It's old age. I'm suffering all kinds of musical mishaps these days (which is why I stopped gigging regularly). Biggest problem - staying in time with very up-tempo tunes (ex. 'Cherokee' at 280 bpm). I try to practice it with a drum machine (BK7m or Alesis Pro 10) to insure beat fidelity and find that I'm having a harder and harder time keeping up. Slow and medium tempo - no problem.
Another problem i'm starting to develop is missing the fingering on exotic or rarely used chords. Also missing notes in fast 'riffs' in solos, etc. So far, no problem remembering tunes (changes) but I'm sure that's next. Oh well, beats being dead.....I think.
chas
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"Faith means not wanting to know what is true." [Nietzsche]