Of course this could be a sign of early Parkinsons disease, but there's a more benign explanation.
I very rarely sign my name.
Forty years ago we signed our names a lot. We wrote checks, we deposited things, some of us did it as a part of our work. In the modern world we enter passwords instead. I haven't written a check in over a year.
Signatures are going the way of the wrist watch. My children may never develop a signature.