Maxine Young, my audiologist, has a nice note that discusses how to differentiate ADD from Auditory Processing Disorder. Maxine Young specializes in Auditory Processing Disorder and has helped create the program, "Fast Forward".
Apparently a number of executive dysfunctions can get confused with Auditory Processing Disorder (APD).
Max Note 1:
Inattention Difficulty hearing in noise
Distractibility Distracted/bothered by noise
Hyperactivity/Hypoactive Difficulty following spoken directions
Restlessness Poor listening skills
Impulsivity Academic difficulties