Medical/biological study (experimental study)

Detection-threshold of 50-Hz electric fields by human subjects med./bio.

By: Kato M, Ohta S, Shimizu K, Tsuchida Y, Matsumoto G

Published in: Bioelectromagnetics 1989; 10 (3): 319-327

Aim of study (acc. to author)

To study the threshold intensity for detection of an alternating current (AC) electric field in human subjects at different temperatures and humidities.

Background/further details

The palm and dorsum of the hand were exposed to fields, representing hairless and hairy skin, in order to clarify whether hair movement is critical for field detection.
Experiments were carried out during hot humid weather of July-August and dry cool air of October-November.

Endpoint

hypersensitivity/subjective complaints: perception of local alternating current electric fields

Exposure

- 50/60 Hz
- electric field

Exposure	Parameters
Exposure 1: 50 Hz	electric field strength: 115 kV/m unspecified (October-November experiments) electric field strength: 50 kV/m minimum (august experiments) electric field strength: 60 kV/m (august experiments) electric field strength: 65 kV/m (august experiments) electric field strength: 70 kV/m (august experiments) electric field strength: 80 kV/m maximum (august experiments) electric field strength: 42.5 kV/m minimum (july experiments) electric field strength: 50 kV/m (july experiments) electric field strength: 55 kV/m maximum (july experiments) electric field strength: 10 kV/m minimum (applied in coarse steps to estimate threshold) electric field strength: 30 kV/m minimum (applied in coarse steps to estimate threshold) electric field strength: 50 kV/m minimum (applied in coarse steps to estimate threshold) electric field strength: 70 kV/m minimum (applied in coarse steps to estimate threshold) electric field strength: 90 kV/m maximum (applied in coarse steps to estimate threshold)

Exposure

Parameters

Exposure 1: 50 Hz

electric field strength: 115 kV/m unspecified (October-November experiments)
electric field strength: 50 kV/m minimum (august experiments)
electric field strength: 60 kV/m (august experiments)
electric field strength: 65 kV/m (august experiments)
electric field strength: 70 kV/m (august experiments)
electric field strength: 80 kV/m maximum (august experiments)
electric field strength: 42.5 kV/m minimum (july experiments)
electric field strength: 50 kV/m (july experiments)
electric field strength: 55 kV/m maximum (july experiments)
electric field strength: 10 kV/m minimum (applied in coarse steps to estimate threshold)
electric field strength: 30 kV/m minimum (applied in coarse steps to estimate threshold)
electric field strength: 50 kV/m minimum (applied in coarse steps to estimate threshold)
electric field strength: 70 kV/m minimum (applied in coarse steps to estimate threshold)
electric field strength: 90 kV/m maximum (applied in coarse steps to estimate threshold)

General information

Experiments took place during hot humid weather of July-August and dry cool air of October-November.

Exposure 1

Main characteristics

Frequency	50 Hz
Type	electric field
Waveform	sinusoidal
Additional info	vertical electric field

Exposure setup

Exposure source	capacitive coupling two parallel electrodes/110 x 110 mm, upper electrode connected to a variable transformer
Setup	The upper brass electrode was held 20 mm above the lower aluminum electrode by two insulating posts. The electrodes were movable so that the vertical electric field could be applied on any part of the hand. The lower electrode and the human body were grounded. The lower electrode was in contact with the skin. In the experiments during October-November, hand or forearm was placed inside a small acrylic box (50 x 50 x 50 cm³).

Exposure source

capacitive coupling
two parallel electrodes/110 x 110 mm, upper electrode connected to a variable transformer

Setup

The upper brass electrode was held 20 mm above the lower aluminum electrode by two insulating posts. The electrodes were movable so that the vertical electric field could be applied on any part of the hand. The lower electrode and the human body were grounded. The lower electrode was in contact with the skin. In the experiments during October-November, hand or forearm was placed inside a small acrylic box (50 x 50 x 50 cm³).

Parameters

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	115 kV/m	unspecified	calibration	-	October-November experiments
electric field strength	50 kV/m	minimum	calibration	-	august experiments
electric field strength	60 kV/m	-	calibration	-	august experiments
electric field strength	65 kV/m	-	calibration	-	august experiments
electric field strength	70 kV/m	-	calibration	-	august experiments
electric field strength	80 kV/m	maximum	calibration	-	august experiments
electric field strength	42.5 kV/m	minimum	calibration	-	july experiments
electric field strength	50 kV/m	-	calibration	-	july experiments
electric field strength	55 kV/m	maximum	calibration	-	july experiments
electric field strength	10 kV/m	minimum	calibration	-	applied in coarse steps to estimate threshold
electric field strength	30 kV/m	minimum	calibration	-	applied in coarse steps to estimate threshold
electric field strength	50 kV/m	minimum	calibration	-	applied in coarse steps to estimate threshold
electric field strength	70 kV/m	minimum	calibration	-	applied in coarse steps to estimate threshold
electric field strength	90 kV/m	maximum	calibration	-	applied in coarse steps to estimate threshold

Reference articles

Kato M et al. (1986): Response of sensory receptors of the cat's hindlimb to a transient, step-function DC electric field

Exposed system:

human
partial body: dorsum and palm of the hand

Methods Endpoint/measurement parameters/methodology

hypersensitivity/subjective complaints: perception of local AC electric fields (detection threshold; psychophysical tests)
relative permittivity (capacitance of the hair); humidity and temperature around the forearm; hair movement/vibration

Investigated system:

investigation on living organism

Investigated organ system:

sense organs

Time of investigation:

during exposure

Main outcome of study (acc. to author)

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 (humidity was the main factor for this difference).

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Kursawe M et al. (2021): Human detection thresholds of DC, AC, and hybrid electric fields: a double-blind study
Jankowiak K et al. (2021): Identification of Environmental and Experimental Factors Influencing Human Perception of DC and AC Electric Fields
Kim DW et al. (2012): Origins of electromagnetic hypersensitivity to 60 Hz magnetic fields: A provocation study
McCarty DE et al. (2011): Electromagnetic hypersensitivity: evidence for a novel neurological syndrome
Chapman CE et al. (2005): Perception of local DC and AC electric fields in humans
Lyskov E et al. (2001): Provocation study of persons with perceived electrical hypersensitivity and controls using magnetic field exposure and recording of electrophysiological characteristics
Blondin JP et al. (1996): Human perception of electric fields and ion currents associated with high-voltage DC transmission lines

Detection-threshold of 50-Hz electric fields by human subjects med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

General information

Exposure 1

Main characteristics

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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