Hello, I would like to add another option to the discussion about PD and CO and other possible causes. Many PWP state that their parkinson-symptoms were first noticed or became visible at the time of an emotional or physical stressfull moment. This can be a joyful moment (like wedding, birth) or a sad moment (funeral, divorce, operation, suddenly losing your work). Exposure to CO is definitely an example of a bad and sad moment of physical stress. As we (PWP) all know, the symptoms of PD get a lot worse in times of stress. If a person wasn't aware yet of his/her PD, because the symptoms were not yet visible or noticable under normal conditions (without stress), the symptoms could seem to be suddenly caused by the stressfull moment, while in fact they were already there, and became suddenly a lot worse and very visible or noticable by the stressfull moment. Greetings, Hans. Hans van der Genugten <[log in to unmask]>