Apparatus for use by physicians in acupuncture research

Abstract

Apparatus for use in research into acupuncture anesthesia or analgesia and other acupuncture therapy having means to vary the amplitude, frequency and amperage of electrical impulses applied to pairs of acupuncture needles. A frequency variable relaxation oscillator is utilized to trigger at selectively variable intervals of time a monostable multivibrator which determines the output pulse interval. The multivibrator output pulse train is shaped and amplified before being applied to a separate pulse generator and isolation transformer for each output channel to generate the output waveform. Each channel includes an attenuator which is used to vary the amplitude of the output waveform and thereby vary the output current. Each channel is also protected against power surges thereby limiting the maximum output current. The output waveform which has been found to produce the most effective results is a steep positive-going pulse having a generally rounded crown followed in 0.5 millisecond by a steep negative-going pulse of approximately the same magnitude of negative voltage and abruptly decaying exponentially to zero in about the same time interval.

Description

BACKGROUND OF THE INVENTION

The ancient Chinese art of acupuncture, sometimes referred to as a method or means for treating physical and mental illnesses and the alleviating of pain, was based upon a theory reaching back in history to as long ago as approximately 2500 B.C. Throughout the centuries it was believed that there were some 12 pairs of "meridians" plus two trunk "meridians" which connected all of the internal organs of the body with different points on the surface of the body.

It has only been in more recent years, when the medical sciences of the Western World and in the People's Republic of China have become aware of each other's existence, that the ancient concept of these "meridians" has been abandoned and a more scientific analysis has been reached in an effort to understand the "mechanism" or physiological and/or neurological effect of acupuncture. Strangely, there seems to be a surprising coincidence between the locations of the so-called "meridian points" and the peripheral nerves as revealed by modern study.

In ancient times the technique of acupuncture was used for the alleviation of pain, in a sense producing an analgesic effect limited to only pain response, without incapacitation of the other functions of the body. This may be explained by the fact that the acupuncture needles merely were inserted into the body. Sometimes as many as 8 needles were inserted into a patient in order to produce the desired pain relief. It was later discovered that by manual twirling or arcuate oscillation of the needles around their longitudinal axes, as by the fingers of a trained acupuncture anethesiologist, the effect of the treatment could be greatly enhanced.

In itself, however, the "twirling" technique presented a further problem in that it became very tiring to the hand of the manipulator and it required a skilled manipulator in order to obviate the possibility that the needle points might be dislodged from their proper location, either being inserted more deeply or withdrawn somewhat during the twirling of the needles. Furthermore, of course, because even a skilled person has only two hands, only two needles could be simultaneously twirled by a single operator. While a single acupuncture analgesic treatment might last only 20 or 30 minutes, if an operator were to continue to treat patients throughout the day, the total activity of his hands would induce considerable fatigue. A further problem resulted from the fact that it was almost impossible for the operator to maintain a desired frequency of twirling thus to produce a desired or effective frequency of the impulses resulting from the twirling of the needles.

Much more recently the Chinese have suggested that the manual twirling of the needles be replaced by the application of cyclical electrical stimuli to the needles. The Chinese utilized a nine-volt stimulating machine provided with circuitry to produce an alternating current of 300 cycles per second. Each of the two leads from the machine was attached to one of a pair of needles inserted subcutaneously at the locations determined by the attending physician to enhance the pain-blocking effect and, as recently as 1958, the Chinese began to use this technique for surgery in addition to pain alleviation.

In our lengthy study of the literature and history of acupuncture, particularly for the alleviation of pain, we have determined that while the use of cyclical electrical impulses delivered to the inserted acupuncture needles is a most effective way to create the necessary stimulation in order to block pain, much more flexibility is necessary in order to enable skilled physicians to conduct controlled scientific research into the mechanism of acupuncture itself, into the reasons underlying its therapeutic effect and to establish certain criteria which may be utilized by the medical profession at large.

SUMMARY OF THE INVENTION

The present invention relates to an apparatus for use in research into acupuncture anesthesia or analgesia and acupuncture therapy and specifically to circuitry for generating electrical impulses of a form which has been found to produce the most effective results. A unijunction transistor relaxation oscillator having a variable frequency rate from approximately 2 to 150 hertz is utilized to trigger a monostable multivibrator to produce a square wave having a predetermined timing interval, typically 0.5 milliseconds. The square wave is shaped and amplified to provide an input signal to separate pulse generators and isolation transformers for each of three output channels. Each output channel includes protection against power surges and output current limiting devices as well as attenuators for varying the amplitude of the output waveform and thereby the output current.

The output voltage of any channel is applied to a pair of acupuncture needles which are inserted in a portion of the body. Since each output channel is independent of the others, selected portions of the body may be stimulated by electrical impulses differing in strength with the variations in each not effecting operation of the others. Provision is also made for monitoring the output waveforms by use of suitable means, such as an oscilloscope, and monitoring average output current by use of a microammeter.

Accordingly it is the principal object of the invention to provide an apparatus for utilization by physicians in acupuncture research more fully to study the neurophysiological aspects of the technique by providing the physician with means to vary the strength, quantity and rapidity of the electrical inpulse delivered to the acupuncture needles as indicated during the course of treatment.

It is a further object of the instant invention to provide such an apparatus in which the wave form delivered to the needles is closely controlled to that which we have learned produces the more effective results.

And it is yet another object of the instant invention to provide such an apparatus having inherent control which precludes the possibility of the so-called "avalanche effect", limiting the output of the machine to a maximum of 50 microamperes, thus to pprotect a patient being treated from the danger of excessive electrical current.

Yet another object of the instant invention is to provide an apparatus with a plurality of output circuits, each of which may be independently controlled and varied as desired by the attending physician in order that a plurality of pairs of acupuncture needles inserted into selected positions in the body may be stimulated by stimuli differing in strength, quantity and frequency, each of the several output circuits being controllable independently of the others and the variations in each not effecting the operationof the others.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the wave form generating circuit of the present invention;

FIG. 2 is a schematic diagram of the circuit represented by the block diagram of FIG. 1;

FIG. 3 is the voltage wave form generated by the multivibrator of FIGS. 1 and 2;

FIG. 4 is the voltage wave form generated by the wave shaper of FIGS. 1 and 2;

FIG. 5 is the voltage wave form generated at the inputs to the pulse generator and isolation transformers of FIGS. 1 and 2;

FIG. 6 is the voltage wave form generated at the inputs to the Darlingtion pair amplifiers included in the pulse generators and isolation transformers of FIGS. 1 and 2;

FIG. 7 is the output voltage wave form available from each channel of present invention; and

FIG. 8 is a front elevation of the control panel of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to better understand the apparatus embodying the instant invention, as it will hereinafter be described in detail, it is believed desirable to explain in brief the theory which we have developed during the course of our research and study and which we believe is the best available explanation of the mechanism of acupuncture, and thus the reasons why we have developed the apparatus to be described.

It appears now to be accepted among students and research scientists into the field of acupuuncture that, in general, the peripheral nervous system comprises what may be called both large and small fibers, i.e., each individual nerve is comprised of both types of fibers and they are intermingled with each other in the body of the nerve. It has also been discovered that the large fibers do not, in themselves, deliver pain sensations and that the pain sensations delivered to the brain travel in the small fibers of the nerve. We have also discovered that the large fibers of the nerve require a small amount of stimuli and that the stimuli travel in the larger fibers at a higher rate of speed. Conversely, the smaller fibers of the nerve require a greater degree of stimulation and the stimuli travel in the smaller fibers at a lower rate of speed.

Each of the peripheral nerves leads to the substantia gelatinosa of the spinal cord, i.e., the synapse. Our theory is based upon the concept that at the substantia gelatinosa there is located what may be called a "gate". The large non-pain fibers of the nerve are stimulated by the acupuncture treatment to a degree determined by the strength, quantity and frequency of the electrical impulses delivered to the needles and these stimuli reach the "gate" very quickly, thus closing the "gate". The subsequent delivery by the smaller or pain delivering fibers of the pain stimuli to the pain centers of the brain is thus blocked from reaching the brain by the closing of the gate resulting from the stimuli delivered to the gate through the high steep, low stimuli-responsive, larger fibers.

Because of the variation in pain threshold known to exist between patients, resulting from many factors readily understood by neurologists such as attitude, distraction, conditioning, hypnotism (self-induced or not), religious and political convictions, fear, fatigue, illness, etc., no absolute criteria can be established upon which to base treatment of different persons even for the same problem.

The theory so far described explains why pain otherwise delivered to the responsive centers of the brain by the smaller fibers of a peripheral nerve is successfully blocked by proper acupuncture treatment of that nerve to close the gate at the substantia gelatinosa of the spinal cord. It does not explain how acupuncture treatment can be utilized with the needles located in one portion of the body and pain blocked in another portion of the body as, for example, the insertion of needles into the appropriate location in the hand of the patient to block pain otherwise resulting from a tooth extraction.

Our theory, however, is based upon hypothecation of a second or main gate in the neurological system of the body. It is known that the larger fibers of the peripheral nerves not only send branches to the upper segments thereof but they also send branches via the dorsal column to nuclei gracilis and cuneatus where the impulses are relayed to the posterolateral ventral nucleus of the thalamus. Delivery of the stimuli along the larger fibers to the thalamus closes this second or main gate and thus produces analgesia or, anesthesia, if the acupuncture needles are properly inserted into a peripheral nerve.

In the apparatus embodying the invention which has been developed by use in order to test and to prove the theories briefly outlined above, we have provided means whereby more than one pair of needles simultaneously may be inserted into selected positions in the body without requiring the tedious twirling so that a single apparatus may be utilized by a physician for the application of varying stimuli to various selected points or areas of the body as he determines in his research and experimentation. Such research and study indicated that the use of our apparatus appears to be very effective for blocking the sensation of pain, either from that part of the body directly associated with the locations into which the needles are inserted, or even to other parts of the body dramatically remote from the areas of locations into which the needles are inserted.

For further discussion of the "Two-gate Control Theory" reference may be had to the article by Drs. Man and Chen published in "Diseases of the Nervous System", Vol. 33, pp. 730-735, November, 1972, (Physicians Post Graduate Press, Irvington, N.J.).

Referring to FIG. 1, there is shown a block diagram of the present invention in its preferred embodiment. Relaxation oscillator 10, monostable multivibrator 11 and wave shaper 12 produce a train of electrical impulses to pulse generators and isolation transformers 13, 14 and 15 of output channels 1, 2 and 3. Each output channel is connected to a pair of needles adapted to be inserted into selected portions of the body and the amount of applied current is adjusted by attenuators 16, 17 and 18. Each output pulse is comprised of a steep positive-going portion having a generally rounded crown and which decays in approximately 0.5 millisecond as a steep transition from the crown to negative peak of about the same absolute value as to the top of the crown. The steep negative peak decays exponentially in approximately 0.5 millisecond.

As illustrated more specifically in FIG. 1, a suitable direct current power source, typically portable batteries not shown, is utilized to energize relaxation oscillator 10 at input 19. Oscillator 10 is adjustable to generate a train of pulses having a pulse rate variable within predetermined limits. This train of pulses is applied to the trigger input of monostable multivibrator 11 which generates a square wave, that is a wave with a steep rise and fall at a pulse rate equal to the rate of the pulse train from oscillator 10. Multivibrator 11 has a predetermined timing cycle which determines the duration of each square wave. The square wave output of multivibrator 11 is applied to wave shaper 12 which produces a positive-going pulse above a bias voltage which is equal in duration to the square wave.

The pulses from wave shaper 12 are applied to pulse generators and isolation transformers 13, 14 and 15 where they are utilized to produce output pulses which are applied to outputs 21, 22 and 23 through attenuators 16, 17 and 18. The steep leading edge of the waveform issued by wave shaper 12 defines the instant the output pulse develops its steep leading edge, t.sub.1 in FIGS. 4-7 and the steep negative going transition defines the instant t.sub.2 in which the output pulse initiates its negative going transient. Each channel is independent from the others and each output current may be adjusted separately. Pulse generators and isolation transformers 13, 14 and 15 also include current limiting devices to protect against power surges.

FIG. 2 is a schematic diagram of the waveform generating circuit represented by the block diagram of FIG. 1. Direct current power source 24, typically a nine volt mercury battery, is connected to input 19 through "ON-OFF" switch 25. When switch 25 is closed current will flow through pilot light 26 to provide a visual indication that the circuit is energized. Current also will flow through zener diode 27, resistor 28 and battery charge indicator 29. As power source 24 discharges, the battery voltage will fall until a critical level is reached at which the circuit can no longer deliver full output power. When a nine volt mercury battery is utilized this critical level is approximately six volts. Between nine volts and six volts current will flow through zener diode 27 and resistor 28 to provide a visual indication from battery charge indicator 29. When the power source voltage falls below six volts, zener diode 27 will block all but a very small reverse current and battery charge indicator 29 will indicate that replacement batteries are required.

Variable resistor 31, capacitor 32, unijunction transistor 33 and resistor 34 form relaxation oscillator 10 of FIG. 1. Capacitor 32 is charged through variable resistor 31 to the peak emitter voltage of transistor 33. During this charging period only a small emitter leakage current will flow and the transistor is in its cut-off region so that effectively there is no current flow through resistor 34 and the base of transistor 35 is at ground. When the capacitor voltage reaches the peak voltage the emitter will become forward biased and the emitter current will flow. At the peak voltage, transistor 33 enters a negative resistance region in which the emitter to base one (connected to resistor 34) resistance decreases so that as the emitter current increases the emitter voltage decreases. Therefore, capacitor 32 discharges through transistor 33 and resistor 34 to the valley voltage at which the transistor enters the saturation region where the emitter to base one resistance becomes positive. The decrease in resistance between the emitter and base one will increase the current flow through transistor 33 and resistor 34 until the voltage drop across resistor 34 is high enough to reverse bias the emitter and return transistor 33 to the cut-off region. Capacitor 32 will again charge to the peak voltage and the cycle will be repeated. During the discharge of capacitor 32, current flow through resistor 34 will produce a positive-going pulse at the base of transistor 35. Capacitor 36 is connected across relaxation oscillator 10 to filter out any voltage variations created by the turning on and off of unijunction transistor 33 as the output pulses are generated.

Variable resistor 31 may be adjusted to change the charging rate of capacitor 32 and thereby obtain various pulse rates, typically two to one hundred fifty hertz, for the pulse train applied to transistor 35. During the absence of a pulse at its base, transistor 35 is in the cut-off region so that no current is flowing in resistor 37 and the input of monostable multivibrator 11, which is connected to the collector of transistor 35, is at the power source voltage. When relaxation oscillator 10 generates a pulse, transistor 35 is placed in a conducting state and the input to multivibrator 11 is drawn toward ground. After the pulse at its base, transistor 35 returns to cut-off thereby generating a square wave at the input to multivibrator 11.

Multivibrator 11 includes timer 38, timing resistor 39 and capacitor 41 and control voltage capacitor 42. Timer 38 has an internal flip-flop which places a short circuit across capacitor 41 at discharge input 38-7 and ground 38-1, to drive output 38-3 low. When transistor 35 turns on and the voltages at trigger input 38-2 begins to decrease, the flip-flop releases the short circuit across capacitor 41 and drives the voltage at output 38-3 high. The voltage across capacitor 41 increases exponentially with a time constant equal to the product of the capacitance of capacitor 41 and the resistance of charging resistor 39. When this voltage reaches two-thirds of the power source voltage applied at input 38-8 it is sensed at threshold input 38-6 and flip-flop resets to short circuit capacitor 41 which discharges through discharge input 38-7. The voltage at output 38-3 then goes low forming a square wave. Timer 38 triggers when the voltage at trigger input 38-2 falls to one-third of the power source voltage. Since the charge rate and the threshold voltage are both proportional to the power source voltage, the timing interval is independent of the power source voltage and is equal to 1.1 times the time constant for charging capacitor 41. FIG. 3 shows the square wave output voltage at output 38-3 with the interval between t.sub.1 and t.sub.2 being the timing interval, typically 0.5 millisecond which determines the interval between the positive and negative going transients of the output pulses. Timer 38 may be reset at reset input 38-4 during the charging of capacitor 41. Therefore, input 38-4 is connected to the power source to prevent any possibility of false triggering. Control voltage input 38-5 may receive an amplitude modulated signal which will vary the output pulse width. Since pulse width modulation is not required in the present invention, capacitor 42 is connected to input 38-5 to hold the control voltage at two-thirds of the power source voltage.

The square wave pulse train from timer output 38-3, as shown in FIG. 3, is applied to wave shaper 12 which comprises capacitor 43 and resistors 44 and 45. Resistors 44 and 45 act as a voltage divider for the power source voltage biasing the base of transistor 46 at V.sub.B, typically about 0.8 volts, as shown in FIG. 4. When the leading edge of the square wave from multivibrator 11 appears at capacitor 43 at time t.sub.1, capacitor 43 is storing a charge created by the low output voltage from output 38-3 of timer 38 and the bias voltage across resistor 45. Since the voltage across a capacitor cannot change instantaneously, the voltage across resistor 45 will be increased by the amount of change in the output voltage from output 38--3 of timer 38 at time t.sub.1, as shown in FIG. 4. Then as capacitor 43 charges toward the higher voltage level of the square wave, the voltage across resistor 45 will decay exponentially toward V.sub.B. However, the time constant for the charging of capacitor 43 is much larger than the time interval of the square wave and therefore, there will be very little decrease in the voltage across resistor 45 by time t.sub.2. At t.sub.2 the square wave returns to the low voltage level and since the voltage across capacitor 43 cannot change instantaneously, the voltage across resistor 45 will be decreased by the amount of change in the output voltage from output 38-3 of timer 38. Then, as capacitor 43 discharges to this lower voltage level, the voltage across resistor 45 will increase exponentially to V.sub.B.

The voltage drop V.sub.B across resistor 45 keeps transistor 46 in its conducting state so that there is current flow through and a voltage drop V.sub.C, typically about 2.8 volts across resistor 47. When the leading edge of the waveform from wave shaper 12 is applied to the base of transistor 46 at time t.sub.1, transistor 46 will be driven into saturation until the time t.sub.2 when the trailing edge the waveform from wave shaper 12 occurs, as shown in FIG. 5. Therefore, transistor 46 functions as a current amplifier for the output of wave shaper 12 and applies a square wave to the inputs of blocking oscillators and isolation transformers 13, 14 and 15.

The voltage across resistor 47, typically about 6.3 volts maximum, is applied to capacitor 48. At time t.sub.1, the leading edge of the square wave of FIG. 5 will produce a similar voltage increase at the base of transistor 49 since the voltage across capacitor 48 cannot change instantaneously. As capacitor 48 charges to this applied voltage, the voltage at the base of transistor 49 will decay exponentially toward round. However, the charging time constant for capacitor 48 is much greater than the time interval t.sub.2 - t.sub.1 and therefore, the voltage at the base of transistor 49 will decrease by the amount of decrease in the voltage across resistor 47 at time t.sub.2 to produce the waveform shown in FIG. 6. Diode 51 has its cathode connected to ground and its anode connected between capacitor 48 and transistor 49. Diode 51 provides a path to ground for any negative portion of the waveform at the base of transistor 49 while blocking the positive portion of the waveform unless it exceeds the reverse breakdown voltage. Therefore, diode 51 is a safety device which protects against a sudden power surge in the circuit which could be reflected in the outputs.

Transistors 49 and 52 have their collectors connected together and the emitter of transistor 49 is connected to the base of transistor 52 to form a Darlington pair amplifier. This type of amplifier has the advantages of high current gain and high input impedance. High current gain is required to provide a fifty microamp maximum output current since the output voltage is stepped-up from the voltage of the power source. The high input impedance contributes to the long time constant for the charging of capacitor 48. The collectors of transistors 49 and 52 are connected to the primary winding of transformer 53 which in turn is connected to power source 24. Before time t.sub.1, the base of transistor 49 will be at ground placing transistors 49 and 52 in cut-off and preventing current flow in the primary winding of transformer 53. At time t.sub.1, the square wave shown in FIG. 6 will turn on transistors 49 and 52. Since the current flow through an inductor cannot change instantaneously, the power source voltage will appear across the primary winding and will be steppedup by the secondary winding of transformer 53, as shown in FIG. 7, to approximately sixty volts above the reference level V.sub.REF. This output voltage will decay exponentially with a time constant which is approximately one fourth of time interval t.sub.1 to t.sub.2 as the current flow increases while a magnetic field is established until the only voltage drop across the primary winding is due to its internal resistance. At time t.sub.2 the voltage at the base of transistor 49 decreases to turn off transistors 49 and 52 and prevent further current flow through the primary winding of transformer 53. Now the magnetic field established in the primary winding by the current flow will collapse, inducing a negative voltage in the secondary winding as shown in FIG. 7. The collapse of the field will occur exponentially to return the output voltage to zero at time t.sub.3 for a total time interval between t.sub.1 and t.sub.3 of approximately one millisecond. The induced negative voltage of the field collapse passes through the emitter-collector circuit of transistor 46 and resistor 47 producing the decay curve following t.sub.2 in FIG. 2 which is also reflected in the decay at that time at the base of transistor 49 as shown in FIG. 6.

A secondary winding of transformer 53 is connected in parallel with resistor 54. The voltage induced in the secondary winding of transformer 53 produces current flow through resistor 54 and through a parallel path which includes output jack 55 and resistor 56, which is attenuator 16 of FIG. 1. Terminals 57 and 58 of jack 55 are internally electrically connected by spring contact fingers to provide a current path from the secondary winding of transformer 53, through the contact fingers, through resistor 56 and through a portion of resistor 54 between an adjustable tap attached to terminal 59 and the secondary winding. If plug 61 is inserted into jack 55, the contact fingers connected to terminals 57 and 58 will be separated to interrupt the current path through resistor 56. The contact finger connected to terminal 57 will be in electrical contact with terminal 59 of jack 55. If terminals 62 and 63 are then connected to a pair of needles, 64 and 65, by suitable means such as wire leads and "alligator" clips while the needles are inserted into a portion of the human body, a current flow path will be established. The tap point on resistor 54 may be adjusted to vary the amplitude of the waveform applied to needles 64 and 65 thereby controlling the amount of current which will flow between them. The value of resistor 54 permits adjustment from near zero current to a maximum of 50 microamps. Monitor jack 66 is connected between terminals 57 and 59 of output jack 55 at terminals 67 and 68 rspectively. When plug 69 is inserted into jack 66, contact fingers will electrically connect terminals 67 to 71 and 68 to 72 respectively to permit the output voltage applied to needles 64 and 65 to be monitored by suitable high impedance means such as oscilloscope 73.

The voltage waveform across resistor 47, as shown in FIG. 5, is also applied to pulse generator and isolation transformer 14 of channel 2. Capacitor 74 produces the waveform shown in FIG. 6 at the base of transistor 75 which is connected to transistor 76 as a Darlington pair amplifier. Diode 77 protects against sudden power surges from the pulse train generating circuitry. Transformer 78 steps-up the voltage and produces the waveform shown in FIG. 7 across resistor 79 which is attenuator 17 of FIG. 1. When plug 81 is inserted into jack 82 the contact fingers connected to terminals 83 and 84 will be separated to interrupt the current path through resistor 85. The contact fingers connected to terminals 86 and 87 of plug 81 will be electrically connected to contact fingers connected to terminals 83 and 88 of jack 82 to supply the output voltage to needles 89 and 91. Terminals 92 and 93 of monitor jack 94 are connected to terminals 83 and 88 of output jack 82 respectively. When plug 95 is inserted into jack 94 contact fingers connected to terminals 96 and 97 will be electrically connected to contact finger connected to terminals 92 and 93 respectively to permit the output voltage applied to needles 89 and 91 to be monitored by suitable means such as oscilloscope 73.

Also included in the present invention is a speaker which transmits an audible "click" for each output pulse so that variable resistor 31 may be used to set the pulse train rate by ear. The voltage waveform across resistor 47 is applied to capacitor 98 to produce a positive going pulse at time t.sub.1 to turn on transistor 99. At time t.sub.2 capacitor 98 will produce a negative-going pulse which will turn off transistor 99 while any portion of that pulse which extends below the zero voltage level will be conducted to ground through diode 101 which has its anode connected to the base of transistor 99. Switch 102 is an "ON-OFF" switch which is closed to permit current flow from power source 24 through speaker 103 when transistor 99 is turned on to produce an audible "click". After the pulse train rate has been set by adjusting variable resistor 31, switch 102 may be opened to avoid annoyance during use of the apparatus. Diode 101 also protects transistor 99 against power surges from the pulse train generating circuitry.

Channel 3 is similar to channels 1 and 2 with pulse generator and isolation transformer 15 receiving the output waveform as shown in FIG. 5 at capacitor 104. The base of transistor 105 receives the waveform shown in FIG. 6 and is connected to diode 106 which protects against sudden power surges from the pulse train generating circuitry. Transistor 105 is connected to transistor 107 as a Darlington pair amplifier to produce the waveform shown in FIG. 7 from transformer 108. Resistor 109 which is attenuator 18 of FIG. 1, is connected across the secondary winding of transformer 108 and also to output jack 111. When plug 112 is inserted into jack 111 the contact fingers connected to terminals 113 and 114 will be separated to interrupt the current path through resistor 115. The contact fingers connected to terminals 116 and 117 of plug 112 will be electrically connected to contact fingers connected to terminals 113 and 118 of jack 111 to supply the output voltage to needles 119 and 121. Terminals 122 and 123 of monitor jack 124 are connected to terminals 113 and 118 of output jack 111 respectively. When plug 125 is inserted into jack 124 contact fingers connected to terminals 126 and 127 will be electrically connected to contact fingers connected to terminals 122 and 123 respectively to permit the output voltage applied to needles 119 and 121 to be monitored by suitable means such as oscilloscope 73.

The output current in any channel may also be monitored by meter 128 which typically may have a zero to one hundred scale. Meter 128 may be inserted into any channel. For example, it can be connected to channel 1 by breaking the connection between resistor 54 and terminal 57 and connecting input lead 129 to the broken connection at resistor 54 while input lead 131 is connected to terminal 57. At time t.sub.1 as shown in FIG. 7, the positive portion of the waveform will cause current to flow into lead 129, through diode 132 of a diode bridge, into the positive terminal of meter 128, out of the negative terminal of meter 128, through diode 133 and out of lead 131. At time t.sub.2 as shown in FIG. 7, the negative portion of the waveform will cause current to flow into lead 131, through diode 134, into the positive terminal of meter 128, out of the negative terminal of meter 128, through diode 135 and out of lead 129. Capacitor 136 in parallel with meter 128 smooths out these voltage pulses so that meter 128 reads the average output current for channel 1. Meter 128 may also be inserted in channel 2 between resistor 79 and terminal 83 or in channel 3 between resistor 109 and terminal 113.

FIG. 8 is a front elevation view of the control panel of the present invention. "ON-OFF" switch 25 connects the power source to the pulse generating circuitry causing pilot lamp 26 to glow. Battery charge indicator 29 will indicate whether or not the batteries need to be replaced. Audio switch 102 is placed in the "ON" position while the pulse train rate is varied by adjusting variable resistor 31. Next plugs which are connected to pairs of needles may be inserted into output jacks 55, 82 and 111 which are the outputs for channels 1, 2 and 3 respectively. The tap points on resistors 54, 79 and 109 may then be adjusted individually to vary the output voltage amplitude and thereby the output current for each channel. Monitor jacks 66, 94 and 124 and speaker 103 are attached to a side panel, not shown.

In summary, the present invention generates a train of electrical impulses which are applied to pairs of acupuncture needles placed in selected portions of the body for research into acupuncture anesthesia and acupuncture therapy. A relaxation oscillator generates a trigger pulse train at a rate which may be varied between predetermined limits. A monostable multivibrator is responsive to the trigger pulses to produce pulses having a pulse width of a predetermined time interval which determines the time between the positive-going and negative-going portions of the output waveform. Separate output channels are isolated from one another and include means for adjusting the amplitude of the output waveform thereby varying the output current. Each channel is also protected against power surges and limited to a maximum output current, typically 50 microamperes.

While there is explained and illustrated the preferred embodiment of our invention, it is to be understood that many variations in the apparatus for producing the desired waveform are within the concept of the invention. Accordingly, it is to be appreciated that the invention may be practiced otherwise than as specifically illustrated and described.

Claims

1. An apparatus for generating electrical impulses to be applied to acupuncture needles placed in selected portions of the body, comprising:

means for generating a train of trigger pulses;

means for responsive to each of said trigger pulses for generating a control pulse having a pulse width of a predetermined time interval;

means responsive to each of said control pulses for generating an output pulse having a first portion of one polarity with a steep leading edge and a generally rounded crown initiated at the origin of said predetermined time interval and a second portion of the opposite polarity with a steep leading edge initiated at the end of said predetermined time interval; and

means connecting said output pulse generating means to the acupuncture

2. An apparatus as defined in claim 1 wherein said second output pulse

3. An apparatus as defined in claim 1 wherein said trigger pulse generating means includes means for varying the rate of generation of said trigger

4. An apparatus as defined in claim 3 wherein said rate varying means limits the rate of generation of said trigger pulse generating means to a

5. An apparatus as defined in claim 3 including means responsive to said control pulses for generating an audible representation of said rate of

6. An apparatus as defined in claim 1 wherein said means for generating a

7. An apparatus as defined in claim 6 including a source of direct current power having positive and negative terminals and wherein said relaxation oscillator includes a unijunction transistor having a first base connected to said negative terminal, a second base connected to said positive terminal and an emitter; a resistor connected between said positive terminal and said emitter; and a capacitor connected between said negative

8. An apparatus as defined in claim 1 wherein said means for generating

9. An apparatus as defined in claim 1 wherein said means for generating output pulses includes means for limiting output current below a

10. An apparatus as defined in claim 9 wherein said limiting means includes

11. An apparatus as defined in claim 9 wherein said limiting means limits

12. An apparatus as defined in claim 1 wherein said means for generating

13. An apparatus as defined in claim 1 wherein said means for generating

14. An apparatus as defined in claim 13 wherein said means for generating output pulses includes attenuator means connected in parallel with the secondary winding of said isolation transformer for varying the amplitude

15. An apparatus as defined in claim 14 wherein said attenuator means is a

16. An apparatus for generating electrical impulses to be applied to acupuncture needles placed in selected portions of the body, comprising:

means for generating a train of trigger pulses;

means responsive to each of said trigger pulses for generating a control pulse having a pulse width of a predetermined time interval;

a plurality of means each responsive to each of said control pulses for generating output pulses having a first portion of one polarity with a steep leading edge and a generally rounded crown initiated at the origin of said predetermined time interval and a second portion of the opposite polarity with a steep leading edge initiated at the end of said predetermined time interval; and

means connecting said output pulse generating means to the acupuncture

17. An apparatus as defined in claim 16 wherein said trigger pulse generating means includes means for varying the rate of generation of said

18. An apparatus as defined in claim 17 wherein said means for generating

19. An apparatus as defined in claim 17 including means responsive to said control pulses for generating an audible representation of said rate of

20. An apparatus as defined in claim 16 wherein said plurality of means for generating output pulses includes first, second and third output channels.

21. An apparatus as defined in claim 20 wherein said first, second and third output channels each include means for limiting output current below

22. An apparatus as defined in claim 20 wherein said first, second and third output channels each include attenuator means for individually

23. An apparatus as defined in claim 16 wherein said plurality of means for generating ooutput pulses includes first, second and third output channels each having means for protecting against power surges.