Choosing a topic for my research project was quite easy. Dyslexia
naturally presented itself, probably because I have a mild case myself.
I thought of it as a good omen when typing the word “dyslexia” into an
internet search engine, I spelled it “dsylexia”. Of course I was troubled
when the computer reported zero matches, but I caught my mistake, and tried
again, this time more successfully. My dyslexia is really very minor, and
has not presented too much difficulty for me. I often reverse numbers,
which is annoying when dealing with phone numbers, and I am a terrible
speller, which may well be related to my dyslexia. However, people with
severe cases are presented with a serious handicap, making reading, writing,
listening and language comprehension difficult (1,2).
Despite normal intelligence levels, dyslexics often feel stupid and have
self-esteem problems, because of the difficulty they experience in reading
and writing (1).
Dyslexia was first described in 1896 by Pringle Morgan of Sussex,
England, who described a 14 year old boy who “has always been a bright
and intelligent boy, quick at games, and in no way inferior to others of
his age. His great difficulty has been--and is now--his inability to learn
to read.”(5) This was the first description of the
disorder, which exposes the curious problem of intelligent, motivated people
unable to learn basic reading skills. Dyslexia’s most diagnosable feature
is a pronounced disparity between intelligence and scholastic success,
particularly reading.
Reading involves rapid association of symbols (letters and letter
combinations) with the 44 phonemes ( the smallest unit of discernible sound)
of the English language, which must in turn be assembled into a meaningful
whole. People with dyslexia experience difficulty in assembly and dissection
of words into phonemes. Without the ability to consistently see the
relationship
between phonemes and letter combinations, reading is laborious and prone
to errors. Though reading difficulty is the most obvious symptom, dyslexics
experience other handicaps as well. The difficulty dyslexics experience
in word dissection extends to listening comprehension, word decoding problems,
and confusion about paired words (up down, left right, early late)(2,3,5).
There are differences in opinion about what dyslexia actually
is. One advocate web site (6) describe dyslexia
as “a gift” whose symptoms arise from a unique ability to “think in pictures”
It claims that there is no difference between a normal brain and a dyslexic
brain, it is simply a different mode of thought. Another site (1)
describes “scientific watergate,” a conspiracy of scientists to cover
up the real nature of dyslexia, to preserve the theories of the status
quo, at the expense of dyslexia sufferers. It explains that dyslexia is
“an inner ear problem”. This site offers “medical treatment” consisting
of “a combination of inner-ear-improving medications and vitamin-type
substances”.
It claims 75-85% success rate.
A more conventional explanation (5,7)
ascribes dyslexia to malfunctioning portions of the brain responsible for
language and visual processing at their most basic levels. Language is
processed in the brain in a hierarchical series of modules. The upper levels
are responsible for semantics, syntax, and discourse. The lowest level,
called the phonological module, is responsible for processing individual
phonemes, breaking apart and assembling each word. Each word must be parsed
into component phonemes for them to be stored in memory, retrieved, or
processed. This is an unconscious process required for spoken language,
which is required more intensively and more directly for reading, which
requires a conscious breakdown of each word. This is why dyslexics tend
to have more difficulty with reading and writing than speaking and listening,
though these processes are also effected to a lesser degree. Malfunction
of this phonological function in turn blocks the correct function of higher
level modules associated more directly with intelligence. This is the reason
why intelligent people (functioning upper level modules) may have difficulty
mastering simple skills.
With the development of functional magnetic resonance imaging
(fMRI) malfunctions of specific areas of the brain can be tested directly
(5,7). This non-invasive technique allows the monitoring
of metabolic activity of specific areas of the brain, while the brain is
actually working. Normal individuals were asked to do a variety of reading,
writing, and language processing tasks while being monitored. Then these
normal activities patterns were compared to that of dyslexics. Indeed,
portions of the brain had different activity patterns or sizes in dyslexics,
particularly the inferior frontal gyrus, which has been shown to correspond
to phonological function (5).
In addition to supporting the phonological hypothesis,
fMRI studies revealed an unexpected and long discounted theory (7).
For years scientist had blamed dyslexia on a visual disorder, but then
in the last 30 years concluded that the malfunction lay in the language
processing parts of the brain. New fMRI data suggests that visual processing
may after all be involved in dyslexia. While this new evidence suggests
that an image processing defect in the V5/MT portion of the brain may contribute
to dyslexia, it still supports dyslexia’s roots in language processing
problems. There is the possibility that both the language and visual processing
problems are the result of a third, as of yet undiscovered, malfunctioning
region in the brain.
The cause of dyslexia is somewhat a mystery, though there does
seem to be some genetic basis(8). Dyslexia often
runs in families and tends to be more prevalent in males, but no simple
inheritance scheme has been discovered. This could be explained if dyslexia
were a symptom of another genetic problem, which is causative of dyslexia.
For instance it has been proposed that sufferers of dyslexia have a higher
than normal incidence of auto-immune diseases. Maternal antibodies may
injure the developing brain during gestation(9).
Some non-genetic indicators have been described as well. Cerebrovascular
accidents, prematurity, and intrauterine complications are all associated
with dyslexia(8).
No success has been reported with medicinal approaches
to dyslexia (except for the extravagant claims of the sellers of “a combination
of inner-ear-improving medications and vitamin-type substances”) (1).
However many groups report success with education oriented therapies. (3,5,6,9).
These tend to focus on explicit education about and awareness of phonemes,
in reading and writing. Education focused on overcoming dyslexia works
in two ways. First, if started early with phoneme awareness education and
extra reading help, children tend to develop less severe cases of dyslexia.
Second, students with full blown cases of dyslexia can learn to overcome
and work around dyslexia by becoming “compensated dyslexics”. They learn
to consciously decode each word, breaking them down to individual phonemes,
a process which is unconscious for the normal reader. Though this is a
route around dyslexia, it is extremely laborious and tiring. Reading just
takes longer and requires great concentration.
A clear system of diagnosis must be developed to properly help
dyslexics. Now the standard way to detect dyslexics is to wait until they
fall far behind classmates, then ask why. We need to develop a test which
allows us to begin special education and provide extra resources to dyslexics
before they fall behind. The “wait and see if they fail” system is detrimental
to the progress and self-esteem of dyslexic students. Imagine falling two
years behind class mates, and having difficulty reading, never knowing
that it was due to a diagnosable problem. Clearly reliable tests need to
be developed. Unfortunately fMRI, a potentially reliable and definitive
tool for dyslexia detection is expensive and impractical as a screening
device. In the mean time inexpensive paper and verbal tests designed to
reveal problems with phoneme processing and language skills can be a useful
substitute.
The most important thing is educating those who are diagnosed,
both to alleviate the symptoms of dyslexia, and to help provide techniques
for working with and around dyslexia. Those who do not learn how to compensate
for their dyslexia can end up illiterate, and dysfunctional in today’s
society. Dyslexics who learn to overcome their handicaps can easily live
productive and normal live, marked only by a slightly slower reading rate
than non-dyslexics. We can help more dyslexics become “compensated dyslexics”
by providing early detection, and a robust system of education for those
identified.
1) http://www.dyslexiao
nline.com/dyslexia.html#what
From Dyslexia Online
2) http://www.
ldonline.org/ld_indepth/reading/reading-4.html
From Orton Dyslexia Society
3) http://www
.ldonline.org/ld_indepth/reading/nih_report.html
From Learning Disabilities Online
4) http://www.ldonline.o
rg/ccld/ld/ldresearch.html
From Learning Disabilities Online
5) http://www.sciam.com
/1196issue/1196shaywitz.html
From Scientific American Dyslexia article
6) http://www.dyslexia.com/
From Dyslexia.com an advocate site
7) http
://www.kidsource.com/kidsource/content/news/brain7_9_96.html
From a review of an article published in Nature
8) http://www.merck.com/!!ucy831YlLucy831YlL/pubs/mmanual/html/iomhgeeg.htm
From the Merck Manual
9) http://www.interdys.org/
articles.stm#content
From the International Dyslexia Association
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