vision therapy in a range of learning difficulties and its considerable cost, in terms of money and time, it is astounding that the clinicians and professional bodies that represent those clinicians have not invested in better research. The onus must surely be on clinicians and their professional bodies to prove scientifically that their treatments work. Until they manage that the conclusions of previous reviews that vision therapy is not recommended remain valid.




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Review of Success and Dyslexia

March 02nd, 2012

Perceptions of competence, contingency and control are all constructs related to coping and to emotional distress. Competence refers to the degree to which the individual believes himself or herself to be good (competent) at a task or skill. Contingency is the degree to which the individual believes that outcomes are contingent on their own behaviour. Control describes a general construct that measures how much control the individual feels in a given situation or for a given task. In the book Success and Dyslexia, authors Nola Firth and Erica Frydenberg take as their starting point that the coping strategies used by students who have dyslexia (and presumably other learning difficulties) tend to be passive and negative. These strategies typically betray a lower sense of competence, contingency and control than their higher-achieving peers. They recognise that passive and negative coping strategies not only adversely affect school performance but that they have the potential to lead to emotional distress. To help alleviate this problem they have developed an 11-step coping program.

The program is designed for middle primary students and runs on two fronts: as a whole class program with additional small-group work for students who have dyslexia. Four sessions (1-3 and 5) are devoted to developing awareness of helpful and unhelpful coping strategies and to help the students understand their own coping mechanisms. Session 4 is a goal setting session in which students are encouraged to develop a realistic goal they want to achieve over the course of the program. Although the authors do not explicitly say so, presumably helping the student attain a goal with effort and active coping will help develop a sense of competence, improve perceived contingency and make it more likely they will be motivated by opportunities to develop competence in the future.

Sessions 6-11 teach cognitive-behavioural principles to help students become aware of the link between cognitions (thoughts and images), emotion and behaviour. There is a large psycho-education component and skills training that some teachers and clinicians will be familiar with from social skills programs. For example, students are taught about positive self-talk and how to use assertive language and body language. While at times the authors seem to confuse the cognition and behavioural components of the cognitive model, they have done well to simplify the core component of the program down to a choice between helpful and unhelpful choices.

The book includes sufficient information and materials to allow a clinician or educator to run the program with reasonable fidelity. Other positives include the focus on the affective and strategic aspects of learning difficulties that are too often ignored and the way in which class teachers and non-LD students are involved directly in the therapy. Teachers are also provided with a list of useful accommodations for students who have dyslexia (pp. 7-8). Implementing these strategies alone would likely lead to better academic, emotional and behavioural outcomes. However, in my experience, professional development, including ongoing support from a skilled learning support coordinator would be necessary to ensure successful application of the accommodations within the classroom.

On the downside, it was unfortunate that the authors felt the need to highlight the dubious practice of including an IQ test in the “diagnosis” of dyslexia (p. 6). It might also have been good to draw attention to the possibility that the Success and Dyslexia program is not a substitute for intensive skills intervention. Given the current state of practice in this Australia, one cannot presume that a student who gets to middle primary grades as a poor reader has had the systematic intervention that we know can significantly reduce the effects of dyslexia.  It is hard to imagine that a student will develop a strong sense of well-being when their perceptions of low competence and control are entirely rational. Indeed, most adults would leave a job that made them face the daily failure that students with dyslexia typically experience. Perhaps the Success and Dyslexia program would work best in combination with an intervention designed to directly improve academic skills.



Managing challenging behaviour in children who have Asperger’s

March 02nd, 2012

Students who have Asperger’s Syndrome can display challenging behaviour. They may be ‘runners’ or they may lash out at teachers among other things. They usually do so because they are experiencing some form of emotional distress as a result of excessive/unpleasant sensory stimulation, because they have difficulty understanding other people’s perspectives, because they have difficulty coping with change, or because they have an otherwise inflexible behavioural repetoire, amongst other things.

A patient (male, 10 years of age) who we will call Jack (isn’t every second boy called Jack?) has been ‘running’ or punching/hitting/biting others, including teachers, when he is distressed. Jack’s support teacher has indicated to his mother that his behaviour is unpredictable and that therefore they are having difficulty managing him. In other words, they are finding it hard to identify the antecedents of his behaviour. Identifying antecedents is a good thing to do and changing them is very effective. For example, a child who becomes anxious about not knowing what to do when he first arrives in the classroom each morning (i.e., he doesn’t have a routine) can be assisted by getting him to class early and giving him a job (e.g., he can be book monitor or fish feeder etc). However, antecedents can be hard to find and it is not always possible to change them even if one is aware of them. Changing the behaviour of children who have Asperger’s therefore often requires a different type of behaviour therapy. Before we look at what that might be let’s quickly revisit B.F. Skinner’s laws of the universe.

  1. Positive reinforcement. When a behaviour is followed by a rewarding stimulus the likelihood of the behaviour occurring again is increased.
  2. Negative reinforcement. When a behaviour is successful in eliminating or reducing a distressing stimulus it is rewarded and the likelihood of the behaviour occurring again is increased.
  3. Punishment. When a behaviour is followed by a punishment the likelihood of the behaviour occurring again is decreased.
  4. Shaping. Human behaviour rarely changes immediately, just as young canines do not learn to walk without a leash on their first day of obedience training. Shaping is a conditioning procedure in which successive approximations of a behaviour are reinforced. Successive approximations refer to increasingly accurate representations of the behaviour desired by the teacher.  The principles of shaping can be illustrated in the training of a puppy. If one desires the puppy to sit and stay while you are out of sight, one doesn’t sit the puppy down and walk around the corner. Rather one teaches it to stay while you are beside it and have it on a tight leash. A reward is provided after it stays for the briefest of moments. The period for which it must stay and the distance between the puppy and owner is increased with rewards provided for successful performance at each increment until, finally, it is able to perform the desired behaviour.
  5. Positive reinforcement is more effective at changing behaviour than punishment.
  6. Behaviour management methods are neither right nor wrong; they’re just effective and ineffective.

Getting back to Jack; like many kids who have Asperger’s, he lacks the ‘software’ that allows him to make sense of his social world. He needs the adults around him to provide him with software ‘plug-ins’. How can we accomplish this? By using Skinner’s laws of positive reinforcement and shaping.

Jack is clearly trying to avoid distressing situations. That he continues to do so shows that the punishment being used by the school is not working and that his current behaviour, while maladaptive, is having a negatively reinforcing effect. A more effective method must be found.

The new approach can begin by writing a Social Story that describes for Jack how he might respond in a particular situation. This might include suggesting to Jack that when he begins to feel distressed in the classroom he is to (a) go to his teacher and ask for his iPod, (b) move to his quiet time area, (c) stay in his quiet time area until he feels like he can manage himself back in the class, (d) return to the class and discuss a solution to the problem with his teacher. Parents and the school then need to identify an external reward that may serve as positive reinforcement. Next, the teacher has to shape Jack’s behaviour by paying attention to him and trying to catch him doing something that resembles the terminal goal of following the ‘calm down’ procedure described above. When she catches him he should receive the stimulus we hope will be positively reinforcing.

A new shaping procedure begins once Jack is able to perform the terminal behaviour. At this point the teacher begins to fade the Social Story by requiring him to perform successively more difficult versions of the Social Story until he can eventually solve the problem/distress by simply leaving his seat and discussing a solution with his teacher.

Finally, learning doesn’t occur when the child is in distress. Teachers and parents are often so relieved when the child behaves appropriately that they forget to catch them being good and provide reinforcement. The trick to successfully teaching an kid with Asperger’s how to behave is to use these “good” times as teaching moments. Grab them (not literally for those readers who may have Asperger’s themselves:) and talk about the behaviours they used that were successful. Discuss why they might have been successful and how they might be used in the future. Refer back to them before future events and discuss whether the previously successful behaviour might be worth another shot. If it works, debrief again. Eventually, if a behaviour works often enough it can become a rule and we all know that Aspies love rules.



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