Dyslexia has not been generally recognized
as a learning difficulty until the last thirty years or so. John
Bradford presents an overview of the latest research on its causes, and
suggests further reading.
The
word 'dyslexia' comes from the Greek meaning 'difficulty with words'.
It needs to be said is that dyslexia is not
brought about by poor parenting. On the contrary, it is the concerned parents
of dyslexic children who have taken the initiatives that have brought dyslexia
to the forefront of the learning difficulties arena. Individual
parents have persisted in pointing out to their children's schools that something
must be wrong when a child of apparently normal intelligence is failing to learn
to read and write. What causes dyslexia,
then? To be quite honest, nobody quite
knows at the moment. There has been a real increase in the amount of research
taking place, and a number of possibilities are beginning to emerge, but the waters
are still fairly murky. The overall picture is that dyslexia can be caused in
two ways: 1. by inherited factors; and
2. by hearing problems at an early age.  Inherited
factors It is clear from all the assessments
that we carry out at Direct Learning that dyslexia is very frequently found in
families, and is often accompanied by left-handedness somewhere in the family.
This does not mean to say that a dyslexic parent will automatically have a dyslexic
child, or that a left-handed child will necessarily be dyslexic. But where dyslexia
does occur, of the children and adults we diagnose, more than 80% have a history
of learning difficulties in their family, and more than 60% have a family member
who is left-handed. With the technical
advances that have come about in brain-scanning in recent years, a lot of work
has been carried out examining the brains of dyslexic people. Bunches of cells
beneath the surface of the brain have been detected which lie on
the surface in the brain of a non-dyslexic person. These groups of cells ought
to have moved to the brain's surface at the time when the brain was developing
in the fetus, but failed to make the journey. They are known as 'ectopic' cells
(like an ectopic pregnancy, where the egg fails to reach the womb and is fertilized
in the Fallopian tube). These ectopic clusters of cells are mainly found in the
left and the front of the brain - the areas which are important for reading and
writing. Another area of the brain - the
magno-cellular system, which deals with our ability to see moving images - is
slightly smaller in the brains of dyslexic people. This makes reading harder,
where the brain has to quickly interpret the different letters and words which
the eyes see as they scan words and sentences. There
are more dyslexic boys than girls, and investigations are being carried out to
see whether a child's mental development is altered by the hormone testosterone.
It is thought that a child's immune system could be affected by an excess of testosterone,
which could lead to problems such as allergies, asthma and dyslexia.
With the use of EEG, where electrodes are fitted to
a person's head, it has been possible to see increased brain activity on the right
side of the brain when a child is beginning to learn to read. Increased activity
is noticeable on the left side in an advanced reader. However, the brains of dyslexic
children show an unusual variation in left- and right-side activity.  Hearing
problems at an early age.
If a child
suffers frequent colds and throat infections in the first five years, the ears
can be blocked from time to time so that hearing is temporarily impaired. The
parents can easily be unaware of this until a doctor actually looks into the child's
ear. This condition is sometimes known as 'glue ear' or 'conductive hearing loss'.
If the difficulty is not noticed at an early stage, then the developing brain
does not make the links between the sounds it hears. This
early learning of sounds and words is fundamental to a child's developing ability
to handle language and text. It causes lifelong difficulties - dyslexia - if corrective
action is not taken at a very early stage. The most common treatment is the insertion
of a tiny tube or grommet into the child's ear. This allows the fluid to drain
off so that the child's hearing is restored. Another treatment is the removal
of the tonsils, which are sometimes the cause of the repeated throat and ear infections.
A combination of both Sometimes
a child has experienced early hearing problems and has also inherited genes which
dispose him or her towards difficulties dealing with the printed word. These children
are often found to be quite severely dyslexic, and need a lot of support through
their school and college years.  Different
types of dyslexia It is thought that
there is a variety of types of dyslexia. At Direct Learning we find that there
is no one pattern which all dyslexic children and adults fit. Some dyslexic children
have good short-term memory, whilst many are really weak in this area. Some have
good skills in math, whilst others really struggle. Some have few problems with
left and right, whilst many experience great confusion. The Dyslexia Adults Link
page on 'Coping with Dyslexia',
has some techniques which dyslexic adults have developed to deal with this confusion.
Learning strategies can make a huge difference
Learning strategies to overcome the difficulties
associated with dyslexia can make a huge difference to the performance of a dyslexic
child or adult. In particular, a 'multi-sensory'
method can really help: this involves teaching children to learn spellings, for
example, not only by hearing and saying the sounds of the letters, but also by
using their visual and tactile (touch) memories by writing the letters in the
air, on the carpet, making them with plasticine or in very large (joined) handwriting
on big sheets of paper. This gives their brain a visual and tactile memory of
the word as well as the memory of hearing the sounds of the letters. Joining the
letters together - in joined handwriting - helps the brain to remember the order
of the letters in a word. Compensating
strengths. There are compensating strengths
for a dyslexic person. Dyslexic children and teens benefit greatly in three important
areas: creativity, physical co-ordination and empathy with others. Teachers working
with dyslexic children and teens see examples of their creative and imaginative
drawings in school, and their skills and pleasure in sports, games, swimming,
skate-boarding and other activities which require the physical co-ordination that
many non-dyslexic children find hard. Every dyslexic child experiences problems
and frustration at school - often including bullying, unfortunately - and they
learn to empathize with other people's experiences of difficulty. John
Bradford
May 1999
 Further
reading about the causes of dyslexia:
 References
and Notes:
Whilst
most psychologists diagnose one broad category of children being dyslexic, or
having a 'specific learning difficulty', Hynd and Cohen argue for the need to
distinguish between dyslexic difficulties brought about by inherited factors and
those brought about by early hearing loss. Dyslexia caused by inherited factors
is referred to as a 'specific learning difficulty of a visual-spatial type', and
dyslexia caused by early hearing loss is referred to as a 'specific learning difficulty
of an auditory-linguistic type'.
•
Dyslexia - Neuropsychological Theory, Research, and Clinical
Differentiation, by George Hynd and Morris Cohen, pub. Allyn and Bacon, Boston,
Mass., 1983. Other
academic references include:
•
Dyslexia - Theory and Good Practice, ed. Angela Fawcett,
pub. Whurr, 2001.
•
Dyslexia, Fluency and the Brain, ed. Maryanne Wolf, pub.
York Press, 2001
• Specific
Learning Difficulties (Dyslexia), by Peter Pumfrey and Rea Reason, pub. Routledge,
1991. | 
