These buzzing or clicking sounds however were not meaningful and were not perception of sounds which could otherwise be heard by the receiver. This type of microwave radiation was not representative of any intelligible sound to be perceived. In such radar installations, there was never a sound which was generated which resulted in subsequent generation of microwave signals representative of that sound.
Since the early perception of buzzing and clicking. further research has been conducted into the microwave reaction of the brain. In an article entitled Possible Microwave Mechanisms of the Mammalian Nervous System" by Philip L Stocklin and Brain F. Stocklin, published in the TIT Journal of Life Sciences. Tower International Technomedical Institute. Inc. P.O. Box 4594, Philadelphia. Pa. (1979) there is disclosed a hypothesis that the mammalian brain generates and uses electra magnetic waves in the lower microwave frequency region as an integral part of the functioning of the central and peripheral nervous systems. This analysis is based primarily upon the potential energy of a protein integral in the neural membrane. In an article by W. Bise entitled "Low Power Radio Frequency and Microwave Effects On Human
Electro-encephalogram and Behavior," Physiol. Chemistry Phys. 10. 387 (1978), it is reported that there are significant effects upon the alert human EEG during radiation by low intensity cw microwave electromagnetic energy. Bise observed significant repeatable EEG effects tar a subject during radiation at specific microwave frequencies.
Summary of the Invention
Results at theoretical analysis of the physics ot brain tissue and the brain/skull cavity, combined with experimentally-determined electromagnetic properties at mammalian brain tissue, indicate the physical necessity for the existence of electromagnetic standing waves. called modes in the living mammalian brain. The made characteristics rnay be determined by two geometric properties at the brain: these are the cephalic index at the brain (its shape in prolate spheroidal coordinates) and the semifocal distance of the brain (a measure of its size). It was concluded that estimation ot brain cephalic index and semifocal distance using external skull measurements on subjects permits estimation of the subjects characteristic mode frequencies, which in turn will permit a mode by mode treatment at the data to simulate hearing.
This invention provides for sound perception by individuals who have impaired hearing resulting tram ear damage, auditory nerve damage, and damage to the auditory cortex. This invention provides for simulation of microwave radiation which is normally produced by the auditory cortex. The simulated brain waves are introduced into the region at the auditory cortex and provide for perceived sounds on the part at the subject.
Brief Description Of The Drawings
FIG. 1 shows the acoustic filter bank and mode control matrix portions of the hearing device at this invention.
FIG. 2 shows the microwave generation and antenna portion of the hearing device of this invention.
FIG. 3 shows a typical voltage divider network which may be used to provide mode partition.
FIG. 4 shows another voltage divider device which may be used to provide mode partition.
FIG. 5 shows a voltage divider to be used as a mode partition wherein each of the resistors is variable in order to provide adjustment of the voltage outputs.
FIG. 6 shows a modified hearing device which includes adjustable mode partitioning, and which is used to provide initial calibration of the hearing device.
FIG. 7 shows a group of variable oscillators and variable gain controls which are used to determine hearing characteristics of a particular subject.
FIG. 8 shows a top view of a human skull showing the lateral dimension.
FIG. 9 shows the relationship of the prolate spherical coordinate system to the cartesian system.
FIG. 10 shows a side view of a skull showing the medial plane of the head. section A-A.
FIG. 11 shows a plot of the transverse electric field amplitude versus primary mode number M.
FIG. 12 shows a left side view of the brain and auditory cortex.
FIG. 13 shows the total modal field versus angle for source location.
Detailed Description of the Preferred Embodiment
This invention is based upon observations at the physical mechanism the mammalian brain uses to perceive acoustic vibrations. This observation is based in part upon neuro anatomical and other experimental evidence which relates to microwave brain stimulation and the perception of sounds. It is has been observed that monochromatic acoustic stimuli (acoustic tones, or single tones) of different frequencies uniquely stimulate different regions at the cochlea.
It has also been observed that there is a corresponding one to one relationship between the frequency of a monochromatic acoustic stimulus and the region of the auditory cortex neurally stimulated by the cochlcar nerve under the physiologically normal conditions tonotopicity).
It has been observed that for an acoustic tone of a frequency which is at the lower end at the entire acoustical range perceivable by a person, that thin lateral region ("Line") parallel to the medial axis of the brain and toward the infenor portion of the primary auditory cortex is stimulated. For an acoustic tone whose frequency is toward the high end of the entire perceivable acoustic range, a thin lateral region parallel to the medial axis and toward the superior portion at the primary auditory cortex is stimulated. Neural stimulation results in the generation at a broad band of microwave photons by the change in rotational energy state of protons integral to the neuron membrane of the auditory cortex.
The physical size and shape of the brain/skull cavity, together with the (semiconductor) properties (conductivity and dielectric constant) of the brain tissue provide an electromagnetic resonant cavity. Specific single frequencies are constructively reinforced so that a number of standing electromagnetic waves, each at its own single electromagnetic frequency in the microwave frequency region. are generated in the brain. Each such standing electromagnetic wave is called a characteristic mode of the brain/skull cavity. Analysis in terms of prolate spheroidal wave functions indicates that transverse electric field components of these modes have maxima in the region of the auditory cortex.
This analysis further shows that transverse electric field possess a variation of amplitude with angle in the angular plane (along the vertical dimension of the auditory cortex) and that is dependent only upon the primary mode number. The auditory cortex in the normally functioning mammalian brain is a source of microwave modes. The auditory cortex generates these modes in accordance with the neural stimulation of the auditory cortex by the cochlear nerve. Mode weighting for any one acoustic tone stimulus is given by the amplitude of each mode along the line region of the auditory cortex which is neurally stimulated by that acoustic tone stimulus.
A listing of mode weighting versus frequency of acoustic stimulus is called the mode matrix. In this invention, the functions of the ear, the cochlear nerve, and the auditory cortex are simulated. Microwaves simulating the mode matrix are inserted directly into the region of the auditory cortex. By this insertion of simulated microwave modes, the normal operation of the entire natural hearing mechanism is simulated.
Referring now to FIG. 1 and FIG. 2 there is shown an apparatus which provides for induced perception of sound into a mammalian brain. This bearing device includes a microphone 10 which receives sounds, an acoustic filter bank 12 which separates the signals from the microphone into component frequencies, and a mode control matrix 14 which generates the mode signals which are used to control the intensity of microwave radiations which are injected into the skull cavity in the region of the auditory cortex. The acoustic filter bank 12 consists of a bank of acoustic filters Fl through Fk which span the audible acoustic spectrum. These filters may be built from standard resistance, inductance, and capacitance components in accordance with well established practice.
In the preferred embodiment there are 24 filters which 63 correspond to the observed critical bandwidths of the human ear. In this preferred embodiment a typical, list at filter parameters is given by Table I below:
The rectifier outputs one through K are feed to K mode partition devices. The mode partitioning devices each have N outputs wherein N is the number of microwave oscillators used to generate the microwave radiation. The outputs 1 through N of each mode partition device is applied respectively to the inputs of each gain controlled amplifier of the microwave radiation generator. The function of the mode control matrix 14 is the control of the microwave amplifiers in the microwave amplifier bank 18. In the preferred embodiment thus will be 24 outputs and 24 microwave frequency oscillators.
Connected to each microwave amplifier gain control line is a mode simulation device 16 which receives weighted mode signals from the mode partition devices 14. Each mode simulation device consists of one through k lines and diodes 17 which are each connected to summing junction 19. The diodes 17 provide for isolation from one mode partition device to the next. The diodes 17 prevent signals from one mode partition device from returning to the other mode partition devices which are also connected to the same summing junction of the mode summation device 16. The diodes also serve a second function which is the rectification of the signals received from the acoustic filter bank by way of the mode partition devices. In this way each mode partition device output is rectified to produce a varying DC voltage with major frequency components of the order of 15 milliseconds or less. The voltage at the summation junction 19 is thus a slowly varying DC voltage.
The example mode partition devices are shown in greater detail in FIG. 3, FIG. 4, and FIG. 5. The mode partition devices are merely resistance networks which produce 1 through N output voltages which are predetermined divisions of the input original from the acoustic filter associated with the mode partition device.
FIG. 3 shows a mode partitioning device wherein several outputs are associated with each series resistor 30.
In the embodiment depicted in FIG. 4 there is an output associated with each series resistor only, and thus there are N series resistors, or the same number of series resistors as there are outputs. The values of the resistors in the mode partition resistor network are determined in accordance with the magnitudes of the frequency component from the acoustic filter bank 12 which is required at the summation point 19 or the gain control line for amplifiers 20. The microwave amplifier bank 18 Consists of: plurality of microwave oscillators 1 through N each of which is connected to an amplifier
20. Since the amplifiers 20 are gain controlled by the signals at summation junction 19. the magnitude of the microwave output is controlled by the mode control matrix outputs Fl through F. In the preferred embodiment there are 24 amplifiers. The leads from the microwave oscillators I through N to the amplifiers 20 are shielded to prevent cross talk from one oscillator to the next, and to prevent stray signals from reaching the user of the hearing device. The output impedance of amplifiers 20 should be 1000 ohms and this is indicated by resistor 21. The outputs of amplifiers 20 are all connected to a summing junction 22. The summing junction 22 is connected to a summing impedance 23 which is approximately 50 ohms. The relatively high amplifier output impedance 21 as compared to the relatively low summing impedance 23 provides minimization of cross talk between the amplifiers. Since the amplitude of the microwave signal needed at the antenna 24 is relatively small, there is no need to match the antenna and summing junction impedances to the amplifier 20 output impedances. Efficiency of the amplifiers 20 is not critical. Level control of the signal at antenna 24 is controlled by pick off 25 which is connected to the summing impedance 23.
In this manner the signal at antenna 24 can be varied from 0 (ground) to a value which is acceptable to the individual. The antenna 24 is placed next to the subject's head and in the region of the subjects auditory cortex 26. By placement of the antenna 24 in the region of the auditory cortex 26. the microwave field which is generated simulates the microwave field which would be generated if the acoustic sounds were perceived with normal hearing and the auditory cortex was functioning normally.
In FIG. 2 A there is shown a second embodiment of the microwave radiation and generator portion of the hearing device. In this embodiment a broad band microwave source 50 generates microwave signals which are feed to filters 52 through 58 which select from the broad band radiation particular frequencies to be transmitted to the person. As in FIG. 2 the amplifiers 20 receive signals on lines 19 from the mode control matrix. The signals on lines 19 provide the gain control for amplifiers 20.
In FIG. 6 there is shown a modified microwave hearing generator 60 which includes a mode partition resistor divider network as depicted in FIG. 5. Each of the mode partition voltage divider networks in this embodi ment are individually adjustable for all ot the resistances in the resistance network.
FIG. 5 depicts a voltage division system wherein adjustment of the voltage partition resistors is provided for.
In FIG. 6, the sound source 62 generates audible sounds which are received by the microphone of the microwave hearing generator 60. In accordance with the operation described with respect to FIG'S 1 and 2. microwave signals are generated at the antenna 10 in accordance with the redistribution provided by the mode control matrix as set forth in FIG. 5. The sound source 62 also produces a signal on line 6-4 which is received by a head phone 66. The apparatus depicted in FIG 6 is used to calibrate or fit a microwave hearing generator to a particular individual. Once the hearing generater is adjuasted to the particular individual by adjustment of the variable resistors in the adjustable mode partition portion of the hearing generator.
A second generator may be built using fixed value resistors in accordance with the adjusted values achieved in fitting the device to the particular subject The sound produced by headphone 66 should he the same as a sound from the sound source 62 which is received by the microphone 10 in the microwave hearing generator 60. In this way, the subject can make comparisons between the perceived sound from the hearing generator 60. and the sound which is heard from headphone 66. Sound source 62 also produces a signal on 68 which is feed in cue light 69. Cua light 69 comes on whenever a sound is emitted from sound source 62 to the microwave generator 60.
(A piece of text omitted here--illegible)
In Fig. 7 there is shown a modified microwave generator which may be used to determine a subject's microwave mode frequencies. In this device the acoustic filter bank and the mode control matrix have been removed and replaced by voltage level signals generated by potentiometers 70. Also included ar a plurality of variable frequency oscillators 72 which feed microwave amplifiers 74 which are gain controlled from the signal generated by potentiometers 70 and pick off arm 76.?
This modified microwave hearing generator is used to provide signals using one oscillator at a timi. When an oscillator is turned on. the frequency is varried about the estimated value until a maximum acoustic perception by the subject is perceived. This perception however may consist of a buzzing or hissing sound tat rather than a tone because only one microwave frequencies being received. The first test of perception is to determine the subject's lowest modal frequency for audibility. (M= 1). Once this modal frequency is obtained. The process is repeated for several higher modal frequencies and continued until no maximum acoustic perception occurs.
«- Previous | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | View All | Next -»