The published results available in 2005 were insufficient to draw firm conclusions concerning the possible non-thermal effects of radiofrequency fields on the blood-brain barrier (BBB). This critical review deals with 16 articles on this topic published since 2005. The methodological quality of these articles was not equivalent. We therefore analysed the underlying methodologies from both their biological and physical aspects. We conclude that recent studies provide no convincing proof of deleterious effects of RF on the integrity of the BBB, for specific absorption rates (SAR) up to 6 W/kg.
This summary of effects on the BBB is based on 16 research articles, including:
• Three studies in vitro:
Two of these studies [8,9] showed no effect of semi-chronic exposure to GSM or UMTS electromagnetic radiation for SAR values from 0.02 to 1.64 W/kg with validated dosimetry, but with incomplete dosimetry in one case. The third study  reported effects of RF at 915 MHz with modulation and an unusual exposure system, but without dosimetry to determine the SAR.
• Two studies in humans:
Two studies have reported weak variation of circulating protein concentrations in humans, but the methodologies of these methods include several major flaws, particularly as concerns the choice of parameter, making it impossible to interpretate the results. Indeed, the parameter used has not been validated, varies between individuals and is determined in the blood rather than in the CSF [22,23].
• Eleven studies in vivo:
Effects of exposure to RF on the permeability of the BBB and/or neuronal integrity have been sought in vivo, in conditions of acute, semi-chronic or chronic exposure, with a large range of SAR, extending from 0.0018 to 20 W/kg for GSM 900 or TDMA at 1439 MHz or 2450 MHz (continuous and modulated) signals.