Non-invasive is what we call using a bipap. Invasive would be having a tracheotomy and the bipap is set to different function settings and basically does the breathing for you. Non-invasive means no trach, bipap is used with mask of some type or as a sip and puff
My husband can't tolerate the bi-pap at night, maybe because he is bulbar onset and has a lot of mouth, saliva, tongue issues, etc. but he wears it during the day watching television. That seems to work well for him.
My husband has loved his since the first night. But he tried on several masks before finding the right one. That seems crucial--that it's comfortable. He kinda looks and sounds like Darth Vadar with it on (he went for "full coverage"), but he sleep so much better! (And so I do too.)