OMG -- just googled bilateral idiopathic spinal accessory neuritis and came across your post. I'm about 98% sure this is exactly what I have, my left shoulder went out in late July 2011 and my right shoulder went out a few weeks ago. Both of my lower and mid traps have stopped working. My rhomboids seem to be fine. I've visited with numerous doctors, no one seems to even want to look at my back, they just want to run MRI's/CT's/emg's.... My physical therapist actually broke out his book, went thru numerous range of motion tests, deduced that it was my traps, then looked up the nerves -- why can't MD's do that? Anyway, i have another appointment next monday at the Cleveland clinic - I'm totally fine with out my traps as long as this doesn't progress. I've no history of surgeries or trauma, I do swim quite a bit and have the potential for lyme exposure, so i"m gonna be asked to be tested for Lymes disease. Anything else I should try to get tested for??