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.