There seems to be resources regarding "electrosmog" and "electric pollution" along with a long list of symptoms at http://www.lifeenergies.com/index.htm The resources that I glanced at cited studies of electomagnetic energy more in the microwave range and cellphone transmitter range, which is much higher than wireless mic range. I would imagine that the energy issued from a wireless mic would pale in comparision to the energy emitted from the 50 cellphones in the dance hall. It would be interesting if this sensitive person could detect when the wireless was on. TEST: 5 batteries: one charged, others dead, each with hidden labels (A-E). Wireless mic with all displays and indicators concealed. One by one, put a battery in mic for 20 minutes and record all reported symptoms. See if there is a corelation.