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IT IS
now widely
accepted that a Dyslexic's brain cells are arranged differently,
or function differently from a normal person's. These brain cell
abnormalities are produced by genetic and environmental factors.
The
brain cells are inherited in the same way as aspects of
personality and physical characteristics, and it is shown that
85 per cent of Dyslexics have immediate relatives with the same
disorder. Thus, Dyslexia is genetically inherited.
Dyslexic boys outnumber girls three to one. The vulnerability of
the male suggests that genes carried on the X chromosome play a
part, but other genes may also contribute.
Some
people's Dyslexia may, on the other hand, be caused by changes
in the brain resulting from illness or accident - before, during
or after birth. These are the environmental factors.
What
ails the Dyslexic's brain?
Whether because of genetic factors or environmental, the brain
of the Dyslexic child gets affected by way of damage,
malformation, poor functioning or a delay in maturation.
Problems such as viral infections, use of drugs, malnutrition
and during pregnancy, labor and delivery, or in the early
newborn period, may give rise to learning disabilities without
mental retardation, by affecting the brain. Such insults on the
brain produce defects in information processing leading to
various learning disabilities.
The
brain- seat of the mind, seat of language
All
the functions of the mind, including the process of learning,
operate by multiple parts of the brain working in tandem. The
brain has two separate halves or hemispheres connected by a
bridge called 'corpus callosum'.
The right hemisphere controls non-verbal and abstract functions,
art and music, intuitions. The left hemisphere controls logical,
deductionistic or mathematical thinking and verbal skills. It is
also responsible for understanding (through
hearing and reading)
and
expressing (through
talking and writing)
of language.
An area towards the front of the brain
(Brock's area) is
in charge of expressing language; a location at at the back (Warwick's
area) is
where understanding of speech that we hear takes place.
There
is a tiny language area in the right hemisphere too.
Visual
and auditory processing
Language functions operate through meaningful interpretations in
appropriate parts of the brain of what is seen (read)
and what is heard- 'visual and auditory processing'.
Dyslexic brains have anatomical differences from normal brains
in the 'language-areas'
described
above, in the bridge between the two hemispheres, and in the
connection involving the visual and hearing pathways in the
brains.
The
anatomical (structural)
deficits give rise to functional
deficits in the processing and expression of information. These
functional deficits manifest as disabilities in the various
aspects of learning.
With
research, the future will reveal why some children learn with
ease while others struggle. The group of disorders we call Learning
Disabilities may then be separated into the various
conditions, each with its own clear-cut cause. |
