Is it the vibrations?

Noah doesn't go to sleep with a special lovey or blankie. When he's tired he reaches for something electronic and musical. He lays down on it (with the speaker resting on his unimplanted ear) and plays the music over and over again until he drifts off. This is not how he goes to sleep for his regular naps/bedtime but it's an easy way to tell that he's sleepy. I just don't get why he's doing it. I mean as far as we know he has no meaningful hearing in that ear. Or does he? They could never get results for separate ears so I suppose it's possible that he's getting a little something. But even if his hearing was still at the same level as before the implant it would need to be a lot louder than one of those kiddie toys. Noah's unaided sound booth tests were always loud enough to cause me physical pain before he made any response. Is he feeling vibrations? It that normal for deaf kiddos? I just don't know.