The British Medical Journal looked into whether EM "sensitives" could detect mobile phone signals: A colleague who I queried on this matter noted that this study published in March of 60 people who claimed electromagnetic sensitivity and 60 control subject who did not found no ability on the part of "sensitives" to determine whether a signal was present. This is the kind of double-blind study I suggested would go a long way to helping those who have frightening symptoms go through testing to determine what is actually wrong with them, since it's almost certainly not Wi-Fi or cell phones.
In the study, participants were exposed to 900 MHz GSM cell phone signals, sham conditions (no signal present), and a carrier wave for 50 minutes each. The sensitive participants thought a signal was present 60 percent of the time a GSM signal was in use and 63 percent of the time that no signal was in use. Symptoms developed in both cases identically, both in terms of nature and severity. Symptoms reduced following the subjects being told the signal was discontinued whether or not a signal was actually present.