Showing posts with label understanding dyslexia. Show all posts
Showing posts with label understanding dyslexia. Show all posts

Thursday, January 7, 2010

Dyslexia Theories May Need To Be Changed



For many years now dyslexia researchers have assumed that the differences in brain activity and structure observed by fMRI scans between groups of dyslexics and non-dyslexics have been caused by dyslexia. I've never seen the question raised about whether these differences could be the result of dyslexia.

Granted, scanning many many babies to determine whether or not the babies have dyslexic brains and then retesting them later after school experiences would be an expensive time-consuming study. That would however help answer the question of whether or not the brain differences first existed in the babies or whether the normal readers were the ones that actually changed.

I've always been impressed with researchers that see unique opportunities to answer difficult questions in a much easier way.The following paragraph is from a story in the New York Times.http://www.nytimes.com/2010/01/03/magazine/03Braille-t.html?pagewanted=2&hpw

'Learning to read is so entwined in the normal course of child development that it is easy to assume that our brains are naturally wired for print literacy. But humans have been reading for fewer than 6,000 years (and literacy has been widespread for no more than a century and a half). The activity of reading itself alters the anatomy of the brain. In a report released in 2009 in the journal Nature, the neuroscientist Manuel Carreiras studies illiterate former guerrillas in Colombia who, after years of combat, had abandoned their weapons, left the jungle and rejoined civilization. Carreiras compares 20 adults who had recently completed a literacy program with 22 people who had not yet begun it. In M.R.I. scans of their brains, the newly literate subjects showed more gray matter in their angular gyri, an area crucial for language processing, and more white matter in part of the corpus callosum, which links the two hemispheres. Deficiencies in these regions were previously observed in dyslexics, and the study suggests that those brain patterns weren’t the cause of their illiteracy, as had been hypothesized, but a result.'

There have been studies about what is called brain plasticity showing that the dyslexic brain can become more like the non-dyslexic brain with reading interventions. That seems to be consistent with the above study.

I'm sure more studies need to be done to confirm that it is the literacy that actually changes the brain rather than dyslexia being a neurological brain difference at least as described by most dyslexia researchers today.

It's likely that the present-day thought is not totally off the mark. But it is also likely that the brain differences so often promoted as being the cause of dyslexia are not entirely correct.

My speculation is that there is an as yet unidentified noise filter function of the brain that makes reading more difficult and is what we call dyslexia. There's been recent research that certainly shows that a likely cause of the phonological processing problems of dyslexics is due to their difficulty separating out sounds in a noisy background. The mechanism behind the difficulty has yet to be discovered.

I have long promoted the concept of visual noise as the cause of visual dyslexia and also the mechanism by which my See Right Dyslexia Glasses remove those visual problems by filtering out the wavelengths of light that caused the visual noise.

For a generalized concept of auditory and visual noise generating the dyslexic's primary assorted problems it is probably best to consider it a higher sensitivity to the noise or a filtering problem.

In the final analysis, it looks like another paradigm of what causes dyslexia is going to be needed.

Wednesday, December 2, 2009

A Different Look at Dyslexia



I wanted to blog today about dyslexia and the fact that when you're talking to someone about dyslexia it is almost necessary for each person to discuss what their concept of dyslexia is before you start. It is very easy when talking about dyslexia to assume that the person you're talking to has the same understanding about dyslexia as you do. This is often not the case.

This isn't meant to be a serious formal discussion about dyslexia but rather an acknowledgment that when you hear that somebody is dyslexic what that means depends a lot upon who says it.
There seems to be a general confusion about dyslexia and its cause. Partly the confusion is caused because of a lack of vocabulary that differentiates dyslexics by their symptoms and partly it is because dyslexia is often written about as if the latest finding applies to all dyslexics and all prior information about dyslexia is now null and void.

Cultural anthropologists and psychologists have both written about how cultures and individuals who lack words for a particular idea or concept act as if they do not exist. Cultures that lack the word for war never get large amounts of people together to fight other large amounts of people. Dyslexics have individual problems that need to be treated in an individualistic way. Thinking of dyslexia as a single condition with a single cause leads to a belief that a particular intervention should benefit all dyslexics. This does not seem to fit the available data.

In much the same way people of the Arctic have many words that differentiate types of snow and use that information for travel, hunting and other uses, dyslexia needs to be broken down into defined subgroups that lead to different effective interventions based on those subgroups.

A numerical scale for ranking the severity of impairment for each subgroup would also be useful as it appears the severity of dyslexic symptoms vary for any individual and may require a combination of interventions for that individual.

In an overly simplified analogy to fertilizers where 3 numbers indicate the amount of nitrogen, potassium and phosphorus in order, such as 23-8-14 or 2-12-10, and the gardener knows which fertilizer ( intervention) to use for a particular plant problem I propose a similar system for dyslexics.

A 0-10 scale could be used where 0 indicates no effect on reading ability and 10 indicates the most severe effect on reading ability.

The order of the numbers would be:

1) processing problems ( treated perhaps by multi-sensory instruction) let us call this Brain Structure Induced Dyslexia.

2) auditory problems ( treated perhaps by phonics instruction) let us call this Hearing Induced Dyslexia

3) visual problems ( corrected by See Right Dyslexia Glasses ) let us call this Visual Dyslexia

In my analogy a dyslexic that was evaluated as 8-5-1 would likely benefit most from processing intervention followed by auditory intervention. This dyslexic would also be able to understand that 1 type of program very well might not be all he or she needs.

A dyslexic evaluated as 1-2-8 might only need visual correction.

I find the idea that there is one answer for all dyslexics to be hype and believe that all the evidence shows that there are many different types of dyslexia that respond to different interventions. I would argue that a primary step in dyslexia research is missing that doesn't evaluate a dyslexic's problems as they relate to different interventions.

Others might suggest that other categories or subcategories need to be included also. I have no problem with that. It does seem fair to include brain, eyes and ears as possible sources of dyslexia symptoms at the minimum based on information available today.

For those who take issue with giving a numerical value to impairments I would like to suggest that eventually those numbers would likely be able to be correlated to success with their associated interventions.

Saturday, November 14, 2009

Dyslexia and Poor Noise Filters


A new piece of information about dyslexia is taking a step from anecdotal evidence to the realm of being considered research-based. The media, as usual, is in the process making it a problem common to all dyslexics. Below is a quote from one of the better reporters who talked to the primary researcher.

"She stressed that not everyone with dyslexia, a learning disorder affecting 5 to 10 per cent of schoolchildren, also has trouble processing sound."

Several dyslexia researchers in the past have suggested that a major contributor to the problem of dyslexia is that dyslexics have problems filtering the audio information necessary for processing when noise is present. Anecdotal evidence has long suggested that many dyslexics have difficulty listening to a speaker when there are other conversations in the background or even a generalized background noise.

While there has been well documented brain structural differences in dyslexics compared to the non-dyslexic population, the resolution of imaging techniques or even autopsy results of dyslexics are unlikely to find the brains mechanism for filtering information anytime in the near future. That doesn't mean that it doesn't exist just that our understanding of how the brain works and what can be imaged is still limited.

The most recent dyslexia study to investigate this phenomena investigated people's ability to become aware of a predetermined background noise when their auditory attention was directed elsewhere. As suspected, dyslexics as a group had a much more difficult time with that task.

Some of the more obvious directions to go with this information is that many dyslexics would benefit from a learning environment without distracting background noise or unnecessary competing conversations. On a practical level that could mean better soundproofing for classrooms and for homework areas or simply seating the dyslexic students in the front of the class closer to the teacher. Another possibility would have the teachers voice relayed to the dyslexic student by headphones.

A harder experiment that is sure to follow is one where an evaluation of a dyslexic's ability to learn phonics when background noise is present to see if auditory noise is contraindicated under that condition. While I haven't seen any results for that experiment, anecdotal evidence suggests that will also be the case for many dyslexics.

I would like to point out that the concept of dyslexics having problems with background noise may help to explain the success and the need for phonological instruction for many dyslexics who appear to have normal hearing. The acquisition of language is not normally developed without background noise present and that is not a problem for the nondyslexic individual. On the other hand, it is fairly easy to understand how a child that does not process background noise well starts to develop phonemic awareness problems from an early age and may benefit from phonological instruction which often takes place on a one-to-one basis in a much less distracting atmosphere.

Unfortunately, probably the most optimum time for the dyslexic child with background noise issues to benefit from an environment without background noise is when they are first learning language and at that age he or she is unlikely to have been identified. Even without the research to prove the necessity, I would suggest that it would be prudent for perspective parents with a high genetic predisposition towards dyslexia to consider trying to maintain a low background noise environment while the children are learning language.

Sometimes I wonder if the apparent increase in the percentage of children with dyslexia with phonological problems is not related to some degree to the relatively new desire to have our lives filled with background noise. It seems that many caretakers of children need to have the background TV or radio always present. The quiet surroundings of the past may have helped lessen dyslexic phonological problems and the increase in background noise in modern society may also have increased the number of dyslexics with phonological problems.

Dyslexia is always difficult subject to write about. Even my post here has not yet mentioned how dyslexia can vary from mild to severe and how phonological problems and background noise are just one small slice in understanding the dyslexia pie.

I would like to encourage the readers of this post to consider a hypothetical situation to demonstrate how people in general vary in their ability to isolate relevant information in a noisy environment. Imagine you are in a large crowded and noisy bar with seven other friends. One more late friend arrives and sees you across the crowded room. Wanting to get the tables attention he starts calling out names from your group one at a time. The chances are that each member of your group will become aware of the new arrival at different times. Some of the group will respond because they will recognize his voice, some will respond because they recognize that each name called out is present at the table, and then others will respond when they hear their own name. Some variations might be depended upon the level of attention the individuals have to other activities or even whether or not the new arrival was expected.

If only one individual at the table was dyslexics he wouldn't necessarily be the last person to respond to the new visitor. It certainly would simplify things if in the above example the dyslexic of the table would always be the last to identify the new arrival. Dyslexia and dyslexia research is just not that simple. It has just not been possible to date to develop a scale with any particular dyslexia symptom and say that anyone falls below this number is a dyslexic.

So while it is true that phonological problems are very common in dyslexics and the idea of dyslexics having difficulties with background noise helps refine the understanding of phonological problems and dyslexia it is still not enough to identify dyslexics because dyslexics are not defined by phonological problems.

It is also true that similar type experiments have found that dyslexics have similar problems with visual noise. It also seems to be a filtering problem of extraneous information. The experiments were done on a computer screen with what some might call varying amounts of TV snow. Dyslexics as a group had problems processing visual information with lower levels of visual noise than the non-dyslexic group. On a conceptual level, the idea of visual noise being a problem for dyslexics is similar to the background audio noise being a problem for dyslexics.

The difference between audio and visual noise problems is that audio problems are most often expressed in verbal language and communication problems while visual problems are expressed in difficulty seeing text. While even nondyslexics can easily relate to background noise as interfering with the ability to develop phonemic and phonological understanding, the concept of visual noise as being a source of reading difficulties is not as familiar.

The visual problems seeing text caused by visual noise are considered visual dyslexia. Because these problems are not as prevalent as the auditory problems they are often discounted. Even the idea of visual noise needs some explanation because most people don't experience visual noise. The closest common experience of visual noise is probably seeing snow on the TV which makes seeing the television picture harder to visualize.

One of the most common visual problems that makes reading difficult for dyslexics is reported to be seeing the text vibrate or in motion. To understand the difficulty of reading text in motion, consider the difficulty of reading while sitting in the backseat of a car driving down a washboard road. Difficulty keeping your eyes on the same line and the task of identifying the individual letters in a word now becomes a problem and reading becomes a chore rather than the easy pleasure it is when reading in a stable condition.

Another common symptom of visual problems when reading is that parts of words or parts of letters are overwritten by visual noise.To understand this type of problem imagine someone vandalizing a freeway sign by overwriting parts of letters or parts of words. The more severe your visual dyslexia is the more the letters and words are overwritten. Reading the sign then becomes more of a guessing game resulting in slower reading and an increased chance of reading errors. The question arises about what is the cause of this visual noise. My opinion is that it is caused by auto fluorescence.

Auto fluorescence is well-documented in the parts of the eye by proteins and many different wavelengths of light. The concept is easy to understand if you consider the path of a single photon which is originally carrying visual information from the object observed. After absorbing the photon by the auto fluorescent protein it is then emitted on a path no longer related to the object observed. The result is that one packet of visual information is removed and changed into a packet of visual noise that is no longer related to the image.

As the visual noise is related to specific auto fluorescent proteins that each are activated by individual wavelengths of light as possible to filter out those wavelengths of light to remove the visual news.

As the cause of the visual noise for visual dyslexia are specific auto fluorescent proteins that are activated by specific wavelengths of light ,it is possible to develop a filter for those wavelengths which effectively removes all of the visual noise. With the removal of all the visual noise the visual problems associated with visual dyslexia are extinguished. I call the universal visual dyslexia filters designed to remove the visual noise caused by auto fluorescence, See Right Dyslexia Glasses. They are available at The Visual Dyslexia Solution.

Dyslexia is of course much more complex than just having problems with auditory and/or visual noise.Individual dyslexics usually have specific coexisting problems that are not limited to only auditory and visual noise. Discussions of the other issues will have to wait another day.