Oh - for YOUR son... get an Speech Language Pathologist (SLP) evaluation to test specifically for listening in the presence of background noise.
If that test is a problem, get to a Central Auditory Processing Disorder (CAPD)/Auditory Processing Disorders (APD) specialist and ask specifically about the same problem.
Its only been the last few years that tests have even been developed for this stuff, and many Speech Language Pathologist (SLP) and audiology professionals don't know about it yet.
They won't screen you for this unless ADHD and other focus-management issues have been either ruled out, OR are controlled by medications. (inability to manage focus makes it impossible to listen, but that's not an auditory problem!)
