TRANSCUTANEOUS ELECTRONIC NERVE STIMULATION EQUIPMENT

Abstract: A transcutaneous electronic nerve stimulation (TENS) machine (10) has a probe (16, 17) with one or more conical tips (31, 34, 35) which provide point contact with the skin of a person or animal to accurately locate pain trigger points at the point, or between the points, of contact between the skin and the probe (16, 17), the trigger points being indicated by a high skin conductivity reading on a meter (19). A pulse generator (20) is selectively connected to the probe (16, 17) to effect treatment by directing a train of electronic pulses through the probe (16, 17) to the skin at or adjacent the pain trigger points.

Description: Title: "TRANSCUTANEOUS ELECTRONIC NERVE STIMULATION EQUIPMENT" BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates to improvements in transcutaneous electronic nerve stimulation (TENS) equipment. (2) Brief Description of the Prior Art TENS machines are used to apply electrical pulses to inflamed nerves to block the pain and so provide relief to pain sufferers . The machines have proved particularly suitable for the treatment of sport injuries and have been used on humans, horses and dogs. The presence of pain can markedly reduce the physical capabilities of a sportsman or animal in a race. The pain may not be apparent in an animal but experiments carried out on two greyhounds passed as fit by a veterin¬ arian located upto 200 inflamed nerve sites along the animals bodies . With the TENS machines presently employed, pads are placed on the skin at or adjacent the pain trigger points and the electronic pulses are applied for e.g. 30-120 minutes to obtain relief. These machines have two main problems. Firstly, the trigger points, which may be only 6mm. ( " ) across cannot be accurately located and so the pulses can only be applied in the general area of the trigger points. Secondly, the pulses are diffused through the tissue and cannot be concentrated on the trigger points for best effect. SUMMARY OF THE PRESENT INVENTION It is an object of the present invention to provide a TENS machine which can accurately locate the trigger points. It is a preferred object of the present machine to apply the electronic pulses accurately onto the trigger OMPI points . It is a further preferred object to provide a TENS machine which enables the use of alternate types of probes to suit the particular location of the trigger points . Other preferred objects of the present invention will become apparent from the following description. In one aspect the present invention resides in a transcutaneous electronic nerve stimulation (TENS) machine including: a probe means having at least one substantially conical tip to be applied to the skin of a person or animal; a meter or indicator means adapted to measure the conductivity of the skin in contact with or adjacent the conical tip or tips; and circuit means interconnecting the probe means and the meter or indicating means; so arranged that: an area, or areas, of the skin in contact with the conical tip, or between the conical tips, with the highest conductivity reading, or readings, indicates a pain trigger point, or points, at the said area, or areas, respectively. In a second aspect the present invention resides in a TENS machine including: a pulse generator to generate a train of pulses; and a probe means having at least one substantially conical tip to be applied to the skin of a person or animal; and circuit means interconnecting the pulse generator and probe means so arranged that the prove means may apply the pulses to the skin at or adjacent a pain trigger point or points . Preferably the probe means can be alternatively switched to the meter or the pulse generator so that the ^H OMPI o probe means does not have to be uncoupled and recoupled to the machine, the probe means being maintained at or adjacent the trigger point when switched from the meter to the pulse generator. The prbbe means may include a single probe, prefer¬ ably with a conical tip, which can be applied to the trigger points, the operator holding the probe and patient to provide a return path for the electronic pulses. Alter¬ natively the probe means may include a pair of probes, preferably with conical tips, fitted in a holder at a distance of e.g. 4-6cm. apart. Preferably the frequency, amplitude, wave form and pulse train length of the electric pulses may be varied to suit the particular application. BRIEF DESCRIPTION OF THE DRAWINGS To enable the invention to be fully understood, a number of preferred embodiments will now be described with reference to the accompanying drawings, in which: FIG. 1 is a schematic circuit diagram of the machine; FIG. 2 is a side view of a single probe unit; FIG. 3 is a side view of a double probe unit; and FIG. 4 is a underside view of the unit of FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the machine 10 has a control box 11 fitted with a socket 12 (e.g. of the DIN type) which receives a complementary plug 13 fitted at one end of a lead 14. The other end of the lead 14 is connected to a switch 15, 15a mounted on a probe unit 16, 16 to be described with reference to FIG. 2 and FIGS. 3 and 4, respectively. A drycell battery 18 powers the machine and is connected to a meter 19 and a pulse generator 20. These, in turn, are connected to a main selector switch 21 which connects either the meter 19 or the pulse generator 20 to the probe unit 16, 17. A meter set control 22 (i.e. a potentiometer) is connected to the meter 19. The output amplitude of the pulse generator 20 is controlled by an amplitude control 23 and the pulse frequency is controlled by a frequency control 24, to which is connected an audible indicator 25 of the pulse frequency (e.g. a piezo-buzzer) and a visual indicator 26 (e.g. a light-emitting-diode) . The continuity of the pulse train generated by the pulse generator 20 is controlled by a discontinuous pulse frequency control 27. This control enables the pulses to be generated in a continuous train or in bursts of varying frequency and/or duration. If required, the wave form of the pulses may be controlled by a waveform control (not shown) and waveforms which may be used include biphasic, spiked, square and sawtooth. Referring to FIG. 2, the single probe unit 16 has a cylindrical tubular casing 28 earthed to one pulse connection 29. The other connection 30 is connected to the probe tip 31 (having a conical nose and isolated from the casing) . An on/off switch 15 is connected to the main selector switch 21 to switch the latter from the sensing mode to the therapy mode. FIG. 3 and 4 show the spiral, or double, probe unit 17. This unit 17 has a casing 33 fitted with an on/ off switch 15a connected to the main selector switch 21. A pair of probe tips 34, 35 (each having a conical nose and isolated from the casing 33) are fitted to the under¬ side of the casing 33 and each is connected to a respective connection 36, 37 to the control box 11. The operation of the machine will now be described with reference to the single probe unit 16 of FIG. 2. The operator connects the probe unit 16 to the control box 11 and switches on the machine. By operating switch 15, the operator switches the main selector switch 21 to the sensing mode. This connects the meter 18 to the probe unit 16. He then operates the meter set control 22 to set the meter 18 to full scale deflection. The operator then places the probe tip on the patient's skin and makes conductive contact with the patient with his other hand. He moves the probe tip 31 over the skin and observes the conductivity level indic¬ ated on the meter 18. Any peak or high reading indicates a source of nerve inflammation or trigger point. Without removing the probe tip 31, he operates the switch 15 to switch the main selector to the therapy mode. Prior to use, the operator has preset the output amplitude frequency and pulse train frequency and/or duration via the controls 23, 24 and 27 respectively. The electronic pulses are applied at the trigger point via the probe tip for e.g. 30-120 seconds. The operator then operates the switch 15 to return the machine to the sensing mode and moves the probe tip 31 over the skin until another trigger point is located. The machine is then switched to the therapy mode and electronic pulses applied to the trigge point. This process is repeated until all the trigger points have been treated. As the sensing mode enables the path of an inflamed nerve to be followed from its endings to the spinal column, the path can be followed and marked with the machine in the sensing mode. The machine can be switched to the therapy mode and treatment applied progressively along the full length of the nerve. For example, where the patient has pain in the groin, the path of that nerve running from the foot to the lumbar region may be located and treatment commenced at the foot as the nerve endings are the most sensitive OMPI - ς - areas for treatment. With the spinal probe unit 17, the conductivity of the skin between the two probe tips 34, 35 is measured in the sensing mode, and the skin between the tips treated in the therapy mode. The scaling of the meter 18 by the meter set control 22 in the therapy mode limits the putput of the electrical pulses. This provides a safety factor as the output cannot exceed the limit of the meter. If the meter should fail, the output to the probes is shut-off. In addition if any other component should fail, the machine is also shut off. This ensures that the machine is compl¬ etely safe. As the operator can accurately locate the trigger points, apply the electrical pulses at or closely adjacent the trigger points, and can select the most appropriate electrical pulses to treat the inflammation, rapid and efficient therapy of the trigger points is ensured. Various changes and modifications may be made to the embodiments described without departing from the scope of .the present invention as defined in the appended claims

Claims: -V CLAIMS : 1. A transcutaneous electronic nerve stimulation (TENS) machine including: a probe means having at least one substantially conical tip to be applied to the skin of a person or animal; a meter or indicator means adapted to measure the conductivity of the skin in contact with or adjacent the conical tip or tips; and circuit means interconnecting the probe means and the meter or indicating means; so arranged that: an area, or areas, of the skin in contact with the conical tip, or between the conical tips, with the highest conductivity reading, or readings, indicates a pain trigger point, or points, at the said area, or areas, respectively. 2. A machine as claimed in Claim 1 and further including: a pulse generator to generate a train of pulses; and circuit means interconnecting the pulse generator and probe means; so arranged that: the probe means applies the pulses to the skin at or adjacent the pain trigger point, or points. 3. A machine as claimed in Claim 2 wherein: the probe means is maintained with its conical tip, or tips, in contact with the skin at or adjacent the pain trigger point or points as the probe means is switched between the meter or indicating means to locate the trigger point or points, and the pulse generator to treat the trigger point or points . 4. A machine as claimed in Claim 1 wherein: the probe means has a single conical tip having a very small area of contact with the skin; and the operator holding the probe and the patient forms one part of the circuit interconnecting the probe means and the meter or indicating means. O PI 5. A machine as claimed in Claim 1 wherein: the probe means includes a pair of conical tips each having a very small area of contact with the skin, so arranged that a pain trigger point, when located, will be in the area between the tips. 6. A machine as claimed in Claim 2 wherein: the frequency, amplitude, waveform and/or pulse train length of the pulses generated by the pulse generator are variable to suit the treatment of different pain trigger points. 6. A transcutaneous electronic nerve stimulation (TENS) machine substantially as hereinbefore described with reference to the accompanying drawings.

Inventors: BEALE ALAN DAVID, BEALE, ALAN, DAVID
Applicants: BEALE ALAN DAVID, BEALE, ALAN, DAVID
Application year: 1983
Main classification: A61N1
IPC codes: A61B5, A61N1