A major study into the safety of phone masts is being carried out by scientists at the University of Essex.
Dr Ron Williams is monitored as he performs a series of tests
Dr Rod Williams is among more than 260 volunteers who will be tested.
Dr Williams, who used to run a business making millions of pounds, believes the illness which has stopped him working is down to electromagnetic waves.
If researchers find a link, the medical profession will have to recognise that electromagnetic hypersensitivity syndrome exists.
IT specialist Dr Williams, 39, of Braintree, Essex, began feeling unwell seven years ago.
His job meant he has had a high exposure to mobile phones and LCD screens and he originally thought his illness was the early symptoms of the onset of Alzheimer's disease.
"It affects where you can go because if you go to an environment where a lot of people are using mobile phones, I will get a headache immediately after that.
"If you turn up somewhere and have a business meeting you can't make decisions or work you way through issues. It is totally debilitating."
Now he can only use a computer because he has swapped a monitor for a projector and uses an infra-red keyboard.
In the study participants sit surrounded by pyramid-shaped foam which absorbs radio frequencies. The mast sits behind a screen.
Blood pressure and stress levels are monitored while the participants complete basic tasks during four sessions. Neither they nor the researcher knows whether the mast is turned on or off each time.
Dr Stacy Eltiti, of the university's psychology department, said: "Every five minutes we interrupt them and get them to tell us how they are feeling at that time so we can get a picture to see if there are any changes - and we are also doing the physiological measurements continuously."