Well when i run it, i dont allow the character to take any actions for one round, he skips his turn in the initiative order. I do NOT apply any of the following type of conditions as the spell does not state they occur: helpless, stunned, lose dex bonus, loss of ability to make reflex saves, held, etc etc etc. In other words, i give no bonus to attackers vs the character. I guess its treated by me kinda like a daze effect, unable to move or act but no penalties to defense.
None of my players or Dms have ever semed to have a question about that. maybe we are just wrong and we should stray from this understandable method and go to something between the "can deflect arrows" or all the way to "can do nothing" (even breathe? even think?) stances.
or then again, maybe we should rather open our own skulls with claw hammers.