Yes, it's a recognised neurological problem, although there are still plenty of doctors who haven't heard of it. Being unable to decipher speech if there's background noise is only one part of it, there's a multitude of symptoms. It has nothing to do with physical deafness, which isn't to say that the two can't co-exist. It's widely thought that it usually exists in people with dyslexia, and also in people on the autism spectrum. As with both of these, it affects adults as well as children, but for some strange reason is often talked about as if it only affected children. It is likely that it runs in families. The only hospital I know of in the UK which routinely screens for APD is the children's hospital Great Ormond Street in London, although this may have changed by now.
If I were a child today, I'd probably have had my APD picked up at an early age. This is roughly what happened with me. I don't remember much of my childhood, I'm going on what my parents have told me. It seems that I have APD which has been exacerbated by the ME.
First year - repeated hearing tests as I kept on ignoring sounds but would respond to changes in light.
Probably from when I first learned to speak - rapid speech which has always been normal for me. I can't hear that I'm doing it, I hear myself speaking at the same speed as everyone else. Apparently there are gaps between words and I can't hear them.
Age 5 - would come home from school with my hands over my ears, complaining that I couldn't bear the noise.
Up to the age of 19 - keen musician, no problems learning languages, no problems with reading. (High intelligence will have probably compensated for many of the common symptoms.)
Age 19 - first developed ME. Spent the first year with flu-like symptoms being most noticeable, sleeping a huge amount. When I made it to university before I fell ill, had no problems whatsoever with understanding hour-long lectures and wrote huge amounts of notes while listening to them.
Age 20 - suddenly lost the ability to note-take in lectures. I couldn't listen and write, and after a few minutes of all this dense spoken information I couldn't understand speech. I would come out of the lecture exhausted and unable to remember even the basic subject.
Gradually over the next few years - more and more problems with comprehending speech, including being distracted by any background noise (I've never owned a TV for this reason), being unable to gauge how loud I should speak and usually ending up speaking far too loud, going into rapid sensory overload due to sound, increasing difficulties with music (pretty much stopped playing/singing by now), being unable to follow instructions, being unable to remember even a basic phone call from a few minutes later, being unable to do something as basic as dressing while someone is talking, increasing difficulty following TV or film, constantly asking people to repeat what they've said or to tell me what's just been said on TV, having to get them to rephrase things repeatedly until I can understand, extreme difficulty in using the phone if there is any distortion (damn it, will people please get the message that I don't want them to call me on my mobile?!), being unable to follow conversation if there is more than one other person present, needing to see information if I am to have any chance at remembering it, inability to use telephone trees, inability to comprehend someone with a speech impediment or certain accents, sometimes inability to comprehend speech at all. Also hyperacusis, which has largely been successfully treated by white noise therapy, and was likely triggered by getting to the stage of being housebound and being used to living in silence.
I've been incorrectly assessed as having physical hearing problems due to not being able to concentrate in a hearing test, either because of the noise outside the room (which I was assured qualified as "silent", by which they mean "soundproofed to a certain level" rather than actually silent) or because the audiologist kept on talking between beeps and it distracted me so much I couldn't tell what happened next.
I have also developed visual processing problems since acquiring ME. My guess is that it's not that APD causes reading difficulties literally, as so many people claim, but that visual and auditory processing problems are extremely likely to co-exist. The memory issues are far, far stronger with my auditory processing than with my visual processing.