This is such an important question, as the two conditions often present similarly. So just how do you know if it is ADD or APD? The only way to really know is to test.
There are tests for ADD.
A questionnaire is not a test.
The difference between attention deficit and auditory processing disorder is simple. ADD would manifest in more than one sense, making it global. If the attention issue is auditory only then it is a manifestation of APD and not ADD.
It is also possible that what looks like ADD is auditory fatigue. This is the child who starts the day off okay, but whose performance slides downhill over the course of the day.
Just to keep things interesting, it may not be a question of ADD vs APD. It is possible to have both APD and ADD. This is known as co-morbidity.
It requires a highly skilled audiologist to properly diagnose APD and differentiate between these similarly presenting conditions. Make sure your APD assessment is comprehensive and not simply a screening.
At Hearing Kids we believe you would want to know if your child has APD or auditory fatigue before you trial drugs with harmful and potentially irreversible side-effects for a condition s/he may not even have. We recommend that APD testing be done in the morning to eliminate confusing fatigue with ADD.
To learn more about the Hearing Kids difference read here.
*If you have an ADD diagnosis you MUST take your prescribed medication on the day of the APD assessment for the results to be valid.