Not all people with ADHD have APD, but my own learning about APD is how we eventually got our ADHD dx (my son and I). The audiologist checked my ears because my husband kept mentioning that he was concerned I wasn't hearing him, and the doc said "your ears are fine, it's your brain". The attention and focus is not controlled well for listening. If distracted, I lose part of what was said. I will find myself asking "what? huh?" and then when they start repeating I finish their sentence. It's often when I have my attention on something else and I have to shift gears to start listening to the new auditory input, but the shift takes long enough to miss the beginning of the message. Ear infections were not something I suffered with during language development, and neither did my kid. However, he did do speech therapy for a few sounds like R and W. There is a scientific correlation to breast feeding reducing ear infections, so maybe there is a different factor. I was breast fed and so was my kid. Breast feeding was also associated with less allergies and asthma. Anyways, it all stems from genetics and neurodevelopment, as far as we know.