I'm not a doctor, but I believe bulbar ALS is when your speech is effected first before the limbs. My dad has the bulbar form and his limbs are still working pretty well. It's his speech, swallowing, and breathing that are the problem.
Since my mom has been diagnosed I have read and heard the terms "bulbar onset", "bulbar symptoms", and I think as someone said earlier, if it starts with bulbar, then progresses it is referred to as bulbar onset, if it doesn't progress maybe then it is bulbar ALS.
I have been DX with legs onset, but now that I remember it has started with both hands and legs, a year later my speech and swallowing were affected a little bit. So I don't really know, and again it shows that it is really different from a person to another
Hope, There is progressive bulbar palsy. Some Drs question if it is a disease all its own. Some think it is onset. Look at the top of this page at the forum tabs... see PBP, read some of those post too. I was DX PBP then told by the same NeuroMusclular DR that I have bulbar onset. I think, (which is dangerous), that if PBP progresses in to other muscles, then it is considered Onset. So far my main problems are speech, breathing, and choking, which is very scary. I also have COPD which does not help. Just thinking via keyboard. Different doctors different opinions. You are in my prayers as are you all. Sherry