Two things: 1) How often do you check her oxygen saturation level? Was this checked at her last appointment? You can actually buy a little portable pulse oximeter for around $150, and then you can check both the oxygen saturation level as well as the heart rate on a regular basis. 2) My mom doesn't have any bulbar symptoms, so I am just repeating what I have read. As I understand it, the extreme outbursts are an upper motor neuron sign and are not necessarily "emotional," so to speak. I think the term is hyperlability, and I also think that I read about a medication that treats this symptom. You might do a search for hyperlability.
I'm sorry that things are so difficult for you. It must be really frustrating to sit by and watch someone who does not want much help.
