When we were shopping for LTC insurance for my wife, we called an insurance broker who represents many insurance companies, and he was able to sit with us and then recommend an insurance company to meet our needs.
I'm not aware of any LTC policy that would specifically exclude neuro diseases. I believe a standard policy would include them. But you would need to check the fine print before settling. You usually have a month or two where you can get a refund of premiums if you're not happy with anything.
We were shopping for my wife, not me. However, there was no medical exam required, and she only had to answer a few questions to qualify. They're basically trying to make sure you don't already have the most common diseases: cancer, AIDS, diabetes, etc. There weren't any questions about ALS of course. This was two years ago. But I remember at the time I ALMOST was able to qualify even though I had already been diagnosed. I think the only thing that disqualified me was I had just begun using a wheelchair for extended day trips. If I had tried a couple months earlier it would have been no problem. This was astonishing, and I recommend everyone try to get it while their in the diagnosis process or early in the disease. Just make sure you are truthful with all your answers. They usually don't ask the right questions.
-Tom