One difficulty I have because of CAPD, is discriminating between "foreground" and "background" noise. If I am talking in a place where several people are talking, or where there is a lot of background noise like humming or buzzing, I find my comprehension "phasing in and out". If I am not trying to interact, this does not bother me much. However, if I am interested in what one person is saying, or trying to respond, it presents problems.
I have an increased tendency to "talk over" people when more than one person is talking. I interrupt and do not realise I am doing it, because I am not always aware who is talking and who is "supposed" to be talking. I was told by a man in my environmental studies class that he was offended by me because I always interrupted him during groupwork. There were seventy students, probably, in the class, and during groupwork most of them seemed to be talking at once. I did not know that this man was trying to talk, and sometimes I did but could not make the connection that his talking was more important than the other background talking.
As an accomodation for this, the Disabled Students' Services at my college allowed my group to take the "group final" in an alternate room. There was still a bit of background noise, but not nearly as much as before.
Another problem in class has been understanding instructions given when there is a lot of background noise. I might miss key words like "not" in an instruction, or not be able to tell at all what I am supposed to be doing. This can be mistaken for "not listening hard enough" or "not paying attention".
I have found, also, that wearing earplugs to reduce the intensity of the input helps me keep calmer in such situations. It does not improve my processing that much, but makes all of the noise seem a lot less significant. I also have earplugs with filters on them, which do not seem to filter out the frequencies of sound which speech takes place on, but definitely help to reduce non-speech "background" sound (which can also be a problem).
When in an environment that I control, I try to allow for the fact that if I am doing something that makes noise, I may not be able to hear a person's speech in a meaningful way.
CAPD.