I think it's wonderful that they check for both seeing and hearing tests these days. Knowing as early as possible that there is a problem that needs to be addressed is nice, because then it can be taken care of.
My parents were always upset with me when I was growing up, saying I never listened to them. Well, turns out that when I was in my mid-20s, I had problems with my right ear that ended up with my needing to have a permanent T-tube placed, as my eustachian tube was damaged (most likely from a sinus cold, as I had a lot of those then). A hearing test also revealed that I have a 10% hearing loss in both ears. It is a "nerve loss," from what the doctor tells me, and is from birth (meaning it didn't manifest from an infection or something, like the problem with the tube in my right ear did). I am still having trouble with my right ear, and am slowly losing more hearing in that ear.
It would have made things easier for me when I was a youngster if we'd have known about the hearing loss. It makes sense now, when I think about it, that I had trouble with pronouncing certain words. These days, my husband and daughter cannot walk in front of me and talk, nor can they turn away from me and talk, as I have trouble hearing them (it has to do with the range of where the sounds are that I can't hear).
My fear is that, as I get older, I'll continue to lose hearing and will eventually need to learn sign language. I don't mind learning sign language, but I'll miss giving up hearing, if it comes to that, only because I've had hearing in my life. A child born without hasn't had a chance to miss something that he hasn't had. I rely on my husband and daughter to tell me when timers in the kitchen have gone off, and my dog is wonderful at alerting me to visitors. Only problem I have is being able to hear the phone ringing if I'm not nearby. Oh, well.
I pray you find out for sure what your little one's hearing range is; take comfort in knowing that there are terrific resources out there to help. One wonderful idea is to see if you can get him into a baby dance program for deaf or hard of hearing. He'll learn movement and rhythm from the floor vibrations.
There is a dance troupe from China that is made up entirely of deaf dancers; I watched them dance on a "Tube" video, and their dance is absolutely spectacular. In fact, they danced at the 2000 Olympics. I cried as I watched it, knowing these young people were doing a beautiful dance, completely synched with the music--and they couldn't hear the music. But boy, could they pour their heart and soul into their dance. They dance by watching prompters on the side of the stage and feeling the music vibrations through the floor. It's one of the best dances I've seen in a long time.