I think the key is - did the person who administered the IQ test have any idea why the processing speed was low relative to PRI and VIQ? If the score is artificially low due to things like Zen Scanner mentioned (for instance, a young child might not grasp that time was critical and may have been purposely slow due to perfectionism etc) - the test might not reflect the child's true processing speed, so yes, when the test is given later it might appear that processing speed has improved. If it's due to a physical reason that can be corrected (such as a vision issue) than yes, it can improve once the physical issue has been corrected. If processing speed tested low because of a neurological reason (such as dysgraphia impacting fine motor skills associated with using a pencil) then no, chances are it's not going to improve with age.
*HOWEVER* - stepping onto my soapbox for a minute here - relatively slow processing speed isn't (and shouldn't) keep a child out of gifted programming - instead GAI should be used in place of FSIQ when there is a large discrepancy between PRI/VIQ and Processing Speed.
My ds12 (7th grade) has a relatively low processing speed due to Developmental Coordination Disorder and related fine motor dysgraphia - but his brain isn't slow, it's just his ability to output knowledge quickly. There are literally tons of ways to accommodate slow output and what we've found with our ds is that he performs much better overall when he's in appropriately intellectually challenging and accelerated programming than he does when he's held back due to concerns about processing speed. It may take a bit of researching and advocating on your part but don't think for one minute that a relatively slow processing speed will keep your child out of gifted programs.
The one thing I'd encourage you to do now is to try to get more info (which may mean some more testing) to determine why the processing speed is low relative to other scores. First step would be to go back to the evaluator and ask their impressions. Also look at your ds' overall functioning in school - is he having challenges or is he sailing along without any worries? There are some kids here on this board who have that relatively large dip in processing speed and aren't impacted by it at all, and others like my ds who's dip represents a learning disability or a physical challenge - and *if* there is something to the dip, the earlier you understand what's up and how to accommodate or remediate, the better. I'll caution you that our ds' first IQ test was at 5 and the person administering the test wrote off the processing score as perfectionism and we missed two years of time before we realized there was an issue that needed to be addressed - in the meantime our ds developed severe anxiety related to school.
Best wishes,
polarbear
ps - a bit OT, but fwiw, our neuropsych told us that most of the IQ scores will stay relatively similar over time, but Working Memory is the one area that can be improved with targeted work and also with maturity. We have seen WM scores go up for our ds from 2nd grade to 5th.
