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About Dyslexia
What is dyslexia?
Can treatment help dyslexic
children?
How do I know that my child
has dyslexia?
Common signs of dyslexia
What
is dyslexia?
Dyslexia is the inability to read despite
normal (or above normal) intelligence. It is thought that
as many as one in ten people have this condition which is why it
is the subject of much biological and cognitive research.
The specific cause of dyslexia still remains unclear, although
many different theories exist.
In the past ten years,
functional MRI studies have been
done on dyslexic people to see which part(s) of their brains light up
compared to people who are not dyslexic.
In a German study (reference: PubMed-
PMID: 11786212),
the fMRI revealed that during a silent reading task, there was a
significant
distinction
between the
dyslexic group
and non-dyslexic
group;
 here
they saw an
increased in
activity in the
left inferior frontal gyrus
in the dyslexic
group during
phonological
processing.
Phonological
processing is
the process in
which words are
identified by
identifying
individual
sounds (called
phonemes) that
make up the
words. It is the
inferior cortex of the left frontal lobe that is critically
involved in language function.
In another study (reference:
pnas.240461697), the
fMRI was used to determine
the brain activity when people with and without dyslexia were exposed
to rapid acoustic information. The
non-dyslexic
group showed a
difference in
their left
prefrontal
activity in
their brains in
response to the
rapidly changing
acoustic stimuli
relative to
non-rapid
acoustic
stimuli.
The dyslexic
group showed no
difference. This research showed
that those with
dyslexia
were not able to process sensory input that entered the nervous
system rapidly in the same way as a non-dyslexic person. Interestingly, two of the dyslexic people did
show increased activity in their left prefrontal cortexes after
they received a remediation program.
In the cases just cited, it is the left
frontal part of the brain that seems to be the culprit.
Basically, the left side of the brain is thought to be used for
language and speech, logical reasoning, number skills and
writing. The right side is the spatial side, able to see
the big picture (while the left handles the details). The
right is said to also be the creative, musical side, the side
that can understand a metaphor or a joke. For example,
people who have suffered right-brained strokes can understand
the literal meaning of words, but miss the abstract meaning.
When asked to explain a common proverb such as “a stitch in time
saves nine”, they can only say that it must have something to do
with sewing. Here we can see how the two sides of the
brain must work together to grasp the main idea. The better they
work together, the easier it is for a person to grasp the
complicated task of reading and writing.
The corpus callosum is another subject
of study for the cause of dyslexia.
The corpus callosum is a bundle of
nerves that connects the right and left
hemispheres of the brain; its purpose is
to provide a means for communicating between the two sides.
Studies on the corpus callosum are being done on people who are dyslexic to
try to find a commonality in determining the cause of dyslexia.
Some studies show that the corpus callosum in dyslexic people is
faulty, resulting in miscommunication that impairs understanding
and execution. Consequently, the two sides of the brain do
not work well together.
All in all, studies are still being done to pinpoint the exact
cause dyslexia. What is clear is that the brain does
function differently which impairs the person in reading,
writing and any language based activity. That being said,
individuals with dyslexia excel in other areas that make them unique, they are
just as or more intelligent than non-dyslexics.
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Can treatment help
dyslexic children?
The good news is
that MRI studies have also been done to determine if treatment
can help people with dyslexia. In one study (reference:
pnas.0030098100) a
MRI study was done on 20 dyslexic children (8-12 years old)
before and after a remediation program that focused on oral
language training and auditory processing. After the
treatment, the dyslexic children showed an increase in activity in the
left temporo-parietal cortex and left inferior
frontal gyrus, bringing brain activation in these regions closer to that seen in normal-reading children.
Training improved their reading and oral language performance;
in fact, the more these regions of the brain were activated, the
more the children showed an improvement in their reading and
language ability.
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How do I
know that my child has dyslexia?
If the child does not have any
sensory problems (such as poor eyesight), has adequate
instruction in reading and writing, has an average (or above
average) IQ, and is not reading (or writing) at a level equal to
his or her peers, then it is very probable that he/she is
dyslexic. These children are more visual and less language
oriented.
They may excel at jigsaw puzzles and crafts, usually
having had language difficulties in the early years of their
lives (needing speech therapy). If the child was tested through
their school district (or privately), you really want to know
two things: what is their IQ and what is their reading level.
Note that many school districts don’t recognize that this
condition (dyslexia) exists, or they would have to do something
about it, which is (admittedly) time consuming and thus
expensive.
In any case, the
main problem is that the child can not read and there is no
magic pill that can fix it. To train that brain to read
you must dive (deep) into the English language.
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Common
Signs of
Untreated Dyslexia
Early Years (ages 4 -5)
-
Trouble remembering the names of
the days of the week and months of the year.
-
Trouble following directions
(especially multiple instructions).
-
Has speech problems (usually,
but not always, had many ear infections in their first few
years of life).
-
Trouble making up rhymes.
-
Trouble memorizing words to
songs.
Middle Years (6-9)
-
Reverses letters and numbers
(normally 'b' and 'd', '6' and '9).
-
When reading, may skip words
(strangely, it is usually the smaller, easier words that get
skipped).
-
When reading, may substitute a
word that has the same or similar meaning. For
example, they may see the word "gigantic", but may say "big"
or "large".
-
When reading, may see the first
letter of a word and take a wild guess, out of context,
based on that first letter; for example, they may see a word
like "prairie" and say "palace".
-
When reading, will change
letters within words, such as "calm" to "clam".
-
Forgets to add prefixes or
suffixes when writing. For example, they may forget to
add the 'ed' to make a word past tense.
-
In the classroom, may have
trouble copying from the board.
-
Doesn't always write sounds from
left to right; for example, may spell "to' as "ot.
-
Poor reading comprehension.
-
Trouble memorizing math facts.
-
Delayed in telling time (on an
analog clock).
-
Switches their dominant hand for
some tasks; for example, they may write with their right
hand, but do cartwheels left-handed.
Later Years (10 to adult)
-
Takes poor notes in the
classroom.
-
Has trouble articulating;
jumbles up words or has trouble searching for the right
word.
-
Avoids reading, or reads very
slowly in a monotone voice.
-
Has difficulty with foreign
languages.
-
Writing is very simplistic,
handwriting is usually messy.
-
Trouble organizing.
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