Hopefully you'll know more after the MRI. those sort of hearing probs are still a bit of a mystery. I did a test just after Christmas & my hearing registered as normal, which seems to suggest that everyone has difficulty following conversation even when the backgound noise isn't particularly loud? Is your tinnitus intrusive, or you only notice when it's quiet? I still notice mine even when it is moderately noisy, although being used to it means I can 'filter out' the ringing noise.
But then I can only speak from my own experience.
hope you get it sorted out.