Method and apparatus for communicating with implanted body function stimulator

• US 4,539,992 A
• Filed: 04/25/1983
• Issued: 09/10/1985
• Est. Priority Date: 12/22/1978
• Status: Expired due to Term

• Current Assignee: Intermedics Incorporated
• Original Assignee: Intermedics Incorporated
• Inventors: Baker, Ross G. Jr., Calfee, Richard V., Gordon, Pat L., Terry, Reese S. Jr., Bertasz, Robert N.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/486,157
• Time in Patent Office: 869 Days
• Field of Search: 128/419 PG, 128/903, 128/419 E
• US Class Current: 607/32
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique

Abstract

An external command device and an internal decoding and verification device are used to non-invasively alter the operating parameters of a programmable device implanted in an animal body. Thus, physiological changes can be easily accommodated by the implanted device. In a preferred embodiment, pulse position modulation is used to externally encode the command information. A resulting string of current pulses generates voltage spikes (in the internal decoding device) through inductively coupled coils. Each incoming data bit is verified and the entire command word is verified. After verification, the decoded command is transferred to a command register for simultaneously altering the selected operating parameters. The internal receiver circuitry may conveniently utilize energy from the induced voltage spike, using passive components for forming an output suitable for processing.

Claims

1. In a method for varying the operating parameters of a body implantable device by non-invasively coupling an externally generated control signal to electronic circuitry within said implantable device and deriving a binary control word for varying said parameters, an improved method for preventing inadvertent variation of said operating parameters, comprising the steps of:

deriving a first binary word functionally equivalent to a first externally generated control signal,

deriving a second binary word functionally equivalent to a second externally generated control signal,

said first and second externally generated control signals each functionally related to a same set of selected operating parameters,

serially comparing said first and second binary words to verify equivalence, and

thereafter transferring said verified binary control word to a command register for altering said operating parameters.

2. The method according to claim 1, wherein comparing said first and second binary words to verify equivalence further comprises the steps of:

storing said first binary word in a first serial register,

serially comparing said first binary word and said second binary word, and

storing said second binary word in said first serial register.

3. The method according to claim 2, wherein said first binary word is serially output from said first register as said second binary word is serially input to said first register.

4. The method according to claims 1 or 2, including the step of:

deriving said second binary word as the complement of said first binary word.

5. In apparatus for varying the operating parameters of a body implantable device by non-invasively coupling an externally generated control signal to electronic circuitry within said device and deriving a binary control word for varying said operating parameters, improved apparatus for preventing inadvertent variation of said operating parameters, comprising:

means for deriving a first binary word functionally equivalent to a first externally generated control signal,

means for deriving a second binary word functionally equivalent to a second externally generated control signal,

said first and second externally generated control signals each functionally related to a same set of selected operating parameters,

means for serially comparing said first and second binary words to verify equivalence, and

electronic circuitry for transferring said verified binary control word to a command register for altering said operating parameters.

6. Apparatus according to claim 5, wherein said means for comparing said first and second binary words to verify equivalence further comprises:

a first serial register for storing said first binary word,

means for serially comparing said first binary word and said second binary word, and

a second serial register for storing said verified binary control word.

7. Apparatus according to claim 6, including means for serially removing said first binary word from said first register as said second binary word is serially input to said second register.

8. Apparatus according to claims 6 or 7, wherein said first register and said second register comprise a single register.

9. Apparatus according to claims 5 or 6, including:

means for deriving said second binary word as the complement of said first binary word.

10. Apparatus for commanding a body function stimulating device adapted for body implantation, comprising:

means for generating an electrical command signal functionally related to selected operating parameters for said stimulating device;

means for converting said electrical command signal to an equivalent train of current pulse pairs having first or second temporal relationships and each pulse having at least one sharp edge shape;

a first coil means responsive to said current pulse pairs generating magnetic fields having a peak rate of change of intensity defined by said at least sharp edge shape of each said pulse;

a second coil means electrically connected to said stimulating device detecting at least said peak rate of change of intensity portions of said magnetic fields and producing corresponding pairs of voltage output pulses having said first or second temporal relationship;

means for processing said pairs of voltage output pulses to reproduce said electrical command signal within said stimulating device.

11. Apparatus according to claim 10, wherein said means for processing said pairs of voltage output pulses comprises:

means for generating single pulses from said pairs of voltage pulses having first and second durations corresponding to said first and second temporal relationships, respectively.

12. Apparatus according to claim 11, comprising:

means for gating each of said single pulses at first preselected intervals, and

means for generating a data signal having a binary output determined by the output level of said single pulse during said gating at said first interval.

13. Apparatus according to claim 12, further comprising:

means for detecting the level of said single pulses at second preselected intervals to verify the absence of anomalies in said single pulse.

14. Apparatus according to one of claims 10, 11, 12, or 13, wherein

said first temporal relationship represents a first binary state and said second temporal relationship represents a second binary state.

15. Apparatus according to one of claims 10, 11, 12, or 13, further including:

means for generating first and second portions of said electrical command signal functionally related to said selected operating parameters,

means for decoding said first portion of said electrical command signal and generating a corresponding first binary word within said stimulating device,

means for decoding said second portion of said electrical command signal and generating a corresponding second binary word within said stimulating device; and

means for serially comparing said second binary word with said first binary word and upon determining the equivalence of the binary words applying one of the words to set said selected operating parameters for the stimulating device.

16. Apparatus according to claim 15, including:

means for generating said second portion of said electrical command signal as functionally equivalent to a binary complement of said first portion of said electrical command signal.

17. A method for commanding a body function stimulating device adapted for body implanatation, comprising the steps of:

generating an electrical command signal functionally related to selected operating parameters for said stimulating device;

converting said electrical command signal to an equivalent train of current pulse pairs having first or second temporal relationships and each pulse having at least one sharp edge shape;

generating magnetic fields in response to said current pulse pairs having a peak rate of change of intensity defined by said at least one sharp edge shape of each said pulse;

detecting within said stimulating device at least said peak rate of change of intensity portions of said magnetic fields and producing corresponding pairs of voltage output pulses having said first or second temporal relationship;

processing said pairs of voltage output pulses to reproduce said electrical command signal within said stimulating device.

18. A method according to claim 17, wherein processing said pairs of voltage output pulses comprises:

generating single pulses from said pairs of pulses having first and second durations corresponding to said first and second temporal relationships, repsectively.

19. A method according to claim 18, comprising:

gating each of said single pulses at first preselected intervals, and

generating a data signal having a binary output determined by the output level of said single pulse during said gating at said first interval.

20. A method according to claim 19, further comprising:

detecting the level of said single pulses at second preselected intervals to verify the absence of anomalies in said single pulses.

21. A method according to one of claim 17, 18, 19, or 20, wherein:

said first temporal relationship represents a first binary state and said second temporal relationship represents a second binary state.

22. A method according to one of claims 17, 18, 19, or 20, further including the steps of:

generating first and second portions of said electrical command signal functionally related to selected operating parameters,

decoding said first and second portions and repsectively generating corresponding first and second binary words within said stimulating device, and serially comparing said first binary word and said second binary word and setting said selected operating parameters upon determining the equivalence of the words.

23. A method according to claim 22, including:

generating said second portion of said electrical command signal as functionally equivalent to a binary complement of said first portion of said electrical command signal.

24. In apparatus for varying the operating parameters of a body function stimulating device adapted for body implantation by non-invasively coupling an externally generated control signal to electronic circuitry within said implantable device and deriving a control signal for varying said parameters, improved apparatus for transmitting said control signal, comprising:

means for generating an electrical command signal functionally related to selected operating parameters for said stimulating device;

means for converting said electrical command signal to an equivalent train of current pulse pairs having first or second temporal relationships, said first temporal relationship corresponding to a first binary state and said second temporal relationship corresponding to a second binary state;

means for generating an output functionally related to said pulse pairs;

means for detecting said output and producing corresponding pairs of voltage output pulses having said first and second temporal relationship; and

means for processing said pairs of voltage output pulses to reproduce said electrical command signal within said stimulating device.

25. Apparatus according to claim 24, wherein said means for processing said pairs of voltage output pulses comprises:

means for generating single pulses from said pairs of voltage pulses having first and second durations corresponding to said first and second temporal relationships, respectively.

26. Apparatus according to claim 25, comprising:

means for gating each of said single pulses at first preselected intervals, and

means for generating a data signal having a binary output determined by the output level of said single pulse during said gating at said first interval.

27. Apparatus according to claim 26, further comprising:

means for detecting the level of said single pulses at second preselected intervals to verify the absence of anomalies in said single pulses.

28. In a method for varying the operating parameters of a body function stimulating device adapted for body implantation by non-invasively coupling an externally generated control signal to electronic circuitry within said implantable device and deriving a control signal for varying said parameters, an improved method for generating said command signal, comprising the steps of:

generating an electrical command signal functionally related to selected operating parameters for said stimulating device;

converting said electrical command signal to an equivalent train of current pulse pairs having first or second temporal relationships, said first temporal relationship corresponding to a first binary state and said second temporal relationship corresponding to a second binary state;

generating an output functionally related to said pulse pairs;

detecting said output;

producing corresponding pairs of voltage output pulses having said first or second temporal relationship; and

processing said pairs of voltage output pulses to reproduce said electrical command signal within said stimulating device.

29. A method according to claim 28, wherein said means for processing said pairs of voltage output pulses comprises:

generating single pulses from said pairs of pulses having first and second durations corresponding to said first and second temporal relationships, repsectively.

30. A method according to claim 29, comprising:

gating each of said single pusles at first preselected intervals, and

generating a data signal having a binary output determined by the output level of said single pulse during said gating at said first interval.

31. A method according to claim 30, further comprising:

detecting the level of said single pulses at second preselected intervals to verify the absence of anomalies in said single pulses.

32. A system for communicating parameter control information from a control device to a body implantable device, comprising:

select means of said control device for defining parameter control information;

coding means of said control device for generating binary coded pulse position modulated signals representative of said defined parameter control information; and

transmitter means of said control device for transmitting said binary coded pulse position modulated signals to said body implantable device;

receiving means of said body implantable device for receiving said binary coded pulse position modulated signals and decoding said signals to derive said parameter control information, and operating means of said body implantable device for applying said derived parameter control information to operate the device.

33. The system of claim 32, wherein said transmitter means includes a transmitter coil;

and said coding means includes;

means for defining an output parameter code word having a plurality of binary bits representative of said defined parameter control information; and

means for producing and applying current pulses to said transmitter coil, said current pulses having edges spaced at intervals representative of said binary bits of said output parameter code word so that the transmitter coil transmits electromagnetic pulses spaced with corresponding intervals.

34. The system of claim 33, wherein said receiving means includes:

receiving coil means for generating voltage pulses at intervals corresponding to the intervals of said electromagnetic pulses;

decoding means for generating synchronized signals with pulse widths corresponding to the intervals between the voltage pulses; and

sampling means for generating an input parameter code word having binary bits representative of the pulse widths of the synchronized signals and corresponding to the bits of the output parameter code word,

said operating means including means for applying the input parameter code word to control said implantable device.

35. The apparatus of claim 34, wherein said sampling means includes means for checking predefined portions of said synchronized signals to determine whether the signals have electrical anomalies.

36. The apparatus of claim 34, wherein said means for defining includes means for generating an output parameter check word with binary bits which are the complement of the bits of said output parameter code word, said means for producing and applying current pulses including means for applying edges of current pulses to said transmitter coil at intervals representative of the binary bits of the parameter check word, so that the transmitter coil transmits electromagnetic pulses spaced at corresponding intervals,

said sampling means including means for generating an input parameter check word having bits corresponding to the bits of the output parameter check word, and means for comparing the input parameter code word and input parameter check word to determine if they match as complements, said means for applying control data including means for applying the input parameter code word to control the implantable device in the event of a match.

37. A system for communicating parameter control information to a body stimulation device implanted in the body, comprising:

transmitter means outside the body for transmitting binary coded pulse position modulated electromagnetic signals representative of selected parameter control information;

means of said body stimulation device for receiving said electromagnetic signals and decoding the signals to derive at least one binary coded word representative of said selected parameter control information;

means of said body stimulation device for verifying the validity of said at least one binary word; and

means of said body stimulation device for applying the verified binary coded word to set at least one operating parameter of the body stimulation device.

38. The system of claim 37, wherein said transmitter means includes means for transmitting electromagnetic signals representative of said binary coded word and its binary complement,

said means for receiving including means for decoding the electromagnetic signals to derive said binary coded word and its binary complement, and

said means for verifying includes means for comparing the binary coded word and its binary complement.

39. The system of claim 37, wherein said means for verifying includes means for checking predefined signal portions of said at least one binary coded word to verify that the signal portions have no electrical anomalies.

40. A system for communicating selected parameter control information from a control device to a body implatable device, comprising:

transmitter means of said control device for generating electromagnetic pulses spaced at intervals representative of binary bits which define said selected parameter control information;

receiving means of said body implantable device for detecting said electromagnetic pulses and generating derived pulses having widths corresponding to the intervals between the electromagnetic pulses;

means of said body implantable device for converting the pulse widths of the derived pulses to binary logic signals representative of said selected parameter control information; and

means of said body implantable device for applying the binary logic signals to control selected parameters of the implantable device.

41. A system for communicating selected parameter control information from a control device to a body implantable device, comprising:

coding means of said control device for generating current pulses having edges spaced at intervals representative of selected parameter control information;

and transmitting coil means of said control device for transmitting an output signal for each of the spaced edges of said current pulses,

said body implantable device including,

receiving coil means for detecting each of said output signals and generating a corresponding input signal,

means for decoding the intervals between input signals to derive control signals representative of said selected parameter control information, and

means for applying said control signals to control the operation of said implantable device.

42. A system for communicating selected parameter control information from a control device to a body implantable device, comprising:

coding means of said control device for generating signals having trailing edges spaced at intervals representative of said selected parameter control information;

a transmitter coil of said control device for transmitting an electromagnetic pulse for each of said trailing edges;

a receiver coil of said control device for sensing said electromagnetic pulses and generating corresponding voltage pulses; and

means of said body implantable device responsive to the intervals between said voltage pulses for deriving the selected parameter control information and applying the information to control the implantable device.

43. A body implantable device, comprising:

means for receiving binary coded pulse position modulated signals representative of parameter control information;

means for decoding said binary coded pulse position modulated signals to derive said parameter control information; and

means for applying said parameter control information to set operating parameters of said body implantable device.