You have two pneumo tubes around your chest to monitor respiration rate. There are two gizmos attached to two fingertips to monitor GSR. Bloodpressure cuff used to monitor blood pressure and pulse rate.
These feed into a little box that is nothing more than a transducer. What is a transducer? A device to convert mechanical input into electrical output (
http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?transducer). The electrical output goes into the computer. The software on the computer (like Polyscore), takes the signals and converts to the rather "scientific" displays, As Seen on TV, no less.
How to counter that process using EMF? Well, there is always the nifty side-effect of an atomic bomb, EMP, that would be sure to create the effect you are looking for. Downside: a lot of people with really, really bad sunburns (think Linda Hamilton in Terminator 2).
Being a movie buff, you may be thinking of that device used in Ocean's Eleven, the one used to shut down the entire electric grid for a city. Upside: the test is stopped. Downside: your mother may be in surgery.
Okay, so let's scale down the weapons a bit. Some form of transmission that would jumble the input into the computer would do the trick. Where to aim it, how to aim it, how powerful, how big, where do you use it from, what about side effects on other computer users? Once that is discovered, all it takes is a shielded cable to protect the transducer/computer connection. Just like the way your cable TV cable uses a shielded jacket so outside/interferring signals are not allowed to affect the cable transmission.
Got your work cut out for you, don't you?