Certainly I have some hearing loss as well, but not yet to the point of needing hearing aids. However my Nolan modular is very noisy so I've use earbuds on my Sena 20S from the get go. I found Plugfones to be comfortable and cheap enough for testing (although not as cheap as others mentioned). I'm not very careful apparently and caught the wire on something getting on or off the bike and pulled out a wire making them trash in only a few weeks. I currently use Shure SE215k earbuds and they are very sturdy (but somewhat costly {$90}, so test with something cheaper). They have a thicker wire which goes up and over your ears (only minor interference with my eye glasses) and my little ears act as strain relief for the cords, additionally I loop the cord from the Sena phone jack up and over the Sena (between the raised antenna and the helmet) and then down behind the Sena to prevent me from accidentally unplugging the cord from the Sena (which I annoyingly did quite often before rerouting the wire). The Shure SE215 have a replaceable cord as well so when I do eventually wreck them (not yet in two years) I can just purchase a new cord. I use the silicone
stepped plugs from Plufones on my Shure earbuds because I don't get a good seal with the foam ones. The silicone plugs come in different colors, so I use orange on my left ear and yellow on my right. It seams silly perhaps, but the colors come in handy when every body is sitting there idling waiting on me to get my plugs in and helmet on.
If you do find the ear buds work for you, you'll no doubt find that you will use the outside mic on the Sena 20s more often. The mic (for some unknown reason
{probably has something to do with rain}) is in the rear in the usb charging/software port, so make sure the little rubber cover is open and cock your head a bit to the right of whoever it is you are trying to hear.
Good Luck Brick!