Hi C.,
I'm going to be one of those people who tells you that a child under 7 can't be tested....and hate to say this, but I'm going to stick to it. My third son has Auditory Decoding Deficit - what is now just called an Auditory Processing Disorder - and though we knew from when he was 2 and were told he only heard cursory sounds, I am SO glad I waited until he was 7 to have him tested.
The testing was done by Dr Jeanne Ferre in Oak Park, IL, who I see listed below. I didn't realize she was still practicing, but if you can get in to see her - wonderful! She not only gave my son the diagnosis, but pages of handwritten information I could use to help him because IEP guidelines were so different in 2000 when my son was diagnosed, and she knew he would not qualify for services.
The confusion before 7 is that most children don't have a firm enough grasp on language to successfully show a clear cut processing disorder. Even with a good grasp of language these disorders are hard to differentiate between ADHD/ADD, autism, or Asperger Syndrome. If for no other reason I'd wait just to get a good diagnosis.
First though, I would caution looking for a problem. I don't know if this is your only child (sorry, I haven't looked at your profile) but a 5 year old boy can have a lot of concentration issues and difficulty following directions just because he's 5. Before my son was diagnosed I was given this checklist of symptoms, which are still accurate today. I was told he had to display 90% of these things:
--trouble paying attention and taking oral directions, better with visual information.
--trouble paying attention and taking direction when. presented in multiple formats - such as oral and visual together.
--problems carrying out multi-step instructions when given orally, have to have instructions given one step at a time
--appear to have poor listening skills and need people to speak slowly.
--need more time to process information - you can read this as think a long time before giving answers.
--develop a dislike for places with background noises like sports arenas, busy classrooms, concerts, or larger social settings.
--prefer written communication.
--have behavioral problems
My son showed all of these but as he grew and matured - he's almost 17 now - he's learned to ask people to repeat things, take notes, ask to be seated in the front of the class, and knows when he's someplace noisy, he may not catch all of what's said.
What was most striking to me when he was younger, and what prompted his teacher to suggest CAPD testing, was that he was incapable, in any situation - home, classroom, Sunday School, you name it - to accomplish multi-stepped tasks if given all together. If I said, clean up your toys, put on your pajamas, and brush your teeth, he might do one, but more than likely, he would do none of them because he'd forget what they were. To this day, I have to give him instructions one thing at a time.
The thing is, CAPD is more than not following directions or not liking loud noises or crowded loud places. It's a collection of symptoms and a consistency in all arenas - home, school, etc. It's also deceptive because there are days when a person with a CAPD can be extremely capable one day, and have great difficulties the next.
It was explained to me this way by the person who diagnosed my son. She likened it to radio waves. You have a radio on the counter in your kitchen, the radio station is several miles away. You turn on your radio and get the station. But somedays you turn on your radio and you get static. The radio hasn't changed position, nor has the radio station, but something between the station and your home interrupts the signal. Maybe high winds, rain, snow. It's not the radio or the station's fault, but the interruption of something else.
So somedays my son did so well it was scary. But another day he might be tired. Or his allergies were acting up. Or someone was mowing the lawn at the school outside his classroom window and the interruptions got in the way. He could literally forget how to write his name. It's not as extreme now that he's older because he can verbalize it and say - I'm having a bad day, please repeat that, or whatever so he gets the information he needs. But when he was younger, before diagnosis, is first grade teacher labeled him capable yet lazy. We learned the following year that's a very common misconception of CAPDs.
Sorry to be on such a soapbox over this. I hope for your son's sake what you see displayed is normal 5 year old actions. But if not, I wouldn't be too quick to get a diagnosis. You can work with him at home, start to teach him now the skills he may need - like asking to have things repeated, or having his teacher seat him in the front of the room, teach him to keep eye contact with those who are speaking to him. All these things have helped my son and he's not the top of his class, he struggles to learn, but he has the skills to do it and he's doing fine.
Good luck to you!
S.