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APPENDIX PM2 - FREY'S PAPER
TRANSCRIPTION, Courtesy of MindNet Archives, Mike Coyle
posted at http://www.ritualabuse.net/MCF/
Frey, Allan H., Human Auditory system response to modulated
electromagnetic energy. J. Appl. Physiol. 17(4): 689-692. 1962.
(*) Asterisks indicate unreadable characters in the original copy.
NOTE: In 1962, frequencies were expressed as kiloCYCLES,
megaCYCLES, etc., with abbreviations being kc, mc
--The intent of this paper is to bring a new phenomena to the
attention of physiologists. Using extremely low average power
densities of electromagnetic energy, the perception of sounds was
induced in normal and deaf humans. The effect was induced several
hundred feet from the antenna the instant the transmitter was turned
on, and is a function of carrier frequency and modulation. Attempts
were made to match the sounds induced by electromagnetic energy and
acoustic energy.
The closest match occurred when the acoustic amplifier was driven by
the rf transmitter's modulator. Peak power density is a critical
factor and, with acoustic noise of approximately 80 db, a peak power
density of approximately 275 mw / rf is needed to induce the
perception at carrier frequencies 125 mc and 1,310 mc. The average
power density can be at rf as low as 400 _u_w/cm2. The evidence for
the various positive sites of the electromagnetic energy sensor are
discussed and locations peripheral to the cochlea are ruled out.
Received for publication 29 September 1961.
A significant amount of research has been conducted with the effects
of radio-frequency (rf) energy on organisms (electro- magnetic energy
between 1 kc and ** Gc). Typically, this work has been concerned with
determining damage resulting from body temperature increase. The
average power densities used have been on the order of 0.1-t w/cm2
used over many minutes to several hours.
In contrast, using average power densities measured in microwatts per
square centimeter, we have found that ****r effects which are
transient, can be induced with rf energy. Further, these effects
occur the instant the transmitter is turned on. With appropriate
modulation, the perception of different sounds can be induced in
physically deaf, as well as normal, in human subjects at a distance
of inches up to thousands of feet from the transmitter. With
somewhat different transmission parameters, you can induce the
perception of severe buffeting of the head, without such apparent
vestibular symptoms as dizziness or nausea. Changing transmitter
parameters down, one can induce a "pins-and-needles" sensation.
Experimental work with these phenomena may yield information on
auditory system functioning and, more generally, in the nervous
system function. For example, this energy could possibly be used as
a tool to explore nervous system coding, possibly using Neider and
Neff's procedures (1), and for stimulating the nervous system without
the damage caused by electrodes.
Since most of our data have been obtained of the "rf sound" and only
the visual system has previously been shown to respond to
electromagnetic energy, this paper will be concerned only with the
auditory effects data. As a further restriction, only data from
human subjects will be reported, since only this data can be
discussed meaningfully at the present time. The long series of
studies we performed to ascertain that we were dealing with a
biological significant phenomena (rather than broadcasts from sources
such as loose fillings in the teeth) are summarized in another paper
(2), which also reports on the measuring instruments used in this
work.
The intent of this paper is to bring this new phenomenon to the
attention of physiologists. The data reported are intended to
suggest numerous lines of experimentation and indicate necessary
experimental controls.
Since we are dealing with a significant phenomenon, we decided to
explore the effects of a wide range of transmitter parameters to
build up the body of knowledge which would allow us to generate
hypotheses and determine what experimental controls would be
necessary. Thus, the numbers given are conservative; they should not
be considered precise, since the transmitters were never located in
ideal laboratory environments. Within the limits of our
measurements, the orientation of the subject in the rf field was of
little consequence.
Most of the transmitters used to date in the experimentation have
been pulse modulated with no information placed on the signal. The
rf sound has been described as being a buzz, clicking, hiss, or
knocking, depending on several transmitter parameters, i.e., pulse
width and pulse-repetition rate (PRF). The apparent source of these
sounds is localized by the subjects as being within, or immediately
behind the head. The sound always seems to come from within or
immediately behind the head no matter how the subjects twists or
rotates in the rf field.
Our early experimentation, preformed using transmitters with very
short square pulses and high pulse-repetition rates, seemed to
indicate that we were dealing with harmonics of the PRF. However,
our later work has indicated that this is not the case; rather, the
rf sound appears to be incidental modulation envelope on each pulse,
as shown in Fig 1.
Some difficulty was experienced when the subjects tried to match the
rf sound to ordinary audio. They reported that it was not possible
to satisfactorily match the rf sound to a sine wave or to white
noise. An audio amplifier was connected to a variable bypass filter
and pulsed by the transmitter pulsing mechanism. The subjects, when
allowed to control the filter, reported a fairly satisfactory match.
The subjects were fairly well satisfied with all frequencies below
5-kc audio were eliminated and the high- frequency audio was extended
as much as possible. There was, however, always a demand for more
high-frequency components. Since our tweeter has a rather good
high-frequency response, it is possible that we have shown an
analogue of visual phenomenon in which people see farther into the
ultraviolet range when the lenses is eliminated from the eye. In
other words, this may be a demonstration that the mechanical
transmission system of the ossicles cannot respond to as high a
frequency as the rest of the auditory system. Since the rf bypasses
the ossicle system and the audio given the subject for matching does
not, this may explain the dissatisfaction of our subjects in the
matching.
FIG. 1. Oscilloscope representation of transmitter output over
time (pulse-modulated).
TRANSMITTER ELECTRONIC NOISE
|--(INCIDENTAL MODULATION)
|
\/
:.:.:.: :.:.:.:
| | | |
| | | |
| | | |
--- --------------- -----------
ON OFF ON OFF
FIG. 2. Audiogram of deaf subject (otosclerosis) who had a "normal"
rf sound threshold.
-10|----|----|----|--|--|--|--|--|--|--|--|
| | | | | | | | | | | |
0|----|----|----|--|--|--|--|--|--|--|--| A = RIGHT BONE
| | A | | | | | | | | |
|----|----B----A--|--|--|--|--|--|--|--| B = LEFT BONE
| | | B | A | | | | | | |
LOSS(db) 20|----|----|----B--B--AB-B--B--B--AB-|--| C = LEFT AIR
| | | | | | | A | | | |
|----|----|----|--|--|--|--|--|--|--|--| D = RIGHT AIR
| | | | | | | | | | | C
40|----|----|----|--|--|--|--|--|--|--C--|
| | C C C | | | | | C | |
|----C----|----D--|--C--C--C--|--D--D--D
| | D | D | | D | | | |
60|----D----|----|--|--D--|--|--|--|--|--|
| | | | | | | | | | | |
|----|----|----|--|--|--|--|--|--|--|--|
| | | | | | | | | | | |
80|----|----|----|--|--|--|--|--|--|--|--|
| | | | | | | | | | | |
|----|----|----|--|--|--|--|--|--|--|--|
| | | | | | | | | | | |
100|----|----|----|--|--|--|--|--|--|--|--|
125 250 500 1000 2000 4000 8000
FREQUENCY (cps)
TABLE 1. Transmitter parameters
Trans- Frequency, Wave- Pulse Width, Pulses Sec. Duty Cy.
mitter mc length, cm _u_sec
A 1,310 22.9 6 244 .0015
B 2,982 10.4 1 400 .0004
C 425 70.6 125 27 .0038
D 425 70.6 250 27 .007
E 425 70.6 500 27 .014
F 425 70.6 1000 27 .028
G 425 70.6 2000 27 .056
H 8,900 3.4 2.5 400 .001
FIG. 3. Attenuation of ambient sound with Flent antinoise stopples
(collated from Zwislocki (3) and Von Gierke (4).
|----|---|--|--|-|-|-|||----|---|--|-|||
| | | | | | | ||| | | | |||
|----|---|--|--|-|-|-|||----|---|--|-||| A = FLENTS
| | | | | | | ||| | | | |||
10|----|---|--|--|-|-|-|||----|---|--|-||| B = THEORETICAL LIMIT
| | | | | | | ||| | | | ||| OF ATTENUATION BY
FUNCTION(db) |----|---|--|--|-|-|-|||----|---|--|-||| EAR PROTECTORS
A | | | | | | ||| | | | |||
|----A---|--|--|-|-|-|||----|---|--|-|||
B | A A A | A AAA A| | | |||
|----B---B--|--|-A-|-|||----A---|--|-|||
| | | | B | | ||| | A | | |||
30|----|---|--|--|-|-|-B||----|---A--|-A||
| | | | | | | ||| | | A |A|
|----|---|--|--|-|-|-|||B---|---|--|-||A
| | | | | | | ||| B | | | |||
|----|---|--|--|-|-|-|||----|---|--|-||B
| | | | | | | ||| B | | B||
|----|---|--|--|-|-|-|||----|---|-B|-|||
| | | | | | | ||| | B | | |||
50|----|---|--|--|-|-|-|||----|---|--|-|||
| | | | | | | ||| | | | |||
|----|---|--|--|-|-|-|||----|---|--|-|||
| | | | | | | ||| | | | |||
|----|---|--|--|-|-|-|||----|---|--|-|||
100 1000 10000
FREQUENCY
TABLE 2. Theshold for perception of rf sound (ambient noise level 70-
90 db).
Peak
Avg Peak Peak Magnetic
Power Power Electric Field
Trans- Frequency, Duty Cy. Density, Density Field amp.
mitter mc mw, cm2 mw, cm2 v cm turns, m
A 1,310 .0015 0.4 267 14 4
B 2,982 .0004 2.1 5,250 63 17
C 425 .0038 1.0 263 15 4
D 425 .007 1.9 271 14 4
E 425 .014 3.2 229 13 3
F 425 .028 7.1 254 14 4
FIG. 4. Threshold energy as a function of frequency of electromagnetic
energy (ambient noise level 70-90 db).
10000|---------|-------------|--------------|
|---------|-------------|--------------|
PEAK |---------|-------------|--------------|
POWER |---------|-------------|-------------*|
DENSITY |---------|-------------|------------*-|
(mw/cm2) | | | * |
|---------|-------------|---------*----|
| | | * |
|---------|-------------|------*-------|
| | | * |
| | | * |
| | | * |
1000|---------|-------------*--------------|
|---------|-----------*-|--------------|
|---------|---------*---|--------------|
| | * | |
|---------|-----*-------|--------------|
| * * * * * * * | |
|---------|-------------|--------------|
| | | |
| | | |
| | | |
100|---------|-------------|--------------|
200 1000 2000 3000
FREQUENCY (mc)
FIG. 5. Microwave power distribution in a forehead model neglecting
resonance effects and considering only first reflections
(from Nieset et al. (5), modified).
| REFLECTED ABSORBED
1.5|--- FREQUENCIES FREQUENCIES
| * *
| * * * = 10% OF INCIDENT
CENTIMETERS |Cortical * POWER
|Tissue *
| * @ = 20% OF INCIDENT
1.0|--- * POWER
| *
| * *
|Bone
| * *
|
0.5|--- * @ @ @ *
|Muscle * @ @
|Fat @ @ *
|Skin @ @ @
0|-----------|-----------|-----------|-----------|---
0 100 1000 10000 100000
FREQUENCY (mc)
FIG. 6. Area most sensitive to electromagnetic energy (shaded portion).
* * * * * *
* *
* *
* * :::::: *
* * ::::::::: *
* O * :::::::: *
* * * *
* * *
* * *
*** ** *
* * *
* * * * *
* *
* *
* * * * * * * * *
At one time in our experimentation with deaf subjects there seemed to
be a clear relationship between the ability to hear audio above 5 kc
and the ability to hear rf sounds. If a subject could hear above 5
kc, either by bone or air conduction, then he could hear the rf
sounds. For example, the threshold of the subject whose audio gram
appears in Fig. 2 was the same average power density as our normal
subjects. Recently, however, we have found people with a notch
around 5 kc who do not perceive the rf sounds generated by at least
one of our transmitters.
THRESHOLDS
As shown in Table 1, we have used a fairly wide range of transmitter
parameters. We are currently experimenting with transmitters that
radiate energy at frequencies below 425 mc, and are using different
types of modulation, e.g., pulse-repetition rates as low as 3 and
4/sec.
In the experimentation reported in this section, the ordinary noise
level was 70-90 db (measured with a General Radio Co. model 1551-B
sound level meter.) In order to minimize the rf energy used in the
experimentation, subjects wore Flent antinoise ear stoppers whenever
measurements were made. The ordinary noise attenuation of the Flents
is indicated in Fig. 3. Although the rf sounds can be heard without
the use of Flents, eventhough they have an ambient noise evel of 90
db, it appears that the ambient noise to some extent "masked" the rf
sound.
Table 2 gives the thresholds for the perception of the sounds. It
shows fairly clearly that the critical factor in the perception of
the rf sound is the peak power density, rather than the average power
density. The relatively high value for transmitter B was expected
and will be discussed below. Transmitter G has been omitted from the
table since the 20-mw/cm2 reading for it can be considered only
approximate. The field-strength-measuring instruments used in that
experiment did not read high enough to give an accurate reading. The
energy from transmitter H was not perceived, even when the peak power
density was as high as 25 w/cm2.
When the threshold energy is plotted as a function of the rf energy
(Fig. 4), a curve is obtained which is suggestive of the curve of
penetration of rf energy into the head. Figure 5 shows the
calculated penetration, by frequency of rf energy, into the head. Our
data indicate that the calculated penetration curve may well be
accurate at the higher frequencies but the penetration at the lower
frequencies may be greater than that calculated on this model.
As previously noted, the thresholds were obtained in a high ambient
noise environment. This is an unusual situation as compared to
obtaining thresholds of regular audio sound. One recent
experimentation leads us to believe that, if the ambient noise level
were not so high, these threshold fields strengths would be much
lower. Since one purpose of this paper is to suggest experiments, it
might be appropriate to theories as to what the rf sound threshold
might be if we assumed that the subject is in an anechoic chamber.
It is also assumed that there is no transducer noise.
Given: As a threshold for the rf sound, a peak power density of 275
mw/cm2 determined in an ambient noise environment of 80 db. Earplugs
attenuate the ambient noise 30 db.
If: 1 mw/cm2 is set equal to o db, then 275 mw/cm2 is equal to 24 db.
Then: We can reduce the rf energy 50 db to -26 db as we reduce the
noise level energy from 50 db to o db. We found that -26 db rf
energy is approximately 3 _u_w/cm2.
Thus: If an anechoic room, rf sound could theoretically be induced
by a peak power density of 3 _u_w/cm2 measured in free space. Since
only 10% of this energy is likely to penetrate the skull, the human
auditory system and a table radio may be one order of magnitude apart
in sensitivity to rf energy.
Up to Contents
RF DETECTOR IN AUDITORY SYSTEM
One possibility that seems to have been ruled out in our
experimentation is that of a capacitor-type effect with the tympanic
membrane and oval window acting as plates of a capacitor. It would
seem possible that these membranes, acting as plates of a capacitor,
could be set in motion by rf energy. There are, however, three
points of evidence against this possibility. First, when one rotates
a capacitor in an rf field, a rather marked change occurs in the
capacitor as a function of its orientation in the field. When our
subjects rotate or change the positions of their heads in the field,
the loudness of the rf sound does not change appreciably. Second,
the distance between these membranes is rather small, compared with
the wavelengths used. As a third point, we found that one of our
subjects who has otosclerosis heard the rf sound.
Another possible location for the detecting mechanism is in the
cochlea. We have explored this possibility with nerve-deaf people,
but the results are inconclusive due to factors such as tinnitus. We
are currently exploring this possibility with animal preparations.
The third likely place for the detection mechanism is the brain. Burr
and Mauro (6) presented evidence that indicates that there is an
electrostatic field about neurons. Morrow and Sepiel (7) presented
evidence that indicates the existence of a magnetic field about
neurons. Becker (personal communication) has done some work
indicating that there is longitudinal flow of charged carriers in
neurons. Thus, it is reasonable to suspect that possibly the
electromagnetic field could interact with neuron fields. As yet,
evidence of this possibility is inconclusive. The strongest point
against it is that we have not found visual effects although we have
searched for them. On the other hand, we have obtained other
nonauditory effects and have found that the sensitive area for
detecting rf sounds is a region over the temporal lobe of the brain.
One can shield, with a 2-in.2 piece of fly screen, a portion of the
stippled area shown in Fig. 6 and completely cut off the rf sound.
Another possibility should also be considered. There is no good
reason to assume that there is only one detector site. On the
contrary, the work of Jones et al. (8), in which they placed
electrodes in the ear and electrically stimulated the subject, is
sufficiently relevant to suggest the possibility of more than one
detector site. Also, several sensations have been elicited with
properly modulated electromagnetic energy. It is doubtful that all
of these can be attributed to one detector.
As mentioned earlier, the purpose of this paper is to focus the
attention of physiologists on an unusual area and stimulate
additional work on which interpretations can be based.
Interpretations have been deliberately omitted from this paper since
additional data are needed before a clear picture can emerge. It is
hoped that the additional exploration will also result in an increase
in our knowledge of nervous system functions.
REFERENCES:
Neider, P.C. and W.D. Neff. Science 133: 1010, 1961.
Frey, A.H. Aero Space Med. 32: 1140, 1961.
Zwislocki, J. Noise Control 4:42, 1958.
Von Gierke, H. Noise Control 2:37, 1956.
Nifset, R., Pinneo R. Baus J. Fleming, & R. McAfee. Ann. Rept. USAF
Rome Air Development Command, TR-61-65, 1961.
Burr, H., & J. Seipel, J. Wash Acad. Sci. 21: 455, 1949.
Morrow, R., & J. Seipel. J. Wash. Acad. Sci. 30: 1, 1969.
Jones, R.C., S.S. Stevens, & M.H. Laurie. J. Acoust. Sci. Am. 12:
281, 1940.
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