@A MyParkinsonsTeam Member , here's a review article about side of symptom onset and course of symptoms:

Cognitive differences between patients with left-sided and right-sided Parkinson's disease. A review. [Review]
Verreyt N; Nys GM; Santens P; Vingerhoets G.
Neuropsychology Review. (Phone number can only be seen by the question and answer creators) Dec.
[Journal Article. Research Support, Non-U.S. Gov't. Review]
UI: 21956794
Authors Full Name
Verreyt, Nele; Nys, Gudrun M S; Santens, Patrick; Vingerhoets, Guy.
REFERENCE:
At disease onset, patients with Parkinson's disease (PD) typically report one side of the body to be more affected than the other. Previous studies have reported that this motor symptom asymmetry is associated with asymmetric dopaminergic degeneration in the brain. Research on the cognitive repercussions of this asymmetric degeneration has yielded inconsistent results. Here, we review studies that reported on the cognitive performance of patients with left-sided (LPD) or right-sided (RPD) motor symptom predominance. We present evidence that patients with RPD typically experience problems with language-related tasks and verbal memory, whereas patients with LPD more often perform worse on tasks of spatial attention, visuospatial orienting and memory and mental imagery. In general, no differences were found between both groups on tasks measuring attention and executive function. The association between motor asymmetry and cognitive performance indicates that PD does not lead to one typical cognitive profile. The effect of symptom laterality on the cognitive complaints should be considered in the assessment and treatment of each individual patient.
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---So I jumped a bit too soon. Thanks for forcing me to look more carefully at the literature: Some studies find differences as a function of side of symptom onset but others don't. So, if there IS a difference, it's undoubtedly not a strong enough one to make a prediction about what the course of symptoms is likely to be for an individual PWP. I had first looked at a 2015 paper that DID find differences consistent with what the review paper mentions and with what I summarized, but studies aren't consistent.
By the way, a 2014 paper in Medicina Clinica reported that the dominant side (for handedness) was usually the first side affected (particular for those whose initial symptom is resting tremor).

Hope this helps. But it really says that there's no overwhelming strong pattern between the relation between side of symptom onset and course of symptoms or deficits, though some studies find a difference. Most studies are small and assessment methods differ, explaining some of the variability in conclusions. Larger studies often find differences, but the 'statistically significant' (not attributable to chance) findings are still probably unlikely to be strong enough to have predictive utility for an individual PWP.

Mentioned Users

A MyParki...

Right sided pd onset is associated with a better cognitive course and Left sided onset is associated with a better motor course over time in multiple studies. Don't know whether it matters what your dominant side was.

I am sure my dad thought the same as you. We'll all know when we get there!

I am so sorry for your loss. I lost both of my parents a year and a half apart. Mom was 56 and Dad was 60. It is hard to lose them. Sending you a hug.

I have lost both my parents.My brother and sister were. Wonderful.We don't see each other much as we all live far apart,but it is so comforting
To know they are there.(I don't think I ever would have thought that when we were teenagers)I hope they are as much comfort to you