United States Patent |
4,335,710
|
Williamson
|
June 22, 1982
|
Device for the induction of specific brain wave patterns
Abstract
Brain wave patterns associated with relaxed and meditative states in a
subject are gradually induced without deleterious chemical or neurological
side effects. A white noise generator (11) has the spectral noise density
of its output signal modulated in a manner similar to the brain wave
patterns by a switching transistor (18) within a spectrum modulator (12).
The modulated white noise signal is amplified by output amplifier (13) and
converted to an audio signal by acoustic transducer (14). Ramp generator
(16) gradually increases the voltage received by and resultant output
frequency of voltage controlled oscillator (17) whereby switching
transistor (18) periodically shunts the high frequency components of the
white noise signal to ground.
Inventors:
|
Williamson; John D. (North Canton, OH)
|
Assignee:
|
Omnitronics Research Corporation (Akron, OH)
|
Appl. No.:
|
112537 |
Filed:
|
January 16, 1980 |
Current U.S. Class: |
600/28 |
Intern'l Class: |
A61N 001/34 |
Field of Search: |
128/1 C,1 R
|
References Cited [Referenced By]
U.S. Patent Documents
2466054 | Apr., 1949 | Siebel | 128/1.
|
3160159 | Dec., 1964 | Hoody et al. | 128/1C.
|
3576185 | Apr., 1971 | Schulz et al. | 128/1.
|
3712292 | Jan., 1973 | Zentmeyer, Jr. | 128/1.
|
3753433 | Aug., 1973 | Bakerich et al. | 128/1.
|
3884218 | May., 1975 | Monroe | 128/1.
|
3892957 | Jan., 1975 | Freeman | 128/732.
|
4034741 | Jul., 1977 | Adams et al. | 128/1.
|
Foreign Patent Documents |
1165541 | Oct., 1969 | GB | 128/1.
|
Primary Examiner: Kamm; William E.
Attorney, Agent or Firm: Hamilton, Renner & Kenner
Claims
I claim:
1. A device for the induction of brain wave patterns associated with
relaxed and meditative states in a subject comprising:
means for generating a white noise signal having a uniform spectral noise
density;
means for receiving said white noise signal and modulating its said
spectral noise density in a manner similar to the brain wave patterns
associated with relaxed and meditative states; and
means receiving said modulated noise signal for coupling said modulated
signal to the subject.
2. A device, as set forth in claim 1, wherein the brain wave patterns
associated with relaxed and meditative states occur in a range of
freqencies, said means for modulating the spectral noise density including
means for modulating said white noise signal beginning at a frequency
greater than that of the brain wave patterns.
3. A device, as set forth in claim 2, wherein said means for modulating the
spectral noise density further includes means for gradually reducing the
frequency at which said spectral noise density is modulated.
4. A device, as set forth in claim 3, wherein said means for modulating the
spectral noise density further includes means for terminating all
modulation of said white noise signal upon reaching its lowest frequency
of modulation.
5. A device, as set forth in claim 3 or 4, wherein said means for
modulating the spectral noise density further includes means for reaching
a steady state frequency of modulation at a frequency slightly lower than
the lowest said brain wave pattern frequency.
6. A device, as set forth in claim 5, wherein said means for modulating
said spectral noise density includes switching means for receiving said
white noise signal, providing said modulated noise signal, and
periodically shunting to ground the high frequency components of said
white noise signal.
7. A device, as set forth in claim 6, wherein said means for modulating
said spectral noise density further includes oscillator means for
controlling the instantaneous frequency at which said switching means
periodically shunts to ground said high frequency components of said white
noise signal and generator means for controlling the instantaneous
frequency of said oscillator means.
8. A device, as set forth in claim 7, wherein said generator means
generates an output signal having a variable voltage, which signal is
received by said oscillator means and causes said oscillator means to
generate a modulation signal having a frequency of from approximately 14
to 15 Hz.
9. A device, as set forth in claim 8, wherein said output signal from said
generator means begins operation at its negative most voltage amplitude
and continuously gradually increases to a steady-state value at its
positive most voltage amplitude, said oscillator means beginning operation
at approximately 14 Hz and continuously gradually increasing to a
steady-state value at approximately 5 Hz, whereby said switching means
modulates the high frequency components of said white noise signal at the
instantaneous frequency of said oscillator means.
10. A device, as set forth in claim 9, wherein said means for coupling said
modulated signal to the subject is a headphone transducer for converting
said modulated signal to an audio signal and having pneumatic tubes
adopted to carry said audio signal to the subject in a non-intrusive
manner while minimizing extraneous acoustical background distractions.
11. A device, as set forth in claim 10, wherein said switching means
includes a switching transistor furnishing said modulated signal, and
further including an output amplifier receiving and amplifying said
modulated signal, said headphone transducer receiving said amplified
modulated signal from said output amplifier.
Description
TECHNICAL FIELD
The present invention relates generally to a device for effecting deep
relaxation in a subject. More particular, the present invention relates to
a device for the induction of brain wave patterns associated with relaxed
and meditative states in a human subject, commonly known as a "brain
driver".
BACKGROUND ART
It has long been recognized that most mammals and in particular humans
exhibit distinct recurring electrical frequencies in their brain wave
patterns, each of which is related to separately identifiable
physiological states. Brain waves having dominant frequencies from
approximately 8-13 Hz, inclusive, are known as Alpha frequency brain waves
and are associated with relaxed and meditative states as would occur when
a subject has his eyes closed but is conscious and not thinking.
Techniques and devices which attempt to promote natural relaxation may be
generally classified as passive or active. Passive devices serve merely to
mask out irritating external noises with more pleasant sounds or utilize
random or "white noise" to psychologically distract the subject from
events which inhibit natural relaxation. Active devices seek to
intentionally induce Alpha frequency brain waves in the subject, a
phenomena known as "brain driving". Irrespective of the manner in which
such brain waves are induced, a subject whose brain waves are principally
in the Alpha frequency range will become deeply relaxed and exhibit the
same beneficial reduced muscular tension and lowered anxiety and adrenalin
levels as are associated with a naturally occurring state of relaxation.
Typical of the numerous passive devices are those which vary the output
signal from a "white noise" source and convert the same to an accoustical
signal, resulting in pleasant masking sounds. In one device, the white
noise source output has its amplitude varied by a saw tooth wave form to
produce sounds similar to waves repeatedly breaking in a surf. In another
device, the output signal from a "white noise" source has its spectral
content and amplitude varied in direct response to a subject's
instantaneous dominant brain wave frequency and amplitude, respectively,
producing a feedback signal to be utilized by the subject to recognize his
present physiological state. All passive devices suffer from a fundamental
inadequacy in that they cannot actually induce Alpha frequency brain waves
with its associated relaxed and meditative condition.
Currently only three basic techniques for forcing a subject into a state
exhibiting Alpha frequency brain waves are known to exist. Perhaps the
most widely used is chemical tranquilizers, always subject to potentially
grave known and unknown negative side effects or contraindications. The
other techniques for "brain driving" involve the use of very bright,
quickly flashing lights, direct electrical pulse stimulation of the brain
through skin electrodes, or some combination thereof. In either instance,
the lights or electrical pulses are synchronized to occur at a rate within
the Alpha frequency range, i.e., from about 8 to 14 Hz. However, such
flashing lights are not only irritating but may likely initiate a seizure
in epileptic individuals. Electrical pulses are not only irritating, but
also may produce unknown, deleterious side effects upon other parts of the
brain or other neurological activity. Moreover, these devices attempt to
very abruptly force the subject from an active and possibly highly
emotional state to a highly relaxed and meditative state, thereby greatly
increasing the likelihood of failure.
DISCLOSURE OF INVENTION
It is, therefore, an object of the invention to provide a device for the
induction of brain wave patterns associated with relaxed and meditative
states in a subject in a safe manner without deleterious or irritating
side effects or contraindications.
It is a further object of the invention to provide a device for the
induction of brain wave patterns associated with relaxed and meditative
states in a subject, as above, which gradually induces such state in the
subject.
It is yet a further object of the invention, to provide a device for the
induction of brain wave patterns associated with relaxed and meditative
states in a subject, as above, which utilizes a pleasing sound that is
modulated and programmed in such manner as to induce Alpha frequency brain
wave patterns only in those brain structures where it naturally occurs.
It is still a further object of the invention to provide a device for the
induction of brain wave patterns associated with relaxed and meditative
states in a subject, as above, which ultimately terminates all variations
in modulation of the sound thereby freeing and encouraging the subject's
brain to assume whatever somnolent brain wave patterns occur naturally to
the subject.
It is still a further object of the invention to provide a device for the
induction of brain wave patterns associated with relaxed and meditative
states in a subject, as above, which includes a source of white noise and
a circuit for modulating the spectral noise density of the white noise in
a manner similar to the brain wave patterns associated with relaxed and
meditative states so as to promote the gradual transition to an Alpha
frequency brain wave condition and the continuous maintenance of the
subject in that condition.
These and other objects and advantages of the present invention over
existing prior art forms will become more apparent and fully understood
from the following description in conjunction with the accompanying
drawings.
In general, a device for the induction of brain wave patterns associated
with relaxed and meditative states in a subject comprises a signal
generator for generating a white noise signal having a uniform spectral
noise density, a modulation circuit for receiving and modulating the white
noise signal, and means for receiving the modulated noise signal and
coupling it to the subject. The modulation circuit modulates the white
noise signal in a manner similar to the brain wave patterns associated
with relaxed and meditative states in the subject, thereby actively
gradually inducing such state in the subject.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an exemplary device according to the concept
of the present invention, and depicts the spectral-noise density modulator
schematically.
FIG. 2 is a somewhat schematic representation of the voltage waveforms at
various points in the device shown in FIG. 1, and although the various
waveforms are in approximate time coordination with each other, they are
not necessarily to scale.
PREFERRED EMBODIMENT FOR CARRYING OUT THE INVENTION
FIG. 1 illustrates a device, generally indicated by the numeral 10, for the
reduction of stress in an individual by the induction of brain wave
patterns associated with relaxed and meditative states. Device 10 broadly
includes white noise generator 11, spectrum modulator 12, output amplifier
13, and acoustic transducer 14.
White noise generator 11 may be any conventional noise generator, either of
the random or impulsive type, that has a level frequency spectrum over the
frequency range of interest. One generator found suitable for use herein
included an operational amplifier providing a thermal noise signal and an
amplification stage.
Spectrum modulator 12 includes transistor shunt gate 15, ramp generator 16,
and voltage control oscillator (hereinafter referred to as VCO) 17.
Transistor shunt gate 15 includes a conventional NPN switching transistor
18, a by-pass diode 19, two summing resistors 20 and 21, and two
capacitors 22 and 23. Ramp generator 16 may be any conventional ramp
generator such as an integrator having a period as detailed hereinbelow
and having a maximum voltage compatible with VCO 17 and transistor shunt
gate 15. A switch 26 may be provided for resetting ramp generator 15 to
its zero point, which for an integrator may be its maximum voltage of
negative polarity, referred to for convenient reference as -V.
VCO 17 may be any of the multitude of well-known astable multivibrators
whose output frequency is a function of the voltage of its input signal.
The frequency range of the output signal from VCO 17 should be slightly
greater than the frequency range of alpha brain wave patterns and
preferably should vary linearly from it highest output frequency when ramp
generator 16 is at its maximum voltage of negative polarity (-V) to its
lowest output frequency when ramp generator 16 is at its maximum voltage
of positive polarity (+V). Where the Alpha brain wave frequency range is
taken to be from approximately 8 to 13 Hz, inclusive, it is adequate to
provide a VCO 17 output signal frequency range from approximately 5 to 14
Hz, inclusive.
Acoustic transducer 14 may be any conventional device for converting the
electrical output signal from transistor shunt gate 15 to an audio signal.
In order to increase the likelihood of relaxation in the subject, it is,
however, highly desirable to provide the least intrusive coupling between
the transducer and the subject while minimizing acoustical background
distractions. Therefore, it has been found preferable to utilize a
conventional headphone transducer having pneumatic tubes 24, 25 adopted to
carry the audio signal to each ear of the subject without applying
noticeable pressure to the subject's head.
The interconnection of the various elements described above is
straightforward. The collector of switching transistor 18 is connected
through capacitors 23 and 22, to noise generator 11 and, through capacitor
23 to output amplifier 13, so that both may receive the output signal from
noise generator 11. The output signal from ramp generator 16 is received
by both VCO 17, and, through resistor 20, the base of switching transistor
18. The output signal from VCO 17 is also received, through resistor 21,
by the base of switching transistor 18. The anode of diode 19 is connected
to the base of switching transistor 18, and has its cathode connected to
ground along with the emitter of switching transistor 18. The output
signal from output amplifier 13 is received by acoustic transducer 14.
To better visualize the operation of device 10, five output signal
waveforms emanating from the various elements noted below have been
illustrated in FIG. 2. Denoted A through D, inclusive, it should be
reiterated at this point that these waveforms are coordinated in time, but
not necessarily in amplitude. These waveforms respectively represent the
output signals from noise generator 11, ramp generator 16, VCO 17, and
transistor shunt gate 15.
Noise generator 11 generates a "white noise" output signal A having a
"uniform" spectral noise density. In other words, this means that the
ratio of the noise output from noise generator 11 within a specific
frequency interval to the frequency interval itself is a constant. As
shall become more evident hereinafter, it is of no moment to the present
invention precisely what this ratio happens to be, it is significant only
that it remains constant.
Spectrum modulator 12 receives white noise signal A from noise generator 11
and modulates its spectral noise density in a manner similar to the brain
wave patterns associated with relaxed and meditative states. More
particularly, spectrum modulator 12 modulates white noise signal A with a
variable frequency in the range of frequencies of Alpha brain wave
patterns. It has been found to be most effective in inducing a relaxed and
meditative state in a subject to begin modulating white noise signal A at
a frequency slightly greater than the frequency associated with the Alpha
brain wave pattern occurring when the subject is most active, and
gradually over a period (T) of minutes reducing the modulation frequency
to a frequency slightly less than the frequency associated with the Alpha
brain wave pattern occurring when the subject is least active. Upon
reaching this lowest modulation frequency, modulation of white noise
signal A is terminated, permitting the subject's natural brain wave
patterns to become dominant.
A typical operating cycle would begin by the closing of switch 26,
resetting ramp generator output signal B to its "zero" voltage -V volts,
and forcing VCO output signal C to its highest frequency of 14 Hz. VCO
output signal C is mixed with ramp generator output signal B and received
by the base of switching transistor 18, causing switching transistor 18 to
alternate at the instantaneous frequency of VCO 17 (then 14 Hz) between
saturation and cutoff operational states. Diode 19 sets the maximum
base-emitter voltage for switching transistor 18.
When operating in a saturated state, switching transistor 18 shunts to
ground the higher frequency components of white noise signal A. When
operating in a cutoff state, switching transistor 18 permits the full
frequency spectrum of white noise signal A to be received by output
amplifier 13. The resultant output from spectrum modulator 12 is output
signal D shown in FIG. 2.
As time proceeds, the voltage of ramp generator output signal B increases,
proportionally decreasing the frequency of VCO output signal C and the
modulation frequency of white noise signal A. When the maximum possible
positive voltage (+V) of ramp generator output signal B is reached, the
frequency of VCO output signal C remains at a constant 5 Hz, and switching
transistor 18 remains in a saturated state, causing all modulation of
white noise signal A to terminate, leaving only the low frequency
components of white noise signal A to be received by output amplifier 13.
Output amplifier 13 receives transistor shunt gate 15 output signal D and
amplifies it to a level compatible with acoustical transducer 14, which
converts the signal to an audio format suitable for direct listening by
the subject. Output amplifier 13 only need be furnished where further
amplification is required.
Several modifications to the depicted embodiment may be noted. Perhaps most
significant is the fact that other spectrum modulation patterns could be
employed herein, although the illustrated continuously decreasing spectral
density modulation is highly advantageous in inducing a relaxed and
meditative condition in a subject. For example, rather than ramp generator
16 generating a continuously increasing voltage signal, continuously
decreasing the frequency of VCO 17, it would be possible to provide
periods of constant voltage output alternated with periods of changing
voltage output, resulting in differing patterns of spectral modulation. An
essentially unlimited number of possible combinations may be effected by
simple adjustment of the generator 16 output signal waveform.
It should also be appreciated that the particular transistor shunt gate 15
shown herewith is merely exemplary of numerous equally suitable circuits
for switching the noise generator output signal A. Transistor shunt gate
15 permits modulation of the higher frequencies contained in the source
signal at rates which corrolates to natural Alpha brain wave pattern
frequencies and, in this manner modifies the spectral noise density of the
source signal.
Inasmuch as the present invention is subject to many variations,
modifications and changes in detail, a number of which have been expressly
stated herein, it is intended that all matter described throughout this
entire specification or shown in the accompanying drawings be interpreted
as illustrative and not in a limiting sense. It should thus be evident
that a device constructed according to the concept of the present
invention, and equivalent thereto, will accomplish the objects of the
present invention and otherwise substantially improve the art of the
induction of specific brain wave patterns in a subject.
* * * * *