From what i understand there are two types of ADHD, i was personally diagnosed with ADHD. there are both a physical hyperactivity and a mental hyperactivity. Honestly i think kids can normally filter out background noises unless maybe it's their friends distracting them or something else of interest to them. I was diagnosed with ADHD and i have the same problem your daughter does. I have a hard time concentrating with noise around. I would suggest that you maybe take her in to find out. One thing that you should maybe try, and it may sound kind of weird, children with ADHD have a reverse reaction to caffeine. Maybe sometime you can have your daughter read somewhere in the house, with a noisy tv or radio on, an give her something caffeinated shortly before, and see if anything changes.