Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
  • A61N1/36128—Control systems
  • A61N1/36146—Control systems specified by the stimulation parameters
  • A61N1/36182—Direction of the electrical field, e.g. with sleeve around stimulating electrode
  • A61N1/36185—Selection of the electrode configuration
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/372—Arrangements in connection with the implantation of stimulators
  • A61N1/37211—Means for communicating with stimulators
  • A61N1/37235—Aspects of the external programmer
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/372—Arrangements in connection with the implantation of stimulators
  • A61N1/37211—Means for communicating with stimulators
  • A61N1/37252—Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
  • A61N1/37288—Communication to several implantable medical devices within one patient

Definitions

• the invention relates to the control of the human body and more particularly to the stimulation and / or the measurement of physiological quantities on sites of the sensorimotor system of the human body, with the aim of compensating for sensorimotor deficiencies following an accident, or as a result of an illness.
• the application finds particular application in neural stimulation, and more particularly stimulation of the peripheral nervous system. However, it is perfectly applicable to other types of stimulation, such as surface stimulation, epimysial stimulation, or functional electrical stimulation applied to the brain and / or spinal cord.
• Stimulation or measurement can be performed on any physiological structure capable of generating or reacting to an electrical signal, most often in the form of an action potential.
• the axons grouped into fascicles and then nerves, the neurons themselves located in the brain or the spinal cord, the cardiac, skeletal muscle fibers or certain smooth muscles, the sensory organs, are all structures that can be either observed, be stimulated.
• the invention relates to this second type of research, and allows to restore or modulate certain motor, sensory or organic activities of the human body through a device and a neural stimulation system that comes to provide or rehabilitate the deficient control of the nervous system.
• Electrodes rely on one or more electrodes implanted in the human body, which can be controlled to apply or measure a current or voltage at a nerve or target structure mentioned above.
• the invention improves the situation.
• the invention provides an implantable control device in a human body, comprising a control unit and at least one electrode.
• the unit of control is connected to the or each electrode to control it in stimulation and / or measurement.
• the control unit comprises:
• a memory storing defined configuration data to allow the configuration of the or each electrode in correspondence of identifiers
• a memory storing program data describing a time profile in correspondence of identifiers
• a sequencer arranged to receive an ordered plurality of pairs each comprising an electrode configuration identifier and a program identifier, and to selectively activate the executor with the electrode and program configuration couples designated by the pairs of identifiers received as input, depending on their order and the clock.
• the invention also relates to an implantable control system in a human body, comprising a driver and at least one device as described above, connected in a wired bus-type network, in which the driver is arranged to send said plurality of couples. identifiers to the sequencer of said device.
• FIG. 1 represents a diagram of a control system of the human body according to the invention implanted in a human body
• FIG. 2 represents a diagram of a device for controlling the human body of the system of FIG. 1,
• FIG. 3 represents a diagram of the distribution of the poles of an electrode type of the device of FIG. 2,
• FIG. 4 represents a block diagram of part of the device of FIG. 2
• FIG. 5 represents an example of data stored in one of the elements of FIG. 4,
• FIG. 6 represents an example of data stored in another of the elements of FIG. 4,
• FIG. 7 represents a block diagram of a neural stimulation driver of the device of FIG. 1, and
• FIG. 8 represents an operating diagram of the pilot of FIG. 7.
• FIG. 1 represents a diagram of a neural stimulation system 2 implanted in a human body 4.
• the neural stimulation system 2 comprises an external control 6, a pilot 8, and neural stimulation devices 10.
• the external control 6 and the driver 8 communicate by a wireless signal, of the inductive link type or of the radiofrequency (RF) communication link type.
• RF radiofrequency
• the pilot 8 is implanted in the upper part of the body 4. It may for example be housed at the level of the clavicle or the abdomen of the body 4. It may be housed elsewhere, as will be known appreciate the skilled person.
• a device 10 is located at the level of the bladder, and two devices 10 are respectively disposed in each of the left and right legs.
• the driver 8 is connected to the various neural stimulation devices 10 by means of a bus 11.
• the bus 11 is a set of conductive wires (for example, a bi-wired cable approved for the heart rate IS-1), which transport both the energy to supply the devices 10, and the data to be transmitted between the driver 8 and the devices 10.
• the bus 11 may be dedicated to the transport of information, and not to carry energy.
• the bus 11 is made in the form of conductive wires. However, in other variants, it could be implemented by a radiofrequency link, an acoustic link, an inductive link or other. As will be seen later, the bus 11 is asynchronous in the example described here, that is to say that the bus 11 does not carry a synchronization signal (like a clock signal for example) devices 10. Thus, the bus 11 is implanted in the body 4 in the areas that one wishes to control, which may be close to the nerves or muscles concerned, and each device 10 is then connected to the bus 11. The bus 11 thus represents a kind of backbone on which are grafted the devices 10, and each device 10 connected is a node of the bus 11.
• the neural stimulation is entirely controlled by the pilot 8. This approach represents a radical contrast with the approaches known to date.
• the stimulations considered by the invention for example those with a selective character, locally require a precision of the order of one microsecond, each device 10 having its own clock.
• the drift of the clock devices 10 is present in this context, and its influence should not be neglected.
• FIG. 2 represents an example of a neural stimulation device 10.
• the device 10 comprises a control unit 12 and four electrodes 14 respectively referenced 14a, 14b, 14c and 14d.
• control unit 12 can provide both a stimulating role and a measuring role.
• Each electrode 14 is arranged at a selected zone of the nervous or muscular structure to be stimulated.
• the four electrodes 14 represented here non-exhaustively illustrate various geometrical configurations of the contacts, associated with suitable mechanical structures: the electrode 14a is of the annular type, the 14b of the intrafascicular type, the 14c electrode of the flat type, and the electrode 14d is of the matrix type.
• the electrode 14a comprises three rings 16 with four poles each, which gives a total of 12 poles.
• the electrode 14a may also comprise a smaller number of rings, for example 3, each with 4 poles, or another distribution of the number of rings and poles per ring, especially in the context of cochlear stimulation.
• the total number of poles may vary with the chosen configuration, and may be greater than or less than 12. This number typically varies from 2 for bipolar or monopolar stimulation with reference, to more than 24 for cochlear application.
• a device 10 comprises a number of electrodes 14 between 1 and 6, all of which are controlled by a single control unit 12, each electrode comprising between 1 and 12 poles.
• the electrodes are neural, in other applications, they could be epimysial, intramuscular, intracerebral, intrafascicular, cortical or other.
• FIG. 3 represents a schematic view of the disposition of a ring of an electrode 14 around a nerve 18.
• the nerve 18 comprises four fascicles 19 each having several axons 20.
• the poles 22 of the ring 16 are arranged regularly around the nerve 18, so that each pole 22 is substantially facing a set of axons 20.
• the control unit 12 of this device 10 emits an electrical stimulus at one or more poles 22 of a ring 16 of an electrode 14 of the device 10, and the subset of axons 20 opposite this set of poles 22 is thus stimulated.
• FIG. 4 shows the architecture of a control unit 12.
• the control unit 12 can manage one or more electrodes 14, for purposes of either stimulation or measurement, via the analog-digital and digital-analog stages 42.
• the control unit 12 comprises two main interfaces.
• the first interface, referenced 40 is the communication interface with the bus 11. This interface 40 makes it possible to receive the pilot's energy and control signals 8.
• the second interface, reference 42 is the communication interface with the electrode 14 which is managed by the control unit 12.
• This interface 42 controls the stimulation of the axons 20 by the poles 22.
• the interface 42 is integrated in a digital / analog converter which is assimilated, and whose role will be explained later.
• the control unit 12 is a very low consumption circuit and clocked by a clock 44 whose speed is of the order of 1 to 4 MHz. This allows the control unit 12 to have an accuracy of the order of one microsecond.
• the asynchronous bus 11 does not allow synchronization of devices 10, whose clock is clocked at megahertz, at a time scale of the order of one microsecond. In other words, the drift of the clocks of the devices 10 would be problematic if the devices 10 were to be fully synchronized by this means.
• the Applicant has determined that it remains possible to asynchronously coordinate the devices 10 at a time scale greater than that of their own operation. It was then necessary to design the control units 12 of the devices 10 so as to allow centralized control at the pilot level 8 of the distributed units constituted by the devices 10, while ensuring a temporal decoupling between the synchronization within each device 10 and synchronization between the devices 10.
• each control unit 12 receives and executes instructions in the form of microprograms which translate a stimulation profile of the type shown in FIG. 5.
• microprograms are themselves ordered within of the device 10, in the form of a sequence of the type of that shown in FIG.
• a microprogram can translate for example an impedance measurement, and a sequence can therefore contain an ordered sequence of measurements and stimulations.
• the operating architecture of the control unit 12 is as follows:
• a sequencer 46 receives via the interface 40 requests from the driver 8, which are optionally accompanied by data.
• the optional data correspond either to microprograms or to multipolar configurations of the electrodes connected to the unit 12, or to the contents of the sequence implemented by the sequencer. All these elements are described later.
• the requests received by the sequencer 46 correspond either to control commands (execute, stop, etc.) or to programming commands of the sequencer 46 (write the optional data and / or read data).
• the sequencer 46 stores the data received in the storage elements as described below.
• the sequencer 46 triggers, on request, the execution of microprograms on multipolar configurations. For this, it indicates to an executor 48, which is in the example described here a specific microcontroller ASIP type (Application Specifies Instruction Set Processor or Processor Application Specific Set of Instructions), the firmware to be executed, and
• the microcontroller 48 executes the sequence of instructions contained in the microprograite indicated by the sequencer and consequently drives the digital / analog converter 42 which is connected to the electrodes.
• the microcontroller 48 also provides the desired multipolar configuration on the corresponding electrodes.
• a sequence defines an interval-divided time window, within which are designated pacing programs to be executed on associated multipole configurations in the intervals.
• the intervals can be set in number and duration.
• control unit 12 comprises a memory 50 for storing the microprograms.
• the memory 50 stores 8 separate firmware.
• the memory 50 comprises data that combine on the one hand a firmware identifier, and on the other hand firmware data.
• the firmware data is a sequence of instructions consisting of 24-bit words in the example described here, which correspond to various stimulation profiles.
• a stimulation profile describes the shape of the stimulus to be applied, with the different phases of charging and discharging.
• Table 1 in Appendix A represents a set of possible instructions for these words.
• Table 2 shows a firmware that encodes the stimulation profile shown in Figure 5, where the ordinate axis refers to the intensity of the stimulation and the x-axis refers to the time elapsed from the beginning of the interval.
• Table 3 shows another example of firmware whose active phase is trapezoidal.
• modulation register data there is the presence of modulation register data. These registers are very advantageous. Indeed, the sequencer 46 maintains in the temporary memory 54 three modulation registers for the intensity I, and three modulation registers for the duration T. More precisely, when the sequencer receives modulation data, it writes them directly in the concerned registers. When an instruction is executed and includes one or more references to addresses of these registers, the executor 48 takes into account in its execution.
• control unit 12 comprises a memory 52 for storing the multipole configurations of the electrodes 14. More specifically, each configuration indicates the poles of an electrode that are used.
• the memory 52 stores 8 separate electrode configurations per managed electrode.
• the memory 52 comprises data that combine on the one hand an electrode configuration identifier, and on the other hand electrode configuration data.
• the electrode configuration data are formed by a 72-bit word comprising configuration subwords and ratio sub-words (current distribution between the active poles). Each sub-word of configuration comes to specify which pole is active and with what polarity, and each sub-word of ratio comes to specify for each active pole what is the quantity of current of the pulse which it will receive.
• the configuration of the electrode consists in defining how the current profile defined by the microprogram will be distributed over all the poles of the electrode.
• Polarity X can be coded on 1 bit (0 for anode and 1 for cathode), state Y can be coded on 1 bit (0 for high impedance and 1 for active), and the current ratio Z can be coded on 4 bits (or sixteen fractions of 0.0625 for each bit).
• the configuration word is a sequence of 12 words of the XYZ type.
• the set XY constitutes for each pole the subword of configuration, and Z constitutes the subword of ratio, for example coded on 4 bits.
• a conventional three-pole electrode a cathode ring in the center and 2 anodes outside
• the data stored in the memory 52 is reconfigurable. Indeed, although the indices of the memory 52 each absolutely refer to a precise pole of an electrode, the driver 8 can send a request to redefine these indices.
• the indices of the memory 52 could be relative, that is to say that they could designate each pole with respect to a reference pole of the configuration.
• the control unit 12 could reconfigure the electrode in case of displacement thereof.
• the sequencer When the sequencer receives a command triplet, it stores in the temporary memory 54 the corresponding microprogram and electrode configuration.
• Fig. 6 shows an example of a slot window in memory 54.
• the sequencer 46 receives a sequence execution command, it controls the microcontroller 48 according to the contents of the memory 54.
• the control unit 12 manages several electrodes, the memories 50, 52 and 54 receive identifiers specific to each electrode, and the triplets are adapted accordingly.
• the device 10 is designed to be controlled completely remotely by the driver 8, with optimized power consumption and minimal data exchange between system elements. For security reasons, it is possible to reserve the last interval for passive discharge. Moreover, this last interval being of modifiable duration, it then makes it possible to finely adjust the frequency of repetitions of the stimulations.
• FIGS. 7 and 8 will show the architecture of the pilot 8 and the management by the latter of the synchronization of the different devices 10.
• the driver 8 comprises two communication interfaces 70 and 71, a clock 72, a controller 74, and memories 76, 78 and 80.
• the communication interface 70 is connected to the bus 11 to transmit the commands to the various devices 10.
• the interface 71 provides wireless communication of the system with the external control 6, for example by an inductive link or by an RF link.
• the Clock 72 operates at about 12 MHz and provides coordinated exercise of the various functions.
• the operating frequency of the clock may vary according to the amount of information that the controller 74 must communicate to the devices 10. The latter must deal with "logical" instructions, that is to say, high level and the higher the speed of the clock must be important.
• the operation of the controller 74 will be explained with FIG.
• the memory 76 stores data that combine, on the one hand, a motor function identifier and, on the other hand, motor function data.
• the driving function data includes sequentially and / or parallel sequences of triplets (slot reference in the window; electrode configuration identifier; firmware identifier) each designating an electrode of one (or more) devices. (s) 10 given.
• triplet described here is not limiting. Indeed, the interval reference data in the window could be implicit. Triplets must therefore be considered as ordered pairs, the order of the pairs being explicit or implicit.
• the anodal blocking may require a specific profile whose execution generates at least two contiguous stimulation slots on an electrode set consisting of a central cathode and one or two possibly asymmetrical external anodes. This allows for example to control separately the contraction of the striated sphincter of the urethra and the smooth muscle of the bladder (the Detrusor) innervated by the same set of nerves ensuring a more natural urination.
• Another example is to sequence several triplets to get the stimulation of several muscles.
• the sequencer manages at the same time several windows made up of intervals.
• the windows are then of identical characteristics, that is to say with the same number of intervals and the same durations).
• sequencer and the executor may have a similar architecture, that is to say that if the sequencer admits of parallelism, then it will be advantageous for the executor too.
• the sequencer and the executor function in pairs according to a technique in which the sequencer determines the set of deadlines from the intervals in parallel at the instant considered, and it controls the executor according to these deadlines. If the sequencer does not allow parallelism, then it is better that the executor either. The sequencer then controls the executor by asking him to activate the firmware at the instant in question.
• sequencer can set up the multipolar configuration before launching the executor, that is writing in the registers of the analog stage, during the time available between the end of the programmed activity. in a current interval and activating a next interval.
• the memory 78 is a temporary memory which stores the "current" state of each window and of each of the electrodes of the devices 10.
• the driver 8 since the driver 8 knows which microprograms it has sent to which electrodes with their corresponding electrode configurations, it can store in the memory 78 a representation of the state of these for the coordination purposes discussed above.
• the memory 78 also stores the current state of operation of the stimulation system 2, that is to say the function or functions currently implemented, and a queue of functions to implement.
• the queue is used to organize the orderly execution of scheduled functions on the one hand and point functions on the other.
• Plant functions means the functions that are generally performed by the practitioner and that are performed on a permanent basis, for example the anti-cancer function, anti-hyperflexia, anti-pain function, etc.
• point function we mean the functions solicited by the patient at a given moment, for example urination.
• the memory 78 thus allows a scheduling of the execution of these functions.
• the memory 80 is a configuration memory, which stores all the memories 50 and 52 of each of the control units 12 of the devices 10. Thus, the driver 8 has a total view of the possible stimulations by the devices 10.
• the memory 80 may be used to reconfigure certain devices 10. In fact, there is provided a specific synchronization command between the memory 80 and the memories 50 and 52 of the devices 10. Figure 8 will now be described to explain the operation of the controller 74.
• the operation of the controller 74 can be seen as a continuously repeated loop.
• the controller 74 receives a command to execute a function sent by the external command 6 or a planned function, a set of operations is started.
• FIG. 8 starts at 800 from the receipt of a function command from the external control 6.
• the controller 74 calls the memory 76 with a function identifier derived from the operation 800, and retrieves the data relating to the realization of this function.
• the controller 74 determines by means of a function Compatf) if this function command can be executed immediately.
• the Compat () function can be based on the call of the memory 78 to check which electrodes are stimulated at this time, and on the compatibility data call of this function with the functions currently implemented.
• the conditions determining the authorization or the prohibition of the execution of certain functions can be dynamic.
• constraints of a technical nature such as the available energy, or the failure of a subsystem, which in the absence of a backup solution, may require the prohibition of the launching of a function, or even the interruption of a function. running a function in progress.
• this function is commanded in an operation 830, that is to say that the triplets defining it are transmitted in the order required for the various devices. 10, where these triplets are simply activated if they have already been transmitted and stored in the memory 54 of the devices 12 involved in this function.
• an Except () function is called in an 840 operation.
• the Except () function has the role of determining if the execution of the command received in 800 poses a major problem, which makes it incompatible with the existing queue. , or not. If this is the case, then a message indicating this impossibility of execution is sent to the external command 6 for communication to the person. Otherwise, the function is placed in the queue of the memory 78. Finally, the operation is displayed in 850.
• the implementation of various elements of this description, in particular the different parts of the stimulation unit 12 or the controller 8, can be implemented on components such as microcontrollers, microprocessors or signal processors (DSP).
• DSP signal processors

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• 2010
  • 2010-04-16 FR FR1001625A patent/FR2958857B1/fr active Active
• 2011
  • 2011-04-15 WO PCT/FR2011/050869 patent/WO2011128601A1/fr active Application Filing
  • 2011-04-15 EP EP11719598A patent/EP2558157A1/de not_active Ceased
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