At 4, they can't really do Central Auditory Processing Disorder (CAPD) or Auditory Processing Disorders (APD)... usually, "other problems" need to be identified and managed first, because the testing is really intensive and requires good focus. First question we got before they would even do the testing is... any chance of ADD/ADHD (diagnosis or not)? Because unmedicated ADD/ADHD has many of the same symptoms. Also, we've been told the testing isn't geared for kids this young - more like 7 and up.
This is NOT bad news, though. He's 4 now. Lots of testing can't be re-done for 3 years... which puts him at 7. If they can pre-screen for any of this at all, and get "hints" of it, then hopefully you'll end up with a "rule out" statement about Central Auditory Processing Disorder (CAPD) or Auditory Processing Disorders (APD)... which means ** this needs to be re-tested later and a diagnosis made or diagnosis ruled out **. Which means that, in between, school needs to treat him "as though" this is an issue... to what extent depends on the school system where you are.
Don't know if the school Occupational Therapist (OT) will catch sensory issues - but do flag the Occupational Therapist (OT) about the question - even if testing can't be done, might be able to tell you if there's stuff going on that requires a more complete Occupational Therapist (OT) test.
Keep us posted!
(don't really need to tell you that - you're doing good!!)