Coincidentally, I read Ginny's comments at the same time that I had to hand
assessment data from three separate occasions for the same student. I shall
use this data to help illustrate some key points. I shall refer to this
student as Ann [not real name].
1] If you take IQ as a measure of intelligence then this may change over
time. As Maragret points out, most psychologists are aware of this, and the
dynamic and interactive development of individuals is well covered in
Michael Rutter & Marjorie Rutter's book, Developing Minds: Challenge and
Continuity across the Life Span. [ISNB 0 14 012569 8]. IQ can go up, or
down, or stay static over time. A number of factors can influnece change.
This variation is seen in Ann's case: a Full-scale IQ of 118 at the age of
nine and a Full-scale IQ of 135 at age 15. [I didn't calculate a
full-scale IQ for Ann as such a score is misleading - see below]
2] In the case of a person with a specfic learning difficulty it makes very
little sense to calculate global measures of IQ, such as Full-scale, Verbal
or Performance IQ. It is much more useful to consider the profile of the
individual. In my expereince, the shape of this profile tends to be
reasonably stable over time, and persists in spite of changes in more global
measures.
For example, Ann's first two assessments reveal an enormous discrepancy
between her performance on two very different tests. On a test of verbal
reasoning her performance places her within the top 1% of the population.
On the other test, an assessment of fine hand-eye control allied with visual
memory, her performance places her within the bottom 4% of the population.
Calculating global measures of IQ means essentially combining these two
scores, with others, to arrive at an average. By doing so all the important
information is lost.
In Ann's case her profile of a slow speed of visual processing and a weak
working memory is clearly evident across all three full assessments in spite
of changes in global measures.
3] What was interesting is that Ann's initial diagnosis was dyslexia, in
spite of good reading skills. It was my judgement that her diagnosis should
be dyspraxia, not dyslexia, and - regretably - I am encountering all too
frequently instances of misdiagnosis or missed diagnoses. This for me is
why a new assessment is often required.
4] I find it is helpful to ask a student about how comfortable they feel
with a previous assessment. Occasionally they have considerable
reservations about how the assessment was handled. In such cases a new
assessment may well reveal quite a different profile, with sometimes a
considerable increase in ability being recorded. In such cases a new
assessment serves a very important purpose. As a rough and ready guide, if
any assessment is carried out by a psychogist who has only a set number of
hours [e.g. 2 hours] time to carry out an assessment there is a danger of
under-estimation.
5] Alexia's point about high achieving students being overlooked is a good
one. It's my expereince that profiling strengths and weaknesses applies
across all ability ranges. It is quite possible for someone to score at the
90th percentile on tests of working memory, but for this high score to still
be formally recorded as a weakness when compared with other scores for
verbal reasoning, which may be at the 99.9th percentile. Once again, my
advice is pay attention to the profile, not global measures.
6] On a point of historical accuracy, the first IQ 'tests' as we know then
today were developed by Binet in Paris. His task was to develop a better
method of determining which children should be assigned to schools for
children with generalised learning difficulties. His success saved many a
child from being assigned to such schools based on the subjective and often
erroneous judgements of teachers. [Echo's of the identification of
dyslexia]. The development of IQ assessments by Binet had nothing to do
with eugenics. Those with a eugenics agenda took advantage of existing
techinques at a later date.
David
David Grant, PhD., Chartered Psychologist
dyslexia diagnosis - a specialist service for students
3 Rosebank Road
Hanwell
London W7 2EW
Tel: 020 8579 1902
e-mail: [log in to unmask]
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