Article

Hearing microwaves: The microwave auditory phenomenon

Authors:
Article

Hearing microwaves: The microwave auditory phenomenon

If you want to read the PDF, try requesting it from the authors.

Abstract

The possible health risk associated with mobile telecommunication devices, used close to the human head and, in particular, effects on the inner ear and hearing of users have been recommended for further investigation by several groups. Recently, a number of projects have been initiated to investigate the structures and functions of the middle and inner ear following exposure to wireless communication radiation. The microwave auditory phenomenon, or microwave hearing effect, pertains to the hearing of short pulses of modulated microwave radiation at high peak power by humans and laboratory animals. Research into this effect is examined

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... Some people may perceive individual pulses of RF as audible clicks, chirping, or buzzing sounds, depending on the pulsing regime and intensity of the frequency and this may play a role on hearing functions. Frey was the first scientist to investigate this phenomenon [10,21] . However, there have been numerous studies on the auditory responses of volunteers today. ...
... Audible sound is produced by rapid thermo elastic expansion, resulting from a rise of 5 x 10-6 oC in a short period of time (10 _sec) [6,13] . However, Lin stated that when human subjects are exposed to rectangular pulses of microwave radiation, an audible sound occurs which appears to originate from within or behind the head [9,10] . Lin also stated that thermo elastic theory is adequate for describing microwave induced sound frequency, threshold of sensation, the influence of pulse width and frequency of the impinging microwave radiation [9,10] . ...
... However, Lin stated that when human subjects are exposed to rectangular pulses of microwave radiation, an audible sound occurs which appears to originate from within or behind the head [9,10] . Lin also stated that thermo elastic theory is adequate for describing microwave induced sound frequency, threshold of sensation, the influence of pulse width and frequency of the impinging microwave radiation [9,10] . ...
Article
Objective: The effects of radio frequency (RF) and microwave radiation on humans have been the subjects of continuous investigation. Since one of the major group of children exposed to RF/microwave radiation includes those living in the employee residential houses of radio broadcasting station, this study investigates whether RF affects auditory systems of children living in the houses close to a 1,062 kHz medium wave radio broadcasting station. Materials and Methods: The study is carried out on twenty-five volunteer children (Boys: 13, Girls: 12) living in employee residential houses close to a broadcasting stations. All subjects in the control group were similar in age, socioeconomic status, but they were not exposed to radiofrequencies. Brainstem Evoked Response Audiometer (BERA) and Pure Tone Audiometry (PTA) were used to measure the effects of RF under investigation on hearing thresholds of the subjects. I-Ill, Ill-V and I-V inter peak intervals were measured in BERA. Hearing thresholds at 250 Hz, 500 Hz, 1,000 Hz, 2,000 Hz, 4,000 Hz and 8,000 Hz were measured in pure tone audiometric measurement. Results: Statistically insignificant sensory neural hearing loss was observed in six children living in residence of broadcasting station at 4,000 and 8,000 Hz frequencies (p > 0.05). However, no difference was observed between the children in the residence of broadcasting station and control (p>0.05). BERA results also indicated no significant differences (p> 0.05). Conclusion: Our results showed no actual hearing loss in the RF exposed children living in employee residential houses. However, we suggest monitoring of hearing function.
... Since the Directive 2013/35/EU [1] distinguishes between sensory effects (vertigo, dizziness, phosphenes, thermal sensations on the skin, or acoustic effects -microwave hearing) [2,3], and health effects with well-defined causes, the exposure limit values (ELV) for sensory effects are defined separately from those for health effects. Ensuring the functioning of structures and living organisms in the presence of EMF can be provided by means specific to the field of bio-electromagnetic compatibility. ...
Article
Full-text available
The paper presents a synthesis of the research performed on the electromagnetic properties and characterization of textile and non-textile materials with applications in shielding and protection from the electromagnetic field. The composite structures of functional textiles intended for protective clothing or general applications for electromagnetic immunity are presented and characterized. There are analyzed composite textiles with amorphous, ferrous or non-ferromagnetic metallic threads manufactured by means of woven and knitting classical technologies as well as materials using non-metallic, electrically conductive powders. The properties of the plain jersey, rib jersey, full and half cardigan fabric, Milano rib, are presented, too. Besides textiles, there are also characterized some composite and non-composite structures using metallic yarns and carbon powder. Another direction of interest relates to the use of textile materials with amorphous metal structure with the scope of achieving a more efficient protection to the electromagnetic fields used in cellular systems and Wi-Fi networks. In addition, a comparative analysis of the methods of characterization of composite structures is made.
... The following sections describe the effective exposure parameters including thresholds for RF hearing, the dependence of RF hearing on acoustic hearing, the mechanism responsible for human perception of pulsed RF fields, and a discussion of the significance of the effect. Reviews on this subject include those by Lin [1978Lin [ , 1980Lin [ , 1981Lin [ , 1989Lin [ , 1990Lin [ , 2001; Chou et al. [1982]; Elder [1984]; Frey [1988]; Postow and Swicord [1996];and Stewart [2000]. ...
Article
Full-text available
ABSTRACT Human auditory perception of pulses of radiofrequency (RF) energy is a well-established phenomenon,that is dependent upon the energy in a single pulse and not on average power density. RF-induced sounds can be characterizedas the perception of subtle sounds because, in general, a quiet environment is required for the sounds to be heard. The sound is similar to other common sounds such as a click, buzz, hiss, knock or chirp. Effective radiofrequenciesrange from 216 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. The fundamental,frequency of RF- induced sounds is independent of the radiofrequency but dependent upon head dimensions. The detection of RF-induced sounds is similar to acoustic sound detection once the cochlea is stimulated; however, the site of conversion of RF energy to acoustic energy is peripheral to the cochlea. The thermoelastic expansion theory explains 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 only a 5 x 10,C temperature rise in tissue at the threshold level due to absorption of the energy in the RF pulse. The experimental weigh-of-evidence excludes direct stimulation of the central nervous system by RF pulses. The perception of RF-induced sounds near the threshold exposure level is considered to be a biological effect without an accompanying,health effect. This conclusion is supported by a comparison of pressures induced in the body by RF pulses and by clinical ultrasound procedures. Key Words: RF hearing, microwave, thermoelastic Elder, page 2
... Millions of people around the world use mobile phones as a communication tool. Computational and experimental studies demonstrated that fifty percent of radiation from cell phones is absorbed by the hand or the head [1]. Therefore, the possible health risk associated with mobile telecommunication devices, used close to the human head and in particular, effects on brain functions and the inner ear have been recommended for investigation [2,3]. ...
Article
Full-text available
Possible health risk associated with mobile telecommunication devices can be classified by dosimetry of the exposure. Dosimetry is an important but hard issue that is estimated by computational or experimental methods. Signal emitted from the mobile phones in different modulations such as talking or listening changes, so the level of exposure is different in different modulations. Talking and listening modulations of two different models of GSM 1800 MHz mobile phones were measured while modulated human speech, also pure tone with the intensity of 0-120 dB and frequency in between 125-8000 Hz applied through the phone. Our aim was to detect the minimum intensity of tone that changes the modulation of mobile phone from non-speaking mode to speaking mode, because it is known that there is parallel increase on the stress of the living things if the intensity of the sound is increasing. The data may be used for monitoring the daily exposure of the people using mobile phones, also defining the level of exposure at the laboratory experiments. It may be useful for the people for having individual precautions on using mobile phones in their daily lives.
... The following sections describe the effective exposure parameters including thresholds for RF hearing, the dependence of RF hearing on acoustic hearing, the mechanism responsible for human perception of pulsed RF fields, and a discussion of the significance of the effect. Reviews on this subject include those by Lin [1978Lin [ , 1980Lin [ , 1981Lin [ , 1989Lin [ , 1990Lin [ , 2001; Chou et al. [1982]; Elder [1984]; Frey [1988]; Postow and Swicord [1996];and Stewart [2000]. ...
Article
Full-text available
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 10000 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 x 10(-6) degrees C 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.
... However, research should also be focused on hearing functions of persons working or living in RF/microwave fields such as radio broadcasting, TV transmitting stations, and radar because some people may perceive individual pulses of RF as audible clicks, chirping, or buzzing sounds, depending on the pulsing regime and intensity of the frequency. Frey was the first to investigate this phenomenon (1,2). Since then, there have been numerous studies on the auditory responses of volunteers. ...
Article
The effects of radio frequency (RF) and microwave radiation on humans have been the subject of continuous investigation. Clinical investigations related to occupational RF/microwave exposure have been reported by investigators (1). Since one of the major groups occupationally exposed to RF and microwave radiation includes those working in radio broadcasting and TV transmitter stations, this study investigates whether RF affects auditory systems of people exposed to RF. The study is carried out with people working in radio broadcasting stations and living in employee residential houses close to the broadcasting stations. All subjects in the control group were similar in age, work regime, socioeconomic status, and lack of experience in working with RF sources. Brainstem Evoked Response Audiometer (BERA) and Pure Tone Audiometry (PTA) were used to measure the effects of RF under investigation on hearing functions of the subjects. In BERA measurements, I-III, III-V and I-V interpeak latencies were evaluated. In pure tone audiometric measurements, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and 8000 Hz frequencies of hearing threshold were measured in subjects of experimental and control groups. Interpeak latencies and bone conduction hearing thresholds of subjects in the experimental group were compared with those of the control group. BERA results showed that I-III, I-V and III-V interpeak latencies of people occupationally exposed to RF were not higher than subjects in control groups (p>0.05). Results of BERA indicated no statistically significant differences between exposure and control subjects. In audiometric evaluation, hearing threshold of people occupationally exposed to RF were found higher than the control group subjects for frequencies of 4000 Hz and 8000 Hz in terms of bone and air conduction of right and left ear (p < 0.01). The results of traditional audiometer indicated that RF promotes sensorineural hearing loss and affects cochlea parts related to 4000 Hz and 8000 Hz. These findings may have immediate implications and considerations for workplace safety in order to provide an occupationally safe environment to employees working in such settings.
... Although the mammalian ear has no sensitivity to electromagnetic waves at microwave frequencies (300 MHz-300 GHz) human auditory perception of radio frequency energy has been reported since the 1940s [43][44][45][46][47][48]. It is now widely accepted that the auditory perception of microwaves is a result of thermoelastic expansion [49,50]. ...
Article
Full-text available
Large numbers of bats are killed by collisions with wind turbines, and there is at present no direct method of reducing or preventing this mortality. We therefore determine whether the electromagnetic radiation associated with radar installations can elicit an aversive behavioural response in foraging bats. Four civil air traffic control (ATC) radar stations, three military ATC radars and three weather radars were selected, each surrounded by heterogeneous habitat. Three sampling points matched for habitat type and structure, dominant vegetation species, altitude and surrounding land class were located at increasing distances from each station. A portable electromagnetic field meter measured the field strength of the radar at three distances from the source: in close proximity (<200 m) with a high electromagnetic field (EMF) strength >2 volts/metre, an intermediate point within line of sight of the radar (200-400 m) and with an EMF strength <2 v/m, and a control site out of sight of the radar (>400 m) and registering an EMF of zero v/m. At each radar station bat activity was recorded three times with three independent sampling points monitored on each occasion, resulting in a total of 90 samples, 30 of which were obtained within each field strength category. At these sampling points, bat activity was recorded using an automatic bat recording station, operated from sunset to sunrise. Bat activity was significantly reduced in habitats exposed to an EMF strength of greater than 2 v/m when compared to matched sites registering EMF levels of zero. The reduction in bat activity was not significantly different at lower levels of EMF strength within 400 m of the radar. We predict that the reduction in bat activity within habitats exposed to electromagnetic radiation may be a result of thermal induction and an increased risk of hyperthermia.
Article
Full-text available
The human body has unique electrical characteristics. These characteristics have been investigated in various studies in human-computer interaction (HCI) and related research fields. Such studies include applications for using the body as a conductive lead for transmission or electric field sensing and activating human muscles or organs. However, electricity is not completely safe for the human body; therefore, to avoid harming users, careful consideration is essential when developing such devices. The knowledge required for such consideration is spread throughout a large number research fields, and it can be difficult for researchers in the HCI field to comprehend all of them. The purpose of this article is to support researchers in developing systems that apply electricity to the human body and to serve as a basis for further research. This article reviews previous research pertaining to HCI in which users come into contact with electricity. In addition, considerations of how and where this type of research can be expanded, along with guidelines grounded in other fields for designing systems safely and addressing ethical concerns, are presented. An understanding of the field and of the related safety issues will enhance the understanding of limitations and potential and can clarify the design space.
Article
In late August 2017, media out lets began reporting on the U.S. State Department's disclosure that Havana-based U. S. diplomats were experiencing health issues [1]-[5]. Their residences were described as having been targeted with bursts of sound waves. Diplomat ic staff and family members have repeatedly reported hearing loud buzzing or scraping sounds. Symptoms include severe hearing loss, headaches, ringing in the ears, nausea, and problems with balance or vertigo, which are suggestive of a connection to the inner ear apparatus within the human head.
Book
From engineering fundamentals to cutting-edge clinical applications This book examines the biological effects of RF/microwaves and their medical applications. Readers will discover new developments in therapeutic applications in such areas as cardiology, urology, surgery, ophthalmology, and oncology. The authors also present developing applications in such areas as cancer detection and organ imaging. Focusing on frequency ranges from 100 kHz to 10 GHz, RF/Microwave Interaction with Biological Tissues is divided into six chapters: Fundamentals in Electromagnetics—examines penetration of RF/microwaves into biological tissues; skin effect; relaxation effects in materials and the Cole-Cole model (display); the near field of an antenna; blackbody radiation and the various associated laws; and microwave measurements. RF/Microwave Interaction Mechanisms in Biological Materials—includes a section devoted to the fundamentals of thermodynamics and a discussion on energy and entropy. Biological Effects—investigates the effects of radio frequency fields on the nervous system, the brain and spinal cord, the blood-brain barrier, and cells and membranes. Thermal Therapy—includes a description of applicators and an extensive discussion on the foundation of dielectric heating and inductive heating. EM-Wave Absorbers Protecting the Biological and Medical Environment—investigates materials for EM-wave absorbers from both a theoretical and applications perspective. Special attention is given to ferrite absorbers. RF/Microwave Delivery Systems for Therapeutic Applications—begins with the fundamental features of major components used in RF/microwave delivery systems for therapeutic applications. New research towards the development of future measurement techniques is also presented. The book features problem sets at the end of each chapter, making it an excellent introduction for bioengineering and engineering students. Researchers, physicians, and technicians in the field will also find this an excellent reference that offers all the fundamentals, the most cutting-edge applications, and insight into future developments.
Conference Paper
Within a few years, the use of mobile - called "cellular" - phones exploded all over the world. More than 600 millions of them were sold in 2004! To ensure proper service, base stations must be installed in increasing numbers and many people strongly object to seeing antennas sprouting up in their close neighbourhood! So far, no one has been able to definitely prove that radiation from cellular phones could be harmful, but there is no proof either that it is harmless. Some aspects must still be clarified, and large research projects were initiated to understand and avoid potential hazards (J.C. Lin, 2001). But the problem must be considered in its proper perspective: the concepts of "electromagnetic pollution" and "electrosmog" were coined rather recently, while man-made electromagnetic radiations have been around for more than a century! And natural radiation is essential for all life on Earth! For many years no one questioned the use of waves for radio and TV broadcasting. Does the use of low-power cellular phones create hazards that were not present before?
Article
The biological effects of microwave radiation on health are discussed. The high specific absorption rate (SAR) induced by microwave radiation raises the temperature of brain to 42°C, it increases the blood-brain barrier (BBB) permeability for substances excluded from brain parenchyma. The BBB protects the brain from foreign substances by blocking their passage from the blood which can be hazardous. For the evaluation of scientific literature the experimental and observational techniques, methods, data analyzed and exposure conditions should be completely objective. The detail published description of methods and materials should be given to meet the objective requirement.
Article
Full-text available
The purpose of this paper is to present the experimental device and the work in progress performed in search for objective organic correlation of damage to hearing, examining possible acoustic otofunctional effects on the cochlear epithelium of the rat due to exposure to microwaves (900 MHz). Two experiments using male Sprague-Dawley rats were carried out with a far-field exposure in a cubic chamber. No statistically significant evidence was obtained at both specific absorption rate (SAR) values. The exposure system and the diagnostic apparatus are extremely useful to investigate a potential effect on the auditory system: however, with the parameters applied in these experiments, no evidence was observed.
Article
Full-text available
This paper presents a numerical analysis of the thermoelastic waves excited by the absorbed energy of pulsed microwaves in a human head. First, the authors calculate the distribution of the specific absorption rate using a conventional finite-difference time-domain (FDTD) algorithm for the Maxwell's equation. They then calculate the elastic waves excited by the absorbed microwave energy. The FDTD method is again applied to solve the elastic-wave equations. The validity of the analysis for elastic waves is confirmed through comparison of the FDTD results with the analytical solutions in a sphere model. Two anatomically based human head models are employed for numerical calculations. The waveforms of the calculated pressure waves are different from the previously reported ones. It is especially shown that the surface heating is important in exciting the fundamental mode of the pressure waves in the head. The pulsewidth dependency of the loudness of microwave hearing is clearly explained by the simulation with realistic head models. The peak pressure of elastic waves in the realistic head models is of the same order as the previously reported values obtained with a homogeneous sphere model. The strength of elastic wave is discussed in consideration of the safety of this phenomenon.
Article
Rectangularly pulsed, 800-MHz microwaves were coupled via waveguide from a 500-W source to the parietal area of the head of normal human observers (Os). Pulse widths from 5 to 150 μS and pulse-repetition rates (PRRs) from 50 to 20,000 pulses per second (pps) were employed. Sine-wave audio-frequency (AF) signals could be presented alternately to or concurrently with microwave pulses (RF signal) under conditions in which O could adjust the amplitude, frequency and phase of the AF signal. By matching timbre and loudness of the perceived RF and AF signals during a succession of psychophysical measures—some while O's head was being immersed in water—the Os yielded the following results: (1) Both loudness and perceptual thresholds of the RF signal were biphasic functions of pulse width and of PRR; (2) When pulse widths increased toward 100 μs, some subjects perceived a different sound that was lower in pitch and was referred externally to the head; (3) By appropriate phasing of AF and RF signals after matching for pitch and timbre, loudness of the RF signal could be reduced below the threshold of perception; and (4) Extent of immersion of the head in water was correlated with reduced loudness of the RF signal. Some of the data are interpreted as posing explanatory difficulties for an exclusively ther-moelastic mechanism of RF hearing.
Article
A psychophysical study of the perception of "sound" induced by illumination with pulse-modulated, ultrahigh-frequency electromagnetic energy indicated that perception was primarily dependent upon peak power and secondarily dependent upon pulse width. The average power did not significantly affect perception. Perceived characteristics of pitch and timbre appeared to be functions of modulation.
Article
Auditory signals generated in humans and animals who are irradiated with short rectangular pulses of microwave energy have been studied. Assuming that the effect arises from sound waves generated in the tissues of the head by rapid, thermal expansion caused by microwave absorption, and using a technique described previously, the governing equations are solved for a homogeneous spherical model of the head under constrained-surface conditions. The results indicate that the frequency of the auditory signal is a function of the size and acoustic property of the head only. While the amplitude and frequency of the microwave-induced sound are higher than those predicted by the stress-free boundary condition formulation, they are compatible with the experimental results reported to date.
Article
When a human subject is exposed to pulsed microwave radiation, an audible sound occurs which appears to originate from within or immediately behind the head. Laboratory studies have also indicated that evoked auditory activities may be recorded from cats, chinchillas, and guinea pigs. Using a spherical model of the head, this paper analyzes a process by which microwave energy may cause the observed effect. The problem is formulated in terms of thermoelasticity theory in which the absorbed microwave energy represents the volume heat source which depends on both space and time. The inhomogeneous thermoplastic motion equation is solved for the acoustic wave parameters under stress-free surface conditions using boundary value technique and Duhamel's theorem. Numerical results show that the predicted frequencies of vibration and threshold pressure amplitude agree reasonably well with experimental findings.
Human perception of illumination of pulsed UHF EM energy
  • A H Frey
  • R Messenger
A.H. Frey and R. Messenger, "Human perception of illumination of pulsed UHF EM energy," Science, vol. 181, pp. 356-358, 1973.