Oyster- what you describe is called REM behavior disorder (RBD). It has been shown to be a fairly reliable indicator of impending PD. I think it's discussed in the paper I linked to above.

KIbsen- the "death sleep" you describe is the same as a narcoleptic attack. I like the term "irresistable sleep intrusion". I've been doing that since I was 4.
Most people think narcolepsy involves complete loss of muscle control (cataplexy), but only the most severely affected individuals have that symptom. Let me guess- a couple hours after a meal, you feel like you've been drugged. You sleep for a while with raging REM. Then you wake up dizzy.

My paper explains how antibodies to gluten can cause all these problems. I hope to be able to prevent the progression into PD and dementia by increasing awareness of these earlier sleep symptoms.
Believe me, you don't want to get to the dementia stage- it happened to me, and I'm just lucky I'm educated in biology and research, and have learned better than to trust doctors much anymore. I was literally a zombie and they just gave me drugs that made it worse...