The enigma of headaches associated with electromagnetic hyperfrequencies: Hypotheses supporting non-psychogenic...

Although an electrohypersensitivity (EHS) is reported in numerous studies, some authors associate hyperfrequencies (HF)-related pains with a nocebo effect while others suggest a biological effect. Therefore, we aimed to suggest hypotheses about the complex mechanisms of headaches related to HF-exposure. We crossed basic features of headaches with relevant studies (from the year 2000 up to 2018) emphasizing on the HF effects that may lead to pain genesis: neuroglial dysmetabolism, neuroinflammation, changes in cerebral blood perfusion, blood-brain barrier dysfunction and electrophysiological evidences of hyperexcitability. We privileged studies implying a sham exposure (for in vivo studies) and a specific absorption rate lower than 4 W/Kg. HF-induced headaches may involve an indirect inflammatory process (neurogenic, magnetogenic or thermogenic) as well as a direct biophysical effect (thermogenic or magnetogenic). We linked inflammatory processes to meningeal dysperfusion or primary neuroglial dysfunction triggered by non-thermal irradiation or HF-induced heating at thermal powers. In the latter case, HF-induced excitoxicity and oxidative stress probably play a crucial role. Such disorders may lead to vascular-trigeminal activation in predisposed people. Interestingly, an abnormal oxidative stress predisposition had been demonstrated in overall 80% of EHS self-reporting patients. In the case of direct effects, pain pathways' activation may be directly triggered by HF-irradiation (heating and/or transcranial HF-induced ectopic action potentials). Further research on HF-related headaches is needed.