For months, maybe years, after I was diagnosed with Parkinsons Disease I picked at my memories trying to determine how and when I developed it as if I could go back in time and change it. It is a completely pointless exercise since current research is unclear whether the cause is genetic or environmental . I have mentally dismissed the genetics component so that I don't have to contemplate the implications for my children. That leaves me with plenty of scope for trawling through all the stupid things that I have done in my life that might have been the decisive environmental factor. Could it have been the time when, after an all day drinking session I fell into a deep sleep while I was sat on a bar stool? I toppled backwards, still asleep and my fall was broken by the back of my head hitting the corner of the skirting board. Head injuries do seem to be quite a common factor in the development of PD so its possible. That was 20 years ago and I was diagnosed only five years ago so t