Biology 202
2002 Second Paper
On Serendip

What is a learning disorder and what can knowing more about learning disorders tell us about our own learning? Scientific research has acknowledged that many learning disorders are really just the edge of what is the normal spectrum in human capabilities.(1) Children with reading disabilities differ from one another and from other readers along a continuous distribution.(2) The aptitude to read depends upon fast and precise understanding and decoding of single words.(2) A disabled readers IQ tells very little about their skills. Disabled readers with varying IQ can display exactly the same progress, and neurobiological symptoms. This tells us that the IQ is not a suitable indicator of disability in basic reading skills. That is just one example of the many things that we can learn from people with learning disabilities that we can apply to all people. We will also see that by studying students with dyslexia we can see some of the important brain functions in reading.

For a long time, research in the scientific community in respect to learning disabilities was slim. One problem in recent decades is that scientists have spent a lot of time searching for the basis of the disorder as opposed to the solution. This has created a chasm between the scientific and the educational worlds. Teachers were experiencing frustration with the influence that PhD's and MD's have on their curriculum.(2) Some teachers feel that when help is provided it can be in a non-helpful manner. Researchers don't always take into consideration what it was really like to be teaching.

When we think about learning in a broad scale we think about it as repetition of memorization. On a cellular level learning is the result of change in the strength of a connection due to synaptic activity.(3) At larger levels Hebbian ideals can't really be taken much farther than simple behaviors. We can use Hebbian learning to explain repetitive actions that allow us to learn, say a piece of music. A musician plays a piece of music over and over again, until he/she knows it really well. At this point the synapses that were being used in the musicians brain have physically and chemically changed so that there is now a stronger connection.

Can we explain learning disorders with Hebbian theory? Surprisingly we can. It turns out that dyslexics fail to increase activation in order to make the connections between phonologic structures and sounds.(4) This was discovered in an experiment in which a group of defined dyslexics and a group of non-dyslexics were shown different stimuli while an MRI was imaging their brain. They were given different tasks which were varied to require diverse amounts of visual-spatial, orthographic, and phonological processing. Orthographic processing demands the subject to understand patterns amongst figures. Asking subjects to decide whether or not the letters "t" and "v" rhyme is a phonological task. An example of a task requiring only visual-spatial decisions, is one in which the subject would be shown two series of letters, dDdd and dDdd, and then be asked to acknowledge that they were equivalent.

There are multiple factors to lead to the result of a diagnosis with dyslexia. At this point we are able to clearly pick out students who may have future problems by the first grade.(5) Dyslexia is commonly known as a reading disorder. Dyslexics commonly have trouble reading because they cannot keep track of all the rules of phonological connections to visual and orthographical cues from writing. Another component of dyslexia, which isn't as evident, is a lack of understanding of sound presentations. It seems that many dyslexics have trouble interpreting nuances in rapid sound alterations, limiting their ability to distinguish between sounds.(6) They therefore have a more difficult time differentiating syllables, and fluctuations in voice that indicate context(such as the difference between a question and a statement).

New computer games were developed to train children to read words more accurately. These games require the students to use audio-visual skills to match abstract objects. For example one specific program used in a recent study used different thickness and heightened rectangles in patterns. Two would be shown to the student, and a sound would be played. The student then had to identify which of these patterns was related to the sound.(7) Without knowing it, the student was improving their reading skills. They were training their brain to make connections between symbols and sounds. Reading tests were given to students before and after these computer games. The tests afterwards showed marked improvements in the speed of reading, and accuracy of word identification.(8)

These new forms of computer-based teaching seem to be surpassing the innate learning form. They are teaching the child in a way so that the way the child thinks so that it will be able to continue doing so outside of the classroom. This allows the child to learn in an unconventional way that the regular learning process was blocking. We could possibly examine this blocking as having been caused by the I-function. The I-function requires that the student memorize the coding of language. Dyslexics however, seem to not be able to memorize in this fashion. They can however still recognize patterns, and the computer program teaches them to recognize patterns more accurately.

We can make some generalizations about learning disorders in general after looking at dyslexia. This is possible because dyslexia is "a problem with managing verbal codes in memory,"(5) and the majority of learning disorders are the result of a deficit in phonological understanding, or understanding the codes of language.(2)

There are many other factors that come into play when thinking about learning disorders. There is always the fact that students' minds are occupied with other things. There has to be a limit to how much a person can be learning at one time. The environment may be affecting how that person is learning. If the person needs to keep their mind sharp for another skill, their mind may put that in front of reading in the ranking of importance for survival. Many researchers' have found evidence that dyslexia seems to have economic and familial reasons also.(3)

From our studies of learning disabilities we should take a few things. We should use our new and varied teaching tactics for everyone, to possibly help people that we don't recognize as needing aid. Since learning disorders are just part of the spectrum, what aids a learning disorder may also aid an average learner. We can also take advantage of these deficits to help us better understand the processes in the brain, such as conversion of short-term memory to long-term, complex analyses, and many other questions we have about the brain.

References

1)"The science of literacy; From the laboratory to the classroom."

2)"The Future of Children"

3)"The Hebbian Learning Rule"

4)"Functional disruption in the organization of the brain for reading in dyslexia"

5)"The Dyslexia Institute"

6)"Auditory stream segregation in dyslexic adults "

7)"Neuroimaging Studies of Word Reading"

8)"Plastic neural changes and reading improvement in reading-impaired children"


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