It started with nausea and vomiting in the morning, followed by insomnia and the annoying sound of clicking in her ears. Marika Bandera, sitting in her east-end Toronto apartment, begins to cry as she recalls how her symptoms gradually got worse over the course of a year. They included everything from shaking hands and blurred vision to burning skin and mild convulsions. Sessions at a sleep clinic, brain scans, an epilepsy test and numerous visits to her family doctor and various specialists in Toronto failed to determine the cause. It wasn't until a trip to Europe that a doctor there suggested her symptoms may be related to extreme electrical sensitivity, or ES, a suspected allergic- like reaction to radio and electrical frequencies associated with cellphones, wireless base stations, computer screens, power lines and common household appliances. Dr. Magda Havas, a professor of the environmental and resource studies program at Trent University in Peterborough, is one of the few trying to track the condition in Canada. Havas estimates as much as 35 per cent of the population may be suffering from moderate ES, with the severe form Bandera experiences affecting 2 per cent. She speculates that ES may have an association with diseases such as multiple sclerosis and diabetes. Havas ... has experimented with filters that help block what she calls electropollution." "I have videos of MS patients who walked with a cane and can now walk unassisted after a few days or weeks with the filters."