Detection‐threshold of 50‐Hz electric fields by human subjects

Abstract

The threshold intensity for detection of an AC electric field was studied in human subjects at several different temperatures and humidities. The dorsum and palm of the hand were exposed to fields, representing hairy and hairless skin, in order to clarify whether hair movement is critical for field detection. Experiments were carried out on human subjects (seven men and four women) during hot humid weather of July-August and dry cool air of October-November. Threshold values obtained in the summer were 30-65 kV/m for the hairy skin on the dorsum of the hand, while for the hairless skin on the palm the threshold was greater than 115 kV/m (highest field available due to limitations of the power supply). During the fall, the threshold was much higher than during the summer. We sought possible reasons for the difference and found that humidity was the main factor. Relative permittivity of woman's hair was then estimated by measuring capacitance of the hairs under dry (35% RH) and wet (85% RH) conditions at 20 degrees C. The values of relative permittivity obtained under these two conditions differed by several times the average. The differences in detection thresholds may be attributable to the different relative permittivities of the hairs under dry and wet conditions.

Perception of local DC and AC electric fields in humans

“…Second, an anecdotal report from Cabanes and Gary [1981] indicates that AC field detection is abolished after hair removal. Third, subjects in several studies (AC and DC) referred to a sense of hair movement during field presentation [Cabanes and Gary, 1981;Kato et al, 1989;Blondin et al, 1996]. Finally, Weigel et al [1987] showed that rapidly adapting field receptors [RAF, according to the classification of Burgess et al, 1968] innervating the hairy skin of the cat's paw are activated by AC electric fields.…”

“…Such systems use either alternating current (AC) or, occasionally, direct current (DC). The electric fields that are generated by the transmission lines can be detected by some individuals [Cabanes and Gary, 1981;Kato et al, 1989;Cohen et al, 1992;Blondin et al, 1996]. To date, it is not clear what factors contribute to the ability of subjects to perceive electric fields.…”

“…First, Cabanes and Gary [1981] and Kato et al [1989] observed hair vibration during the presentation of AC fields. Second, an anecdotal report from Cabanes and Gary [1981] indicates that AC field detection is abolished after hair removal.…”

Detection thresholds for 60 Hz electric fields by nonhuman primates

“…Stern and Laties Kato et al [1989] and above 10 kV/m by Graham and Cohen 119851, depending on how exposure occurred, highlights both the importance of exposure conditions and how little is known about EF detection by mammals.…”

60 Hz electric field upregulates cytosolic Ca2+ level in mouse splenocytes stimulated by lectin

“…*Significant difference between two groups (Paired t-test: P < .05, n ¼ 4). current and indirect stimulation by the perception of extremely low frequency (ELF) field on the body surface have been proposed as possible triggers of the effect of ELF EMF on a living body [Weigel et al, 1987;Kato et al, 1989]. While, magnetic field can generally penetrate the cell membrane, the ELF EF cannot because of the presence of the lipid bilayer (plasma membrane) that functions as an electrical insulator [Poo, 1981;Lee et al, 1993].…”