APD stands for auditory processing disorder. Basically, with APD the ear hears the sound fine but there is a problem with how the brain interprets what the ear said it heard. People with APD may think that others are upset with them when they really aren't. This is because the brain twists what was said so that it is interpreted incorrectly. The audiologist may have the patient repeat things back to them to see if the brain interpreted things right. They may also use different tones and have the patient say "High, Low, High" or something based on what they heard. Not all audiologist do this test so you will need to call around and ask if they do testing for APD.
Hyperlexia is a disorder where the patient is drawn to numbers and letters. The child may learn their numbers and letters at a very early age. However, they may also have problems with word order. This is something that is often seen in people with Asperger's. I don't know how common it is in other people.
Communication with people who have Asperger's, Hyperlexia, and/or APD can be difficult. It has been very helpful for me to know that this is going on with my husband and son. I am now able to kind of unscramble some of what my son says and can understand why my husband thinks everyone is upset with him. Being aware of this has also helped my husband because now, if he thinks someone is upset with him, he knows to ask me if that is the case or not rather than just deciding that they are.
What is a APD Ear test and hyperlexia
A lot of this sounds like what my son did. I had him evaluated by a developmental specialist when he was 2. Because of his age, she said she couldn't 'officially' give the diagnosis (because he had to be 3 or 4 for that) but that he had Asperger's. She also said he had hyperlexia and a checked off some medical terms as well.
I think that with the ear test, you would want to have him tested for APD. A routine hearing exam won't test for this, but audiologists are the ones who do the test. See if you can have him tested for this at the same appointment as his hearing examine.
I would also receommend having him evaluated by a developmental specialist who can check for things like Asperger's, other autism spectrum disorders, and various learning disabilities. They can also do an IQ test.
Based on the symptoms, I would guess that they are going to say he has Asperger's. He may also have hyperlexia and/or OCD.
Depending on where you live, I may be able to recommend someone to do the testing.