Thanks for your responses.

Kathy they offered me an eye mask but I said no as I would have panicked more if I had something over my eyes that I couldn't remove especially once that head 'cage' goes on. I just closed my eyes and didn't dare open them again & just clutched hold of the alert button very firmly. Mine was no more than about twelve minutes so I guess it wasn't too bad.

I think I'd prefer EMG - although it's not wonderful!