Electrical Therapeutic Device

Abstract

A transistorized electrical sleep-inducing device includes a current regulating buffer which protects the patient from excessive current, when operated on conventional AC power and maintains the current substantially constant regardless of variations in the patient's body resistance. The patient is also protected by sensitive fuses, an isolation transformer, careful grounding, a floating circuit and a substantial resistance connected in series with him. A peak reading volt meter precisely indicates the pulse amplitude by utilizing a peak detector circuit connected to a high input impedance, such as balanced bipolar transistors or a unipolar field effect transistor (FET) differential amplifier. A frequency band selector and scanner, connected to the pulse generator, varies the applied frequency to suit the patient's response. The output is contacted to various portions of the patient's anatomy in accordance with his particular symptoms and treatment therefor.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an electrical therapeutic device and more particularly to one in which an electrical current is directly applied to a selected portion of the patient's anatomy through a contacting electrode. It more particularly related to such a device for inducing sleep or relaxation.

2. Description of the Prior Art

Electrical sleep-inducing devices have been therapeutically used in various European countries for many years and quite extensively in the U.S.S.R. An existing type of such apparatus utilizing vacuum tubes is described in U.S. Pat. No. 3,160,159. Battery-operated devices utilizing transistors are described in U.S. Pat. Nos. 3,255,753 and 3,388,699. U.S. Pats. Nos. 3,050,695, 3,241,557 and 3,295,528 relate to battery-operated transistorized pulse generators for human treatment. An object of this invention is to provide a simple, economical and compact low frequency pulse generating device for human therapeutic treatment which is safe, self-regulating, readily controllable and which clearly indicates the character of the pulse applied to the patient. Another object is to provide such a device which is particularly effective for inducing sleep and relaxation.

SUMMARY

A transistorized electrical sleep-inducing device including a current-regulating buffer, which protects the patient from excessive current when operated on conventional AC power and maintains the current substantially constant regardless of variations in the patient's body resistance. The patient is also protected by sensitive fuses, an isolation transformer, careful grounding, a floating circuit and a substantial resistance connected in series with him. A peak reading volt meter precisely indicates the pulse amplitude applied to the patient by utilizing a peak detector circuit connected to a high input impedance, such as balanced bipolar transistors or a unipolar field effect transistor (FET) differential amplifier. A frequency band selector and scanner, connected to the pulse generator, varies the applied frequency to suit the patient's response. The output is contacted to various portions of the patient's anatomy in accordance with his particular symptoms and treatment therefor.

BRIEF DESCRIPTION OF THE DRAWING

Novel features and advantages of the present invention will become apparent to one skilled in the art from a reading of the following description in conjunction with the accompanying drawing wherein similar reference characters refer to similar parts and in which:

FIG. 1 is a schematic block diagram showing an embodiment of this invention and illustrative wave forms;

FIG. 2 is a schematic diagram of the embodiment of this invention shown in FIG. 1;

FIG. 3 is a schematic diagram of another and generally improved embodiment of the invention shown in FIGS. 1 and 2; and

FIG. 4 is a schematic diagram of a modified portion of the embodiment of this invention shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 is shown a block diagram of a sleep-inducing device 10, which is one embodiment of this invention. Device 10 includes the following major components indicated by the correspondingly designated blocks: power supply 12, current regulator and buffer 14, pulse generator 16, metering circuit 18 and output control 20. Characteristic wave forms 22 and 24 (later described) are generated within and in the output from pulse generator 16. Power supply 12 includes AC source 26, DC source 28 and voltage regulator 30. Pulse generator 16 includes monostable multivibrator 32, relaxation oscillator 34 and frequency band selector and scanner 36. Metering circuit 18 includes high impedance section 38 (for example high impedance differential amplifier 38), peak voltage detector 40 and meter M. Output control 20 includes timed switch 42, regulated DC bias input line 21 from DC source 28 in power supply 12, isolating resistor R38, outlet plug 44 and other components later described. Amplitude control R8 is a current regulator and Buffer 14 is functionally a part of the output control.

FIG. 2 is an overall schematic diagram of sleep-inducing device 10 showing in detail the various components of the FIG. 1 block diagram. Power supply 12 is at the left-hand side of FIG. 2. It is alternatively operated through a standard AC input section 46 or by a 45-50 volt DC source. This circuit can be operated by 117 volt AC or by a 45-50 volt center-tapped rechargeable battery by slide switch S8 application. If used with 117 volt AC main, a number of safety precautions eliminate all hazards. These precautions are: both lines have fast blow fuses, 71 and 72, isolation transformer 26, chassis grounded to ground wire of power line, floating circuit, the buffer stage 14 and finally, to some extent, R42. The supplies are well regulated. The power supply can also operate with 220 volts, 50 cycle, for European or Japanese use.

Pulse generator 16 includes relaxation oscillator 34. The operation of relaxation oscillator 34, FIG. 2, and its trigger pulse output 22, FIG. 1 is set forth in the following: Current thru resistor R19 charges capacitors C.sub.6, C.sub.7 or C.sub.8 (depending on frequency selector switch position) to a voltage level sufficient to forwardly bias emitter, "E", of unijunction transistor V8 and let the current flow through it to Base 1, "B 1". It is at this time that the unijunction transistor shows a negative resistance and the sharp pulse 22 of FIG. 1 appears at the Base 1. This pulse is used for triggering the monostable multivibrator to metastable (unstable) state to generate the required pulse. The frequency of the trigger pulse 22 is related to the product R14 C5. In FIG. 2, relaxation oscillator 34 consists of unijunction transistor V8; switches S5 and S7; capacitors C.sub.6, C.sub.7 and C.sub.8 ; resistors R17, R18, R23, R24 and R25; variable resistors R20, R21, and R22; controls R19, R19A and R41 and the DC motor, Mot.

Switch S5 is a band selector switch that selects one of the three bands of frequencies, (2 to 10, 10 to 50 and 50 to 150 CPS). For example, band 2 to 10 c.p.s. consists of C.sub.6, R23, R20 and R19. At the 2 to 10 c.p.s. branch when control R19 is set at maximum, it generates 2 c.p.s. By increasing R19, the pulse decreases until minimum setting (10 c.p.s.) is reached. R20, R21 and R22 are used to compensate for other component tolerances.

Slide switch S7 may be switched to "scan" position where R19 is replaced by R19A and the DC motor, Mot., becomes energized. Then the DC motor, Mot., rotates the control R19A and automatically changes the frequencies within a band at a very slow speed. The speed of the motor is controlled by R41.

The monostable multivibrator 32 consists of transistors V6 and V7, resistors R12, R13, R14 and R15 and capacitor C.sub.5. R14 is chosen to hold V6 in saturation in the stable state. The cross-coupling resistor R12 holds V7 off. When a trigger pulse 22 (FIG. 1) brings the circuit into a condition in which both transistors are in the active state, regenerative switching action will occur, and the circuit rapidly switches to metastable state where the state of each transistor is reversed. That is, V7 saturates and V6 cuts off. At this time the collector of V6 has an output pulse 24 of a predetermined duration of time T = R14 C.sub.5 1n2 seconds. During this time the base ground voltage of V6 is increasing exponentially (C5 being charged thru R14 toward B+) up to a point where its value can bring V6 from the cut off to the active region, whereby (due to regenerative transistor action) the circuit rapidly switches from metastable to its stable state. The metastable time is T = 0.5 millisecond and it is during this time that the collector of V6 provides the pulse used as part of the voltage input to the patient.

Constant current regulation and buffer 14 consists of a PNP transistor (V4), a reference voltage (Z3), volume control (R8) and resistors R9 and R10. The patient is connected as an impedance load to the collector of V4 through intermediaries. The circuit is active only when the pulse is present. Since it holds the current thru the collector at a constant rate, the output voltage corrects itself, with any biological change in the patient occurring because of a change of his body's resistance. For example when the patient is at rest, his resistance is decreased. Then the same current impressed across the reduced resistance produces less voltage and this is what the patient needs at this stage. This circuit also serves as a buffer stage as previously described.

Metering circuit 18 includes high impedance input section 38 (for example balanced differential amplifier 38) peak voltage detector 40 and meter M including switches S2 and S3. The high input impedance section comprises a Darlington differential amplifier 38. At low frequency it is very hard to measure the amplitude of the pulse through transistor circuits because of their inherent low input impedance. However, differential amplifier 38 is so designed that it presents a high input impedance of approximately 10 megohms to the pulse trend. This circuit consists of transistors V9, V10 and V11; Resistors R26, R27, R28, R29, R30, R31, R40 and control R32; capacitor C14; diodes D10 and D11; switches S2 and S3.

Normally closed push-open switch S3 serves to interrupt the entrance of the pulses to the metering circuit to obtain zero adjustment in the metering circuit by balance control R32. Switch S2 can be switched to DC position to measure the value of the DC component to the patient.

Transistors V10 and V11 along with resistor networks R30, R31, R32 and R40 yield the high input impedance so necessary for a low frequency peak reading volt meter. The properties of this voltmeter are: high input impedance, high sensitivity and inexpensive and practical structure.

Output control section 20 includes timed switch 42 including switch S6 and timer T which permits setting of device 10 for any convenient time such as from one to sixty minutes. The output section also includes output plug 44 to which the output means to the patient, such as a headband or contact electrode, is connected. For example, negative pole 48 is applied against ocular regions and positive pole 49 against the back of the head at the base of the brain. Line 21 connects a regulated DC bias from DC power supply 28. Resistor R38 provides pulse and bias isolation. Polarity switch S4 facilitates quick reversal of polarity. Potentially R8 in current regulator and Buffer 16 is functionally a part of the output control in that it affords variation in pulse amplitude.

Pulse generator 16 also includes frequency selector and scanning circuit, 36. This circuit is used because some patients may respond more favorably to a gradual variation in frequency. For example, this apparatus has three frequency ranges, namely: 2 to 10, 10 to 50 and 50 to 150 c.p.s. In the 2 to 10 c.p.s. range with automatic frequency change, it would introduce 2, 3,- 10 c.p.s. and keep repeating itself.

OPERATION

The doctors using this type of apparatus spend a lot of time adjusting the controls until they come to a point where a particular patient feels relaxed and comfortable. Psychiatrists are usually frequented by the same patient a number of times and then can collect clinical data by observing the reaction of a certain patient under treatment. In order to save time and enable the doctor to collect data for analysis, the apparatus should have a metering circuit for reading the relative amplitude of the pulse applied and the changes that occur in the patient from time to time. Hence, the peak reading metering circuit 18 is provided.

The amplitude of the pulse applied to each patient is automatically indicated. At a certain point the person under treatment and his doctor feel that the setting of amplitude control is just right for relaxation. As the minutes go by, the patient's body chemistry reacts to the pulses and the pulses become less and less effective, which the patient can feel. This reduction in effectiveness causes the patient to lose the relaxation that he initially felt, particularly if his thought patterns are unfocused and irregular. Hence, a method of compensation with his physical reaction is used. This is current regulator and buffer 14. The frequency control 36 and the amplitude control R8 of this machine are installed in a separate module that is normally part of the machine, but it is removable and is connected to the machine by a four foot length of wire or cable. This is to permit some patients to operate the machine remotely.

FIG. 3 shows another and generally improved embodiment 10A of this invention which is generally similar to FIG. 2 except that it is operated only on AC and includes a special frequency band selector and scanning circuit 36A. Circuit 36A has three bands of frequency: 2-10 cycles/sec.; 10-50 cycles/sec.; and 50-250 cycles/sec. Switch S-5 selects one of these three bands. The operator can select a single frequency within each band through R19, by turning switch S-7 to manual, or he can set switch S-7 to automatic, which scans all frequencies within the selected band. When switch S-7 is on automatic scan, the speed of scanning can be selected from 6 to 60 r.p.m. This feature is useful in psychiatric research by assisting the doctor in efficiently establishing a patient's response to various frequencies.

FIG. 4 shows an alternative high input impedance section 38B for metering circuit 18. It replaces bipolar transistors V9, V10 and V11, with unipolar field effect transistors (FET). In this case one FET replaces V9 and another replaces both V10 and V11. Since an FET has a very high input impedance--essential to the metering circuit of this type--the Darlington bridge of V10 and V11, which is solely for high input impedance can be replaced by one FET. The general high input impedance characteristics of the differential amplifier do not change.

Claims

I claim:

1. An electrical therapeutic device comprising the following components in electrical connection with each other: a power supply, a current regulating buffer, a pulse generator and output means for applying electrical pulses generated by said device to a patient; said power supply being connected to said pulse generator, said pulse generator being connected to said current regulating buffer and said current regulating buffer being connected to said output means; DC bias means connected between said current regulating buffer and said output means; said current regulating buffer comprising a transistor and circuit means connecting said transistor to said output means and said DC bias means whereby output current transmitted through said transistor is made independent of the impedance represented by said patient for limiting said current and holding it substantially constant regardless of biological variations in the resistance of said patient.

2. A device as set forth in claim 1 wherein said transistor has an emitter, a collector and a base, a source of a reference voltage being provided, and said circuit means connects said output means to said collector, said power supply to said base and said source of a reference voltage to said emitter.

3. A device as set forth in claim 2 wherein said transistor is of the PNP type.

4. A device as set forth in claim 2 wherein said source of a reference voltage comprises a solid state reference voltage diode.

5. A device as set forth in claim 4 wherein a variable resistor is also connected to said emitter.

6. A device as set forth in claim 1 wherein a peak reading volt meter circuit having a high input impedance is connected to said circuit whereby the amplitude of said pulses are reliably indicated.

7. A device as set forth in claim 6 wherein said peak reading volt metering circuit comprises a peak detector circuit and high impedance input means connected thereto.

8. A device as set forth in claim 7 wherein said high input impedance means comprises a high input impedance differential amplifier.

9. A device as set forth in claim 8 wherein said high input impedance differential amplifier utilizes field effect transistors.

10. A device as set forth in claim 8 wherein said differential amplifier includes a Darlington follower.

11. A device as set forth in claim 8 wherein said high input impedance differential amplifier comprises a balanced bipolar transistor differential amplifier.

12. A device as set forth in claim 8 wherein said high input impedance differential amplifier comprises a unipolar field effect transistor differential amplifier.

13. A device as set forth in claim 1 wherein said pulse generator includes a frequency band selecting means whereby a band of predetermined frequency is selected and utilized for treatment.

14. A device as set forth in claim 13 wherein said pulse generator also includes a frequency scanning means connected to said frequency band selecting means whereby the output of said generator is caused to gradually vary in frequency within said band for determining the optimum frequency to treat said patient.

15. A device as set forth in claim 14 wherein said frequency selecting means comprises a variable resistor and motor means connected to said resistor for causing its resistance to gradually vary whereby said frequency is varied within the selected band.

16. A device as set forth in claim 1 wherein output means is connected to said current regulating buffer, and isolating means is connected therebetween.

17. A device as set forth in claim 16 wherein said isolating means comprises a relatively high impedance resistor.

18. A device as set forth in claim 1 wherein polarity reversing means is connected to said output means.

19. A device as set forth in claim 1 wherein said current regulating buffer also includes a variable resistor whereby the amplitude of the pulse applied to said patient may be varied.