Declining IQ Scores
By Inderbir Kaur Sandhu, Ph.D
My son (age 12.1, dx'd with Asperger's Syndrome at age 8.6) had WISC and
WIAT tests done as a result of research into Autism at a university here
in Melbourne, Australia. He had last been officially tested via a WISC
when he was diagnosed in 2007, and before that at age 5.1 when his
school asked us to get testing organized for him.
His FS WISC scores seem to drop with age: 5.1 = 131, 8.6 = 113, 11.8 =
107. I have wondered at that but was told after the second WISC that
"maybe he was off on the days his scores were low" - but can that be
As for his WIAT test - the first time he's had that test - it came out
with him scoring in the high 130s, and being in the 96th percentile for
Maths Reasoning and 99th percentile for Reading Comprehension. No other
score was below 115. The report stated he is clearly 'gifted' in the two
areas I have mentioned.
What should I do? Should I query with the researchers of the most recent
testing the scoring anomalies? He is a very smart boy, naturally
talented in physics and chemistry, as well as history, public speaking,
music, languages and the performing arts, and has a greater knowledge in
some areas than some of his teachers. Any suggestions?
The question is, can IQ scores change? Yes, it can, though not
drastically in a short period. Especially during infancy and early
childhood, there is a possibility of change in IQ scores frequently.
However, IQ scores begin to stabilize in middle childhood. Furthermore,
by the age of approximately 7 years, childhood IQ scores are found to be
rather good predictors of adult IQ. (Please refer to for more information on
decline or increase in IQ scores).
IQ scores can often vary between one test to another, and in particular,
achievement test scores (WIAT) should not be confused with intelligence
test scores (WISC). However, dramatic change can occur due to any
unusual event (for e.g., injury, trauma, etc.) for IQ scores. In your
son's case, my suspicion is a possible learning disability that has not
been attended to. It is not really possible (with other conditions
unchanged) to have such drop in scores due to “off days” (though the
drop between ages 8.6 and 11.8 is possible). It is a vicious cycle that
when children with disabilities do not receive adequate remediation,
their performance drops due to that disability. Some IQ sub-tests
measure information in which the child has a disability and that causes
the scores to drop. Without intervention, over the years, this gap
becomes larger and stabilizes at a low point.
As he is diagnosed with Asperger's and is also in the gifted range based
on the WIAT, he could be twice exceptional. The scores provided are FSIQ,
so it is hard to tell the subtests that brought his scores down without
the breakdown of the scores. The WISC (I assume the fourth version) does
rely heavily on language skills for many of the tasks and he must have
done well there as he appears to be talented in language (which is also
a strength for children with this condition). For individuals with
Asperger's Syndrome, there may be overlap with anxiety disorders and
with non-verbal learning disabilities. Language skills nearly always
exceed visual motor skills in this group of children. Additionally, you
may also want to check the GAI scores (as opposed to FSIQ).
I think you may need to check with an educational psychologist with
regards to the scores to determine is any learning disability is
present, if at all ( I am suspecting non-verbal learning problems). In
the meantime, work on his strengths (which he appears to have many!) and
help him with the weak areas. Allow some enrichment activities for him.
Remember, these are merely tests to gauge a child's IQ or performance,
usually used a guide to determine a programme that can help maximise the
child's potential. If the child is doing well at school and adjusting
fine, try not to make too much sense of the scores and instead give the
best in what you believe the child needs. As a parent, you would
probably know best what your child needs. Good luck!