I also have a lot of similarities- 60 years old, diagnosed at 44. Recently (about 3 months ago) I went off Selegeline/ Deprenyl completely after 12 years or so of it being my only PD medication. It served me well and being a tremor dominant sub-type, I believe it slowed down the progression of the
disease for me.
The reason I stopped it was that I was having increasing pain in my joints and very worrisome perceived weakness in my legs that was making me almost completely immobile. I am now gaining back some strength in my legs again and starting to walk and ride my 3 wheeled bike. Also, with the aid of a shot in the knee, I now have very little pain at all, which is an unbelievable relief.
On the down side, now that I am taking sinemet only, I am subject to much more extreme offs and ons.
The latest development is trying out stalevo to smooth out the highs and lows. It is very early in my trial but the stalevo does seem to smooth things out a bit ... however, I have noticed for the first time- a freezing effect. So, that part reminds me of the experience you mentioned IBAL. I have never had that freezing experience before and it is quite alarming. I don't have the disorientation that you mentioned but just feel like I can't move.
I'm going to read through the old posts but if anyone else has had this experience with stalevo- I'd appreciate hearing from them.
I guess if this continues or gets worse, I will go back to sinemet only like you have done reverett123.
By the way, I also have been focusing a lot on the gut- taking probiotics every day and making sure, with laxatives, etc, to avoid constipation.