Nik - your description of what lower PSI and WMI can do is exactly right when you say, <<I imagine it sort of like trying to use sophisticated new software on an old PC with insufficient RAM - it just doesn't work well. I could be wrong in my understanding but that's what I got from it.>>
For my son, the problem is mostly with PSI - I say, the web page is loading,,,,,,,,,,, and sometimes it just times out!
As far as re-testing - my son's scores didn't go up even when he was on medication, but I have seen many cases where they have. The WISC can actually be given every 12 months, but it is preferable to wait 3 years. If you feel a real need to get the information before the 3 year period, it is within the guidelines to do so. The evaluator could also use a different IQ test such as the Woodcock Johnson Cognitive or the Stanford Binet. But, you the constructs of the tests are all slightly different so you would not know for sure that a change in working memory or processing speed is due to the test or the medication.
