There’s likely to be a neurological examination, which could include pinprick tests (not really a very sharp pin, but just to test whether sensitivity is dulled), reflex tests with the little hammer, checking your balance and coordination, checking whether your eyes can track a moving object - that sort of thing.
I don’t recall having to get undressed for mine, so you should not worry about there being anything embarrassing or intimate, although I did have to remove footwear, so they could test the soles of my feet - though I had reported numbness of my feet. If you’re not experiencing that, they may not test it.
You may prefer to wear something loose and comfortable, as they may want to check range of movement - e.g how far you can lift or bend a leg. If you are in skintight jeans, you may find this a bit impractical!
I think it will be mostly the neuro asking the questions at this stage - he will want to know what sort of symptoms you’ve had, when (roughly - not to exact date and hour) and for how long. Whether there’s anything that noticeably worsens or eases symptoms.
I was asked outright if I drank too much, which I though was a bit of a damn cheek! I answered, as honestly as I could: “Well, how much is too much? Probably, yes, compared to NHS guidelines - Doesn’t everyone? But I’ve never had any concerns about my drinking, and don’t think it would be enough to cause this sort of thing!”
The MRI: an hour sounds on the excessive side. The longest I’ve ever been in there was about 50 minutes, for brain and full spine (right down to tailbone), AND with contrast - which basically means you come out halfway through for them to inject a chemical, and then they do the full set again - so the whole lot…twice!
If, as is much more common for a first scan, they’re just doing brain or head & neck (no contrast), I’d expect 15 minutes is much nearer the mark, and I can’t think why you’d be in there an hour.
You’re not completely incommunicado while you’re in there. It’s very noisy, but you have headphones, so they operators can talk to you (they said helpful things like: “Just one more set, OK?” - so I knew when it was nearly over.) You also get a panic button to push, so that if you need to get out quickly, for any reason, you press it, and they will know to stop the machine and get you out.
If it’s worrying you, I would explain before you go in that urinary urgency can be a problem for you, so they won’t be annoyed/upset if you have to press the button - and also won’t panic that you could be having a heart attack or something! (MRI machines don’t cause heart attacks, but obviously, if you suddenly pressed the button without warning them beforehand you might have to, they would have no idea what was the matter, and might get quite a scare).
I really don’t think it will be an issue, though, as I think you’ll be in and out much quicker.