Quite the opposite - it makes UMN voice/swallowing problems worse. As far as I understand it, if you don't have symptoms to begin with, you are fine, but if you do it worsens them.
Mich, I have never had very pronounced pseudobulbar affect (the laughing/crying thing), but it did seem to increase it a bit in me. You'd have to try it to know, really. It isn't habit forming and you could stop anytime, so I wouldn't rule it out just on the possibility. I did take it originally just for energy, but it also seems to have the happy side effect of repressing the mild front temporal lobe issues I get. That could be a placebo effect, of course, but I appreciate it!
For me, especially early on, it became a game of taking the smallest dosage I could function on so that I had the most voice left over to enjoy that function with. Even with the affect on swallowing, I often found restricting my diet a further stage was a better deal than living with the fatigue. It is a trade-off drug, and trade offs are things you just have to find your least cruddy balance with, I think.