Hey SoS. I've had that happen, on and off, though it would do it for quite a while and then go away for days. Twitching or vibrating? Both? Enough to actually move the thumb? According to my neuro, the "vibration" is, in this case for me, from nerve irritation.I've been diagnosed with carpal tunnel in both wrists/arms, so I wrote it off to something associated with that. I've had clean EMG on both arms, too, so if it was something beyond trapped/irritated nerves, it didn't show--other than the carpal tunnel, that is.Doesn't sound like anything to worry about. You'll find lots of folks here have had similar problems.Mark
