Sunday, 30 December 2012

Visual attention span a major factor in reading speed?

For a few years now there has been almost an orthodox view that reading difficulties, such as Dyslexia are a consequence of what is referred to as a Phonological  processing difficulty.

That there is a visual component has been sort of accepted but ignored by many researchers.

Work by Sylviane Valdois and others has strongly reignited the discussion finally demonstrating that it is possible to test out the role of visual processing independent of phonological contribution.

2014 promises to be a fascinating year in the dyslexia story. Watch this space!

Tuesday, 18 December 2012

slow reading and dyslexia

Slow reading and dyslexia

This is comment on the effects of optimising a computer screen, on a student at what is arguably the top university in the world, diagnosed as dyslexic

The graphs show her eyes struggling with reading on a white, default background and allow comparison with her eyes reading on a computer screen adjusted to her measured needs.

On the white background her eyes showed many sudden moves reminiscent of what is called a nystagmus and her left eye regularly  ‘gives up trying to  fix on the words ‘ to take pictures’.

The two graphs on default show her reading after 15 seconds and after 28 seconds. The visual performance gradually deteriorates.

Using the optimally set screen the eye movements are regular and symmetrical.

On all three graphs the scales are the same.

When we look at the number of fixations (pictures) needed to get through the text, and the reading speed the difference is very stark.
On a default screen

100 words in 111 fixations                                0.9 words per fixation
207 wpm
On her optimised screen

 102 words in 72 fixations                                 1.42 words per fixation.
360 wpm

Effect on working memory?
This student was experiencing increasing fatigue in her reading, when on a white background. More ‘bits of visual data’ were needed to read a sentence and it was taking longer to read this would have made greater demand on her central executive, limiting he ‘working memory’ which in dyslexia assessments is commonly considered to be less the non dyslexic peers.

Ok so how much benefit?

In terms of what matters to the student, more effective reading/ studying
This represents a 74% improvement in speed (reduction in working memory demand?).
The comfort effect is almost impossible to measure.  The stamina effect is very difficult to measure.
She had glasses made to match the colour settings of her optimised computer screen

What did her tutors say?

She is a good mathematician who was struggling but once she got her glasses made exceptional progress. From bottom she became comfortably mid-group!

This was only about the visual target. The opticians had already done their job.

Is this important?  

There was no teaching involved. No phonics. no learning just fitting the task to her eyes. 

If you have difficulties walking, a walking stick can help you walk faster, more confidently and for longer.  

BUT.. the walking stick does not solve your, repair, cure what was causing the slow painful walking. 

If you are assisting someones walking you would make sure that their shoes fit first and give them a walking stick if it helps!

Friday, 14 December 2012

Story of John, a dyslexic young adult

I make no apologies for the technical nature of this blog. John wanted this written down for others to read. It is not his name but in a way it could be the story of thousands of people in this and other countries.
It will continue to be re-enacted across the world until this issue is dealt with logically and effectively.

John did not recognize that he had ‘visual stress’ issues but volunteered for a 1: 1 session to enable him to read more effectively.
He had actually been diagnosed as dyslexic when in Primary school. At secondary school there was a breakdown in his relationships with teachers.  By mid day his reading capability had virtually collapsed.
 He did not wear glasses but had been to an optician when he was 11 years old at the beginning of secondary school, because he was experiencing headaches by the end of the school day.
He was told by the optician that he had good eyesight, in fact exceptional, and was not prescribed glasses.

John had to turn his head sideways to prevent his left eye aching when he read.  Similarly he needed to turn his head slightly sideways when looking at you. 

In class he needed to sit on a particular side of the class to be able to concentrate.  He would regularly be admonished for reasons he did not understand, indeed for actually concentrating because the teachers misinterpreted his behaviour.

At 13 he had left with his parents for Spain, where he no longer attended school.
A quick Visual assessment of John

A rudimentary check on John’s vision identified the following issues.
1.    His left eye was short sighted with a far point (loss of focus) at around 70 cms.

2.   The left eye demonstrated significant astigmatism.

3.   His right eye appeared to have no refractive issues but he had been told that it was ‘lazy’, suppressed.

We do not know what the effect of correct glasses prescription may have had on John’s education.
Too often I hear similar stories from dyslexic undergraduates.
Eye tracking data
A 120 Hz binocular eyetracker was used to assess his visual management during reading

The two graphs above show that the right eye (upper graph) is suppressed and not really’ travelling along the lines of text, the saccades and fixations virtually indistinguishable. 

The graph at the end of this blog report shows that the saccades (rapid moves /straight lines on the graph) are not really happening for the right eye! 

By  the third line the right eye is no longer really moving along the line at all This seems to be influencing the left eye a there appears to be a need to turn his head.

The fixations by the left eye show signs of ‘stress with forward and backward drift ‘during picture taking. The graph at the end of this blog shows that clearly.
Baseline reading scores
Using silent reading as a measure of reading performance

It took 25 seconds to read the text which consisted of.102 words 224 words per second.

Reading text used with academically successful age equivalents the rate was 91 words per minute aloud…Long words more complex syntax,

Rapid automatic naming
149 words per minute

There was no evidence of a need for a larger or smaller font. Actually his optimum font appeared to be 12.

Screen background optimisation

Using his optimal background his silent reading speed doubled to around 440 words per minute.

Reading complex text aloud his reading speed increased to 182 words per minute for text which was with familiar vocabulary.

With complex text using advanced vocabulary and syntax his reading speed, aloud increased to 134 wpm from 91 wpm on a white background. Thus is a nearly 50% improvement in performance.

The graph below shows his eye movements when using his optimum settings.

Both eyes are now moving in a similar but not identical pattern.
The above graph was obtained after an initial use of his optimal background gave the following data.

The top graph, his right eye was gradually turning out and there was consistently a great deal of head movement associated with reading.  This test was followed by a series of reads using only his right eye with the optimal conditions.  This has been used in the past with other students and appears to trigger a change in eye movement management enabling better coordination.

Details of eye movement data.

Using optimal conditions the saccades and fixations are more like those of a fluent reader.
In addition the fixations are taking shorter amounts of time. The average time needed is 285 milliseconds. Using default conditions the time needed was 400 milliseconds.

There were also 41 fixations for 99 words 2.41 words per fixation, whereas on default there were for 100 words, there were 85 fixations or 1.17 words per fixation.

  In other words the system was typically processing twice as many words per fixation.  This is possibly the most important factor influencing the improved fluency heard when someone is reading using optimal conditions.

Friday, 7 December 2012

Questions from A dyslexia specialist

Questions from A dyslexia specialist

What are the symptoms of

A. Imbalance in the field of vision overlap…

1.   The person experiences steady ‘double vision’ when looking at something with both eyes, then it is referred to as diplopia.
2.   The two images move across each other or the whole visual scene appears to be moving rhythmically it is referred to as oscillopsia

  It sounds like this could be described as an orthoptic issue. (eye muscle problem) but on its own that is a bit of a cop out...

If it does not occur when viewing pictures/diagrams but only when reading then it is likely be a task caused issue.  The two images are both having attention given to them but the brain cannot compute them into a single image. Essentially the centre of attention of each eye is too far apart for the system to combine the data. 

 If only when reading then it suggests that prisms (an orthoptic response) might be the answer.

Quite a lot of people find that the double images stop and start, if that happens then it is probably because the brain ‘decides to ignore the data from one eye. It suppresses it.  This can be considered to be associated with the idea of a lazy eye, or Amblyopia. This suppression may be a consequence of an uncorrected focussing problem in one eye.  You need to find out if both eyes are the same in terms of focussing?  If they are not then this will need correcting,

This suppression sometimes appears to be intermittent, dependent on visual task.
If the suppression alternates, then I think this is associated with the rhythmical head movements common in some people experiencing reading difficulties. They get the feeling that they have to ‘fight the words’! That in turn can lead to inner ear effects, nausea, a sense of disorientation, referred to by such as the Davis; I do not consider it to be much of a ‘Gift’ though. A certain Harold Levinson used to supply anti-sea sickness tablets to stop this happening!


 Although you may find that with a suitable computer setting the system is able to combine the images.  Are both eyes the same in terms of focussing?

B) Astigmatisms, please?

These are hard to see in terms of symptoms.  Many people have slight astigmatisms. What they do is to make it take longer for the visual system to create/compute a sharp image compared with a non astigmatic eye... An eye may need to refocus during the fixation and collect more data. If both eyes are the same then this just slows thing down. If one eye is worse then, it can lead the visual system suppressing the data from one eye and that eye then turning away from the object of attention. This can impact on separating the field of vision. Likely to happen when reading more than when looking at graphics targets. (This is associated with the iterative horizontal eye movements involved in reading.

Astigmatism is easily checked for.

1.     Find the nearest point that the student can focus on.
2.      Draw a cross (+) about 5cms both ways on a piece of white paper.
3.     Hold it in front of each eye in turn at the near point.
4.     Tell the person to look at where the lines cross.
5.     If either the horizontal or the vertical line appears fuzzy then there is an astigmatism in that eye.

I often find that candidates omit the middle of words when reading and sometimes also when writing. Should I recommend they are checked for the above two?
I think that what is happening is that their field of view is limited to around 2 or 3 letters. And they need to take several pictures to get through each word.  The correct colour and font size should solve that.  I do not think the points above would cause that.

What happens is they subconsciously guess what the rest of the word is based on the visual cues with the guess usually being in the context of the sentence rather than the paragraph!
Writing is associated with Hand eye coordination. If you put a binocular eye tracker on someone, put a cover on the front so that they cannot see what they are writing and then ask them to write down a sentence.  Then the eye tracker will show you that their eyes are moving as if they were reading the words...the visual memory guides the hands! 
If their eye movements are asymmetrical when they read this appears to lead to asymmetrical (messy) writing

Also: is scotopic sensitivity and eye strain the same thing? 

Sort of... SS was termed by Helen Irlen, and is actually incorrect wording really. 

If someone gets a high score on the Visual stress test (online use it freely!) 

They are likely to be identified by Irlen as having SS.  But they could have other optometric issues. I am also unsure (very) of the protocols employed by Irlen

Eye strain is a term with no actual definition. You could call it reading discomfort. Aetiology, origin of the discomfort, is mixed.

sometimes students who benefit from coloured overlays also mention sensitivity to bright light (artificial and/or sunlight) - is that due to eye strain on top of scotopic sensitivity or is it all the same thing and all comes under the heading of scotopic sensitivity?

Sensitivity to bright light can have several origins.

1.   Corneal problems such as Keratoconus.

2.   Delamination of the cornea/waterlogged cornea associated with undiagnosed/untreated glaucoma

3.     Lack of or limited pigmentation in the back of the eye (the sclerotic)   tends to go with easily sunburnt/ginger/blond hair/ freckles

3.   Poor pupil reflex management. The pupil is too large in bright light, it is not closing enough.

5.     Poor rebuild rate of the pigmentation to capture more light after bleaching.

I am becoming increasingly aware of visual weaknesses when assessing candidates and am trying to make the right recommendations for follow ups with opticians and optometrist. It seems incredibly common for someone to say they and their eyes checked recently and all is fine, but then I find it actually isn't.
This is an issue. Not many opticians really look for these problems. They are not always part of their professional qualifications… they need CPD!

Thursday, 6 December 2012

An Icon in the reduction of Barriers My friend David Morris

The Together! 2012 free festival of Disability Arts, Culture and Human Rights continues this week with a two-day low budget film-makers' workshop and a three-day Film Festival at the University of East London. The film festival is supported by Channel 4, and is programmed in association with ADFDaDaFestKynnysKino and the Picture This Film Festival. For full details see

The Film Festival opens at 5pm on Friday evening (7 December) with a tribute to the late David Morris, beginning with his last film Together!,  commissioned by the UK Disabled People’s Council. David Morris was the Mayor of London’s Disability Adviser, in which role he founded the Liberty Festival and led work on External Inclusion for LOCOG until his sudden death in 2010. In the last two years of his life, David also created an extraordinary body of what he described as “filmed poems”, about his lived experience of disability. These were shot by David’s PAs using a domestic camcorder, and edited by David using voice-activated software at his home in Limehouse. 

On Saturday 8 December the Film Festival begins at noon with Oska Bright  on the Road, featuring films by and starring people with learning difficulties from across the world, including animations and dramas. At 2.30pm there are Films from the East, telling unique, moving and powerful stories from ‘Ordinary East Londoners’ and introduced by Eastside Community Heritage and young film-makers from the Barking and Dagenham Ab-Phab group. Then at 4.30pm the festival continues with Animate!, featuring animated films from the UK, Ireland and Canada. On Saturday evening at 6pm we have the UK PREMIERE of Warrior Champions (Brent Renaud, 2010), the multi-award-winning story of four wounded US service personnels’ 12 month-journey as they fight to compete in the 2008 Beijing Games.

On Sunday 9 December the festival restarts at noon with Artists’ Films and Videos, featuring recent films by leading British and international artists, and continues at 1pm with Short Documentaries; a2.30pm with Dance Films; and Short Dramas at 4pm. The festival finishes at 6pm with Jason Becker: Not Dead Yet (Jesse Vile, 87 mins, 2012), introduced by Disability History Month Director Richard Rieser.