Auditory response to pulsed radiofrequency energy

Abstract

The human auditory response to pulses of radiofrequency (RF) energy, commonly called RF hearing, is a well established phenomenon. RF induced sounds can be characterized as low intensity sounds because, in general, a quiet environment is required for the auditory response. The sound is similar to other common sounds such as a click, buzz, hiss, knock, or chirp. Effective radiofrequencies range from 2.4 to 10 000 MHz, but an individual's ability to hear RF induced sounds is dependent upon high frequency acoustic hearing in the kHz range above about 5 kHz. The site of conversion of RF energy to acoustic energy is within or peripheral to the cochlea, and once the cochlea is stimulated, the detection of RF induced sounds in humans and RF induced auditory responses in animals is similar to acoustic sound detection. The fundamental frequency of RF induced sounds is independent of the frequency of the radiowaves but dependent upon head dimensions. The auditory response has been shown to be dependent upon the energy in a single pulse and not on average power density. The weight of evidence of the results of human, animal, and modeling studies supports the thermoelastic expansion theory as the explanation for the RF hearing phenomenon. RF induced sounds involve the perception via bone conduction of thermally generated sound transients, that is, audible sounds are produced by rapid thermal expansion resulting from a calculated temperature rise of only 5 Â 10 À6 8C in tissue at the threshold level due to absorption of the energy in the RF pulse. The hearing of RF induced sounds at exposure levels many orders of magnitude greater than the hearing threshold is considered to be a biological effect without an accompanying health effect. This conclusion is supported by a comparison of pressure induced in the body by RF pulses to pressure associated with hazardous acoustic energy and clinical ultrasound procedures. Bioelectromagnetics Supplement 6:S162-S173, 2003.

Electromagnetic Fields from Mobile Phones do not Affect the Inner Auditory System of Sprague-Dawley Rats

“…(11)], it appears that the site of conversion of RF-field energy to acoustic energy is within or peripheral to the cochlea and that once the cochlea is stimulated, the detection of RF-field-induced sounds in humans and RF-field-induced auditory responses in animals is similar to the detection of acoustic sound. Based on this observation, it is also possible that the inter-799 EFFECTS OF GSM CELLULAR PHONES ON AUDITORY SYSTEM actions between EMFs produced by mobile phones and the hearing system are at the cochlear level.…”

Review of possible modulation‐dependent biological effects of radiofrequency fields

“…The scope of the review was limited to modulations used in telecommunications. The well-established auditory responses [Elder and Chou, 2003] and other biological effects from pulsed microwaves with high peak power [e.g., Pakhomov et al, 2000Pakhomov et al, , 2002Pakhomov et al, , 2003 were not reviewed.…”

Demodulation in Tissue, the Relevant Parameters and the Implications for Limiting Exposure

“…Table 1 summarizes some results for humans and compares these data with the typical characteristics of cellular phones, which cause one of the strongest exposures of humans to pulse-modulated microwaves in everyday life. Additional data about auditory responses to radiofrequency (RF) pulses are given in the review by Elder and Chou (2003). The strong peak power density above 90 mW cm Ϫ2 of the individual pulses is an important criterion for the occurrence of radiofrequency hearing.…”