I have experienced this too, but not often. It seems to be at times of high stress or if I am working really hard concentrating.
You have good insite into the causes.
I am so glad you posted this. I have the exact same thing you descibed. I actually spoke to my pdoc about and it's related to the anxiety.
I actually stoped going to Church because if the speaker at the podium makes eye conact I get the stiffness follwed by the jerk. I'm so afraid of someone noticing that I get panic attacks even when I pull into the parking lot just thinking about it.
I get this feeling when I am in a group setting, even at work meetings. If the "power figure" makes eye contact while speaking to the group, I get that "deer in the headlights feeling". I don't think it has ever happened with one on one conversations though. Maybe once or twice.
What are you doing to stop it? I don't know what to do about mine, since it's an uncontrollable feeling. Im sorry you go through this too. I know how frusterating it is. I don't know that anyone notices it's happening though except for the person feeling it.
28 years old
Bipolar II, Panic Disorder, OCD
Seroquel and Klonopin as needed