If you mean detached from what is actually going on around you, I have experienced this before. It is like autopilot. Afterwards I do not know what happened when I am in autopilot. As far as not being able to respond in a meeting despite having good ideas has happened to me. It is like I can see what is happening, and how I should respond to it, but I do nothing but sit there non-responsive. I do not know what had happened to me