Hi,
This interests me as I've been exploring how DS6s fine motor difficulties would impact taking the wisc iv and whether to ask the tester to consider subtest substitution. I know the OP was discussing the wppsi but I think the wisc is relevant.
Trying to understand if the processing speed index (PSI) on the wisc is "supposed" to be incorporating fine motor at all I have been reading a wisc assessment manual. If the wisc intent of timing the response was to time fine motor response, or even to time mental motor planning time, then I wouldn't want to try to avoid ds having that assessed by substituting something that was easier on the fine motor skills. But if the PSI is supposed to reflect only the speed of premotor mental aspects then I do not want his fine motor issues to obscure that. I of course want a score to honestly reflect what it is supposed to so that he's correctly pigeon holed as to needs.
Anyways, here's a couple quotes:
a. "Consider the 4 WISC-IV indexes. Subract the lowest Index from the highest Index....Is the size of the standard score difference less than 1.5 SDs (<23 points)? If yes then the FSIQ may be interpreted as a reliable and valid estimate of a child's global intellectual ability."
b. If there is more than 1.5 SDs between the highest and lowest Index, and the difference between the VCI (verbal) and PRI (perceptual reasoning) is less than 1.5 SDs "then the GAI may be be calculated and interpreted as a reliable and valid estimate of the child's global intellectual ability".
To me this mainstream interpretation of the wisc iv (Flanagan and Kaufman, Essentials of WISC IV Assessment) is saying that of the 4 indexes, the VCI and PRI are the most essential aspects to gifted identification and that a relative weakness in WMI (working memory) or PSI (speed) should not prohibit a child from being recognized as gifted. How they decide that scores specifically further apart than 1.5 standard deviations represent "unfairly" (my word) decreased scores I don't know.
They also note that in gifted children the most common index to be lower is the processing speed. Ie that that some degree of lower processing speed would be considered normal.
There do seem to be quite a few schools/programs that only accept FSIQ. And I would guess that many of those do not use GAI not because they feel WMI and PSI are important (ie that they on purpose want to exclude children with lower working memories or with slightly slower speeds) but because they haven't actually thought about it or don't know they should. A few schools and programs likely have thought it through and did get some expert advice and made a conscious decision that they do not agree with many other experts and that they do only want the children in their program that are exceptionally fast and have exceptional working memories. Likely if one just asks the program/school, they'll have no idea why they only accept FSIQ.
The types of things that seem to lower WMI or PSI are poorer auditory memory, poorer visual memory, poorer working memory (holding info in your head while working with it). For PSI weaker thinking speed, ie needing to mull things over before answering. But a whole host of other things can lower those also: actual visual difficulties such as keeping one's spot on a page, ability to direct attention, ability to maintain intense concentration, ability to search for visual features. How experienced one is at knowing when is the critical moment to listen carefully to verbal info (ie if one is thinking of questions about the instructions when the actual question is read and you are so good at internal focus that you don't hear the question, and you don't get a redo, then speed will be impacted). If a child has been part of a quick moving preschool program they might have more experience with listening to instructions than one who hasn't. And then on the output end to quickly find and indicate a visual choice or make a understandable verbal output. So for example a super quick thinking child who likes to give a background or discuss things or ask a lot of questions could be penalized for time. Even extraneous comments by a chatty child can impact speed. For example, during one of the timed tests perhaps a child immediately knows the answer but first says, "You know, I have a book at home with illustrations that look just like these. Do they say who did these illustrations?", and then points and says "There, that's the answer". As far as I can tell they would be docked by the amount of time they took to say their extraneous sentence because the timer starts at the end of the tester asking the question and ends when the child indicates the answer.
Anyways, if the goal is to access a school/program that only accepts FSIQ then one would want to fully assess all aspects of the child's abilities and personality too that could impact the WMI and PSI, before having them take the WISC or retake the wppsi. There might be things one finds that would suggest a supplemental subtest be used instead of a core subtest. Or there might also be simple things one could say to the child on the day of the test that would help them show themselves best. For some kids it's more effective to say, "this is a test" than "you are going to do some puzzles". For others the reverse would be better at making them do their best.
One of the things that's hit me over and over as I'm reading about wisc assessment is that a well trained thoughtful tester can provide an enormous amount of information about the learning strengths or needs of the child, way beyond just these score number totals. A well trained tester will also get more accurate scores because they will have the ability to check in and see if the child fully understands the task before starting (once the timer is going it's going), they'll better know when they are allowed to remind the child to finish, etc. So no matter the goal, a really experienced good tester is important.
It's not a test where the tester just presents the parts in order and sits back until the child is done. For example, a tester is supposed to watch the child while they do the tests and note how they are planning their approach, what their eye movements are (giving insight to how they are thinking about the task), whether they brush over easy things too quickly, whether they give up easily when it gets hard, the number of words in their response, whether they get to the point or beat around the bush, what types of things distract them, etc. After the child is gone they look at the patterns of responses and how the scores change through the test (ie get over initial worry, get more into it with time, or get tired or bored of testing), patterns of scores, etc. There are very specific moments a tester should say very specific things, prompt a child to continue or ask a child if they can explain more, etc. An inexperienced tester might err on the side of not saying as much because they are unsure of the rules.
Anyways, to the OP maybe one place to start would be make an appointment with the original wppsi tester and see what else they can tell you based on their notes from their testing session back at age 4. A conversation with them or them reviewing their notes might help know where to start with the lower processing score. At the same time try to gauge their experience level, how many wppsis they give a year or whether they recorded insightful comments about your child's learning style versus just having a pure numerical score.
It may also help to talk more to the next tester about your child's particular personality. Ie with my anxious child if the tester says, "Don't forget to go as fast as you can, I am timing this", my child might break down and cry when they don't finish a section in the time allotted, and then because of their emotional distress bomb the rest of the test. Instead the tester says, "Don't forget to take your time, we are timing this but because some of the tasks are designed for teenagers it's normal to not finish every single thing".
