United States Patent c191
`Jalinous
`
`[54] APPARATUS FOR THE MAGNETIC
`STIMULATION OF CELLS OR TISSUE
`
`[76]
`
`Inventor: Reza Jalinous, 22 Maes-y-felin,
`Fforestfach, Swansea, United Kingdom,
`SAS 5DW
`
`[21] Appl. No.:
`
`532,612
`
`[22] PCT Filed:
`
`Feb. 10, 1995
`
`[86] PCT No.:
`
`PCT/GB95/00262
`
`§ 371 Date:
`
`Dec. 14, 1995
`
`§ 102(e) Date: Dec. 14, 1995
`
`[87] PCT Pub. No.: W095/21655
`
`PCT Pub. Date: Aug. 17, 1995
`
`[30]
`
`Foreign Application Priority Data
`
`[GB] United Kingdom ................... 9402545
`
`Feb. 10, 1994
`Int. CI.6
`....................................................... A61N 1/00
`[51]
`[52] U.S. CI . ............................................... 600/13; 128/897
`
`11111 IIIIIIII II IIIII IIII IIII IIUI lllll lllll lllll lllll 11111111111111111
`US005718662A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,718,662
`Feb. 17, 1998
`
`[58] Field of Search ..................... 600/9-15; 128/897-98
`
`[56]
`
`References Cited
`
`FOREIGN PATENT DOCUMENTS
`
`6/1988 European Pat. Off ..
`0271174
`1401682 10/1965 France.
`2676930 12/1992 France .
`A3244582 12/1984 Germany .
`2261820
`6/1993 United Kingdom .
`
`Primary Examiner-John P. Lacyk
`Attome)\ Agent, or Firm-Nixon & Vanderhye P.C.
`
`[57]
`
`ABSTRACT
`
`A stimulator for neuro-muscular tissue having a stimulating
`coil which is energized by discharging capacitors at different
`times in parallel connected discharge circuits so as to
`provide amplitude and/or frequency modulation of the
`stimulating pulses.
`
`3 Claims, 2 Drawing Sheets
`
`4
`
`CAPACITOR 0
`
`CAPACITOR E
`
`~ ·-!)~L
`~1----.-□rcJ·' -C~~ ~
`
`DISCHARGE
`CONTRCl.. F
`
`~ ~
`10b
`
`CAPACITOR H
`
`DISCHARGE
`CONTROLH
`
`Allergan EX1016
`Page 1
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`

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`
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`
`Allergan EX1016
`Page 2
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`

`

`U.S. Patent
`
`Feb. 17, 1998
`
`Sheet 2 of 2
`
`5,718,662
`
`FIG.2
`
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`
`Allergan EX1016
`Page 3
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`

`

`1
`APPARATUS FOR THE MAGNETIC
`STIMULATION OF CELLS OR TISSUE
`
`5,718,662
`
`2
`time varying magnetic fields produced by the application of
`a multiplicity of capacitor discharge pulses to a stimulating
`coil, which may be, for example, specially shaped to fit the
`This invention relates to apparatus for magnetically
`cranium of a patient. For example, the coil maybe in the
`stimulating neurones and in particular neuro-muscular tissue s form described in our published British Patent Application
`by inducing therein electric current using time varying
`GB-A-2261820.
`magnetic fields, and for similar pwposes such as the stimu(cid:173)
`In the illustrated system, the apparatus comprises two sets
`lation of cells in cell cultures. Broadly, the invention con(cid:173)
`of capacitors 3 each having a respective, independently
`cerns a magnetic stimulator which is capable of producing
`controllable discharge control, connected in parallel to pro(cid:173)
`pulse trains of which both frequency and amplitude are
`vide one common output for each set of capacitors. The two
`controllably variable and particularly concerns a stimulator
`outputs maybe used to drive different coils or maybe coupled
`comprising a multiplicity of capacitor discharge units of
`in parallel to drive a single stimulating coil thereby to extend
`which the outputs can be coupled in parallel.
`the range of variation of amplitude or frequency of the pulse
`In a preferred form of the invention, a multiplicity of
`trains which can drive the stimulating coil.
`discharge units, each of which is capable of independent
`A mains power input terminal 1 is coupled to provide
`operation and is disposed to provide an output in parallel 15
`alternating current to two chargers :2a and 2b. Each of these
`with the output of one or more other units so as to provide
`various outputs such as pulses of greater power or pulse
`chargers may comprise, in any desired circuit configuration,
`strains of different frequency. Each unit may be coupled to
`a transformer rectifier circuit and some means of controlling
`a charging circuit and may include at least one pulse forming
`output voltage. Such circuits are well known to those skilled
`capacitor and a controllable discharge circuit.
`20 in the art and will not be described in detail.
`The various units may be supervised by an electronic
`Each charger could be connected to charge a respective
`control circuit which may itself be controllable by means of
`capacitor but for preference in the present embodiment each
`a remote controller.
`of the two chargers charges a respective pair of the capaci(cid:173)
`In a preferred form of the invention, the outputs from the
`tors 3, the charger :2a being connected to charge capacitor A
`discharge units maybe combined and fed to an output so that, 25
`and capacitor B and charger 2b being connected to charge
`for example, two of the units may provide outputs which can
`capacitor C and capacitor D.
`be coupled to a first output terminal and two or more further
`In like manner, a second power input la provides power to
`units may provide an output which can be coupled to a
`two chargers 2c and 2d respectively, the charger 2c being
`second output terminal. This arrangement enables the use of
`connected to charge capacitor E and capacitor F and charger
`either one or two stimulating coils with independent pulsing
`2d being connected to charge capacitor G and capacitor H.
`control. It also provides for a certain fault tolerance, so that
`if one or two units failed it would still be possible to utilize
`Thus the capacitors may by virtue of the control by the
`one of the outputs of the circuit.
`chargers 2a to 2d be charged with a variety of charges but
`The stimulating power of each unit can be controlled by
`for simplicity it will be supposed that the various capacitors
`varying the energy initially installed in the unit by variation
`are of the same capacitance and store the same charge.
`of the stored capacitor voltage. Thus a multiplicity of 35
`Each of the capacitors is provided with a respective
`different amplitudes can be selected, one for each of the
`discharge control 4. The discharge controls are controllable
`plurality of magnetic stimulator units for each pulse train
`at independently selectable times by means of a controller 5,
`thereby to provide amplitude variation or modulation of the
`which by means of an interface 6 may be controlled
`pulse train. Random variation could also be employed.
`remotely by means of a remote control unit 7 or locally by
`The use of a multiplicity of units in parallel enables the 40
`means of a trigger input 8. The controller 5 may be of any
`spacing between successive stimulating pulses to be very
`desired construction, it being sufficient for the purposes of
`short, even zero. Frequency modulation can be provided by
`the present invention that the controller 5 can provide eight
`variation of the interpulse spacing.
`switching signals at independently controllable times, for
`The combined outputs from a multiplicity of units may
`operation of the discharge controls 4. The controller 5 may
`also be such as to increase output power by simultaneous or 45
`include a microprocessor or may be controlled using a
`nearly simultaneous multi-channel discharge.
`suitable interface from the output of a computer.
`Each unit may typically recharge in a cycle which lasts
`approximately two to four seconds depending on the power
`The output terminals 9 and 9a, one for each set of
`level, stored energy and charging rate. It is feasible to
`capacitors, may be coupled in parallel to drive a single
`increase the discharge repetition rate by at least a factor of
`stimulating coil 10 or be connected separately to respective
`N where N is the number of capacitors, by discharging all 50
`stimulating coils 10a and 10b.
`the capacitors in a time sequence. Thus at lower power levels
`According to the timing of the discharge control signals
`and for a two second recharge time, a 4 Hz discharge
`available from the controller 5, the pulse outputs may be
`repetition rate is possible for an eight capacitor system.
`combined so as to provide one or more pulses of variable
`More versatile systems containing additional capacitors
`amplitude and spacing. For example, four capacitors may be
`enabling a wider range of amplitude and frequency variation 55
`discharged at evenly spaced times to provide a train of four
`can be envisaged.
`pulses. Two pairs of capacitors may be discharged at respec-
`tive times to provide a pulse pair of higher amplitude or a
`multiplicity of capacitors may be discharged simultaneously
`60 to provide a single pulse.
`The cycle of control of discharge may be repetitive and
`the pulse timing can be adjusted within each cycle so as to
`provide a substantially continuous stream of pulses exhib(cid:173)
`iting either frequency modulation amplitude modulation or
`65 a combination of both frequency and amplitude modulation.
`FIG. 2 illustrates a detailed schematic of several capaci(cid:173)
`tors 11 etc corresponding to the capacitors A, B etc in FIG.
`
`BRIEF DESCRIPTION OF TIIE DRAWINGS
`FIG. 1 is a schematic representation of a magnetic stimu(cid:173)
`lator according to the invention; and
`FIG. 2 is a more detailed schematic diagram of part of a
`stimulator according to the invention.
`
`10
`
`30
`
`DETAILED DESCRJPTION OF PREFERRED
`EMBODIMENfS
`FIG. 1 illustrates an apparatus for providing magnetic
`stimulation of neuro-muscular tissues by the application of
`
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`5,718,662
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`3
`1. Each capacitor forms a module with an associated dis(cid:173)
`charge control. Each of the discharge units (modules) A, B
`in FIG. 2 is capable of providing a stimulating pulse in the
`coil 10 of which only one needs description. The modules A,
`B etc maybe all the same. In this embodiment a storage 5
`capacitor 11 is discharged by means of a series switch 12
`which is controllable by means of control signals from the
`controller (not shown in FIG. 2) and is preferably but not
`essentially constituted by a controlled rectifier such as a
`thyristor. In series with the capacitor 11 and switch 12 is a 10
`current limiter which may be an inductor 13. The output port
`of each discharge unit is connected in parallel with the other
`output ports of the other discharge units and the common
`output lines are shown as connected to a stimulating coil 10.
`Only the operation of a single discharge control circuit 15
`need be described in detail.
`The switch 12 of the first channel is normally open, i.e.
`non-conductive, the capacitor 11 being charged by a respec(cid:173)
`tive charger to a desired voltage. In parallel with the capaci-
`tor may be a branch containing a diode 14 and a resistor 15. 20
`The diode is reverse-biased when the capacitor 11 is
`charged.
`At the desired time the switch 12 is rendered conductive
`by a control signal at its gate. The discharge current from the 25
`capacitor flows through the stimulating coil 10. As energy is
`tranferred from the capacitor to the stimulating coil the
`voltage across the capacitor diminishes and eventually
`reverses polarity. At this point the diode becomes forward(cid:173)
`biased and begins to conduct. The discharge current falls
`until it reaches zero. The switch 12 maybe made non(cid:173)
`conductive at this time.
`The diode 14 and resistor 15 act to limit the voltage
`reversal. For small values of the resistor 15 the voltage
`reversal is clamped to a low value. If desired, the diode 14
`or the resistor 15 or both maybe omitted. The various circuit
`configurations determine the shape of the waveform
`obtained.
`Inductor 13 is employed to limit the rate of change of
`current and ultimately control the-peak discharge current in
`the case of a short circuited output. The use of an inductor
`is quite useful because it enables an inherently parallel
`system with short circuit protection. In some cases, owing to
`the of the spurious inductance possessed by all wiring and
`components, the total spurious inductance may be sufficient 45
`to provide short circuit protection.
`
`4
`The switch 12 is preferably a thyristor but other switching
`devices such as thyratrons, triacs, transistors and relays
`might be used. Controllable switches, particularly control(cid:173)
`lable rectifiers may be used in place of the diodes 14.
`
`If desired, a reverse diode 16 in series with a resistor 17
`may comprise a branch in parallel with the coil 10; these
`components have the same purpose as the diodes 14 and
`resistors 15.
`I claim:
`1. A stimulator circuit for providing a pulse output for a
`stimulating coil for the stimulation of cells or tissues by
`means of a time varying magnetic field produced by said
`stimulating coil in response to said pulse output, said stimu-
`lator circuit comprising:
`a plurality of discharge channels, each channel compris(cid:173)
`ing a respective charge storage capacitor and electri(cid:173)
`cally controllable means for discharging said respective
`capacitor;
`means for coupling said discharge channels in parallel to
`said stimulating coil so as to couple said pulse output
`thereto; and
`means for controlling said electrically controllable means
`of said channels so as to control the timing of the
`discharging of the capacitors in said channels whereby
`to provide amplitude or frequency modulation of said
`pulse output.
`2. A stimulator circuit according to claim 1 in which each
`30 channel comprises the respective capacitor, a controllable
`rectifier and a current limiting inductor in series with the
`capacitor and a circuit branch including a reverse diode and
`a resistor in parallel with the capacitor.
`3. A stimulator circuit according to claim 1 comprising a
`35 further plurality of discharge channels each including a
`respective storage capacitor and electrically controllable
`means for discharging said respective capacitor for produc(cid:173)
`ing a pulse output for a further stimulating coil, said means
`for coupling providing coupling of said further plurality of
`40 discharge channels to said further stimulating coil and said
`means for controlling providing control to the electrically
`controllable means of said further plurality of discharge
`channels so as to control the timing of the discharging of the
`capacitors of said further plurality of discharge channels.
`
`* * * * *
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