I've been playing professionally for decades, and have no problem playing solo and in chamber settings. And until recently, played with a number of conducted ensembles in contemporary music.But a couple of years ago, I began noticing I was having trouble following a conductor; i.e. I would get lost easily. When I saw a neurologist for a numbness issue, I had all sorts of tests done and my old brain is just fine, but I was low in Vitamin B-12, so I started taking that, and that solved the numbness problem, but not the problem "following."