Visual and Auditory Basis of Reading
A few years
back, due to the kindness of John Stein's sister-in-law, head of
Meltham primary school, near Huddersfield, we were able to test the vision,
hearing and reading of an entire class of 10 year olds. We wanted to find
out how important the quality of their seeing and hearing was in helping
them to learn to read.
We found that their sensitivity to moving visual stimuli correlated strongly
with their skill at identifying the visual order of letters and the visual
form of words - their 'orthography'. This is because
visual motion is sensed by a special set of visual nerve cells, the magnocellular
system, that plays the main part in controlling visual attention and eye
movements following the letters when reading. If the visual magnocellular
system is weak then eye control during reading will be poor, and the letters
may appear to move around and take the wrong order.
Likewise these children's sensitivity to changes in sound frequency
correlated with their ability to translate letters into their sounds (phonology).
The differences that you hear between letter sounds are because they change
in frequency and loudness, and these changes are detected by the auditory
magnocellular system. Hence if the auditory magnocellular system is weak,
children will tend to confuse letter sounds, hence also their order in
In fact in this primary school class the children's visual and auditory
magnocellular sensitivity accounted for over half their differences in
reading ability. Since we have discovered treatments that can help children
to improve their visual and auditory processing capabilities, this is
very encouraging for the future treatment of dyslexic problems.
But we wanted to make sure that these findings apply to all children in
all types of school, not just in this one school where conditions were
ideal for testing. So we have just finished a study of over 350 children
aged from 7 to 12 years, randomly selected from many of Oxford's
primary and middle schools.
This larger study has confirmed what we found in Meltham, that basic visual
and auditory magnocellular processing abilities do indeed play a dominant
role in determining how well children develop the visual/orthographic
and auditory/phonological skills that are required for reading.
We are now trying to improve the sensitivity of these tests, and to make
them fun for 5 & 6 year olds. This should help us to identify children's
visual and auditory weaknesses when they first start in school, before
they begin to fail at reading. We hope to protect them from the shame,
misery and loss of self-confidence that reading failure so often
brings in its train.