Method and apparatus to limit control of parameters of electrical tissue stimulators

• US 5,443,486 A
• Filed: 09/26/1994
• Issued: 08/22/1995
• Est. Priority Date: 09/26/1994
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hrdlicka, Gregory A., Thompson, David L.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US08/312,340
• Time in Patent Office: 330 Days
• Field of Search: 607/30, 607/2, 607/46, 607/62, 607/63, 607/72, 607/148, 607/117, 607/59, 607/60
• US Class Current: 607/59
• CPC Class Codes: A61N 1/36021 for treatment of pain
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36146 specified by the stimulation parameters
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: A61N 1/37254 Pacemaker or defibrillator security, e.g. to prevent or inhibit programming alterations by hackers or unauthorised individuals

Abstract

Electrical tissue stimulator and method for limiting the programmability of stimulation pulse parameters. The tissue stimulator includes a plurality of electrodes and a memory for holding a stimulation pulse parameter limit value and a programmed parameter value of a stimulation pulse. A pulse generator applies electrical stimulation pulses to the electrodes in accordance with the programmed parameter value. Programming means is included for receiving remotely generated programming signals and altering the contents of the memory in accordance with the signals. Means is included for comparing the stimulation pulse parameter limit value and the programmed parameter value and for preventing an alteration of the programmed parameter value, unless it is within stimulation pulse parameter limits. The stimulation pulse parameters may include pulse amplitude, pulse width, and pulse rate and the programmed parameter limit values may be upper and lower limits.

Claims

1. An electrical tissue stimulator comprising:

a plurality of electrodes to be implanted in a patient;

a first memory for holding a stimulation pulse parameter limit value of a stimulation pulse;

a second memory for holding a programmed parameter value of a stimulation pulse;

a pulse generator for applying electrical stimulation pulses to said electrodes in accordance with said programmed parameter value;

programming means for receiving remotely generated programming signals and altering the contents of at least one of said first and second memories in accordance with said signals; and

means for comparing said stimulation pulse parameter limit value and said programmed parameter value and for preventing said programming means from increasing said programmed parameter value unless said programmed parameter value is less than said stimulation pulse parameter limit value.

2. A tissue stimulator according to claim 1 wherein said programming means includes a means to detect remotely generated programmed parameter value increase signals, said programming means being responsive to increase said programmed parameter value upon receipt of said increase signals.

3. A tissue stimulator according to claim 1 wherein the stimulation pulse parameter limit value contained in said first memory is an upper pulse parameter limit value and wherein the stimulator further comprises a third memory for holding a lower pulse parameter limit value, the contents of said third memory being alterable by said programming means in accordance with remotely generated programming signals, and wherein said comparing means compares said upper pulse parameter limit value, said programmed parameter value and said lower pulse parameter limit value and prevents said programming means form increasing said programmed parameter value unless said programmed parameter value is less than said upper pulse parameter limit value and from decreasing said programmed parameter value unless said programmed parameter value is greater that said lower pulse parameter limit value.

4. A tissue stimulator according to claim 3 wherein said programming signals are digital signals.

5. A tissue stimulator according to claim 3 wherein said programming means includes a means to detect remotely generated programmed parameter value increase signals and programmed parameter value decrease signals, said programming means being responsive to increase said programmed parameter value upon receipt of said increase signals and to decrease said programmed parameter value upon receipt of said decrease signals and wherein said comparing means includes means to compare said programmed parameter value to said upper pulse parameter limit value and to said lower pulse parameter limit value and to prevent said programming means from increasing said programmed parameter value unless said programmed parameter value is less than said upper pulse parameter limit and from decreasing said programmed parameter value unless said programmed parameter value is greater than said lower pulse parameter limit value.

6. An electrical tissue stimulator according to claim 1 wherein said stimulation pulse parameter limit value is one of stimulation pulse amplitude limit value, stimulation pulse rate limit value and stimulation pulse width limit value.

7. An electrical tissue stimulator comprising:

a plurality of electrodes to be implanted in a patient;

a first memory for holding a stimulation pulse parameter limit value of a stimulation pulse;

a second memory for holding a programmed parameter value of said stimulation pulse;

a pulse generator for applying electrical stimulation pulses to said electrodes in accordance with said programmed parameter value;

programming means for receiving remotely generated programming signals and altering the contents of at least one of said first and second memories in accordance with said signals to permit said stimulation pulse parameter limit value and said programmed parameter value to be remotely programmed; and

means for comparing said stimulation pulse parameter limit value and said programmed parameter value and for preventing said programming means from decreasing said programmed parameter value unless said programmed parameter value is greater than said stimulation pulse parameter limit value.

8. A tissue stimulator according to claim 7 wherein said programming means includes a means to detect remotely generated programmed parameter value decrease signals, said programming means being responsive to decrease said programmed parameter value upon receipt of said decrease signals, and wherein said comparing means includes means to compare said programmed parameter value to said stimulation pulse parameter limit value and to prevent said programming means from decreasing said programmed parameter value unless said programmed parameter value is greater than said stimulation pulse parameter limit value.

9. An electrical tissue stimulator according to claim 7 wherein said stimulation pulse parameter limit value is one of stimulation pulse amplitude limit value, stimulation pulse rate limit value and stimulation pulse width limit value.

10. An electrical tissue stimulator comprising:

a plurality of electrodes to be implanted in a patient;

a first memory for holding a first stimulation pulse parameter limit value of a stimulation pulse and a first programmed parameter value of said stimulation pulse;

a pulse generator for applying electrical stimulation pulses to said electrodes in accordance with said first programmed parameter value;

programming means for receiving remotely generated programming signals and altering the contents of said first memory in accordance with said signals to permit said first parameter limit value and said first programmed parameter value to be remotely programmed; and

means for comparing said first parameter limit value and said first programmed parameter value and for preventing said programming means from increasing said first programmed parameter value unless said first programmed parameter value is less than said first parameter limit value.

11. An electrical tissue stimulator according to claim 10 further comprising a second memory for holding a second stimulation pulse parameter limit value of a stimulation pulse and a second programmed parameter value of said stimulation pulse, and wherein said pulse generator applies stimulation pulses to said electrodes in accordance with said first and second programmed parameter values, the contents of said second memory being alterable by said programming means in accordance with said remotely generated programming signals, and wherein said means for comparing compares said second parameter limit value and said second programmed parameter value and prevents said programming means form increasing said second programmed parameter value unless said second programmed parameter value is less than said second parameter limit value.

12. An electrical tissue stimulator according to claim 11 further comprising a third memory for holding a third stimulation pulse parameter limit value of a stimulation pulse and a third programmed parameter value of said stimulation pulse, and wherein said pulse generator applies stimulation pulses to said electrodes in accordance with said first, second and third programmed parameter values, the contents of said third memory being alterable by said programming means in accordance with said remotely generated programming signals, and wherein said means for comparing compares said third parameter limit value and said third programmed parameter value and prevents said programming means from increasing said third programmed parameter value unless said third programmed parameter value is less than said third parameter limit value.

13. An electrical tissue stimulator according to claim 12 wherein the first, second and third stimulation pulse parameter limit values contained in said first, second and third memories each comprise an upper pulse parameter limit value and a lower pulse parameter limit value, and wherein said comparing means compares said first parameter limit value to said first programmed parameter value, said second parameter limit value to said second programmed parameter value and said third parameter limit value to said third programmed parameter value and prevents said programming means from increasing the value of said first programmed parameter value unless said first programmed parameter value is less than said upper parameter limit value and from decreasing the value of said first programmed parameter value unless said first programmed parameter value is greater than said lower parameter limit value of said first stimulation pulse parameter limit value, from increasing the value of said second programmed parameter value unless said second programmed parameter value is less than said upper parameter limit value and from decreasing the value of said second programmed parameter value unless said second programmed parameter value is greater than said lower parameter limit value of said second stimulation pulse parameter limit value, and from increasing the value of said third programmed parameter value unless said third programmed parameter value is less than said upper parameter limit value and from decreasing the value of said third programmed parameter value unless said third programmed parameter value is greater than said lower parameter limit value of said third stimulation pulse parameter limit value.

14. A tissue stimulator according to claim 13 wherein said programming means includes a means to detect remotely generated first, second and third programmed parameter value increase signals and first, second and third programmed parameter value decrease signals, said programming means being responsive to increase said first programmed parameter value upon receipt of said first programmed parameter increase signals and to decrease said first programmed parameter value upon receipt of said first programmed parameter decrease signals, said programming means being further responsive to increase said second programmed parameter value upon receipt of said second programmed parameter increase signals and to decrease said second programmed parameter value upon receipt of said second programmed parameter decrease signals, said programming means being further responsive to increase said third programmed parameter value upon receipt of said third programmed parameter increase signals and to decrease said third programmed parameter value upon receipt of said third programmed parameter decrease signals.

15. A tissue stimulator according to claim 12 wherein said programming means includes means to detect remotely generated first, second and third programmed parameter value increase signals, said programming means being responsive to increase said first programmed parameter value upon receipt of said first programmed parameter increase signals, to increase said second programmed parameter value upon receipt of said second programmed parameter increase signals, and to increase said third parameter value upon receipt of said third parameter value increase signals.

16. An electrical tissue stimulator according to claim 11 wherein said first and second stimulation pulse parameter limit values contained in said first and second memories each comprise an upper pulse parameter limit value and a lower pulse parameter limit value, and wherein said comparing means compares said first parameter limit value to said first programmed parameter value and said second parameter limit value to said second programmed parameter value and prevents said programming means from increasing the value of said first programmed parameter value unless said first programmed parameter value is less than said upper parameter limit value and from decreasing the value of said first programmed parameter value unless said first programmed parameter value is greater than said lower parameter limit value of said first stimulation pulse parameter limit value and further prevents said programming means from increasing the value of said second programmed parameter value unless said second programmed parameter value is less than said upper parameter limit value and from decreasing the value of said second programmed parameter value unless said second programmed parameter value is greater than said lower parameter limit value of said second stimulation pulse parameter limit value.

17. A tissue stimulator according to claim 16 wherein said programming means includes a means to detect remotely generated first and second programmed parameter value increase signals and first and second programmed parameter value decrease signals, said programming means being responsive to increase said first programmed parameter value upon receipt of said first programmed parameter increase signals and to decrease said first programmed parameter value upon receipt of said first programmed parameter decrease signals, said programming means being further responsive to increase said second programmed parameter value upon receipt of said second programmed parameter increase signals and to decrease said second programmed parameter value upon receipt of said second programmed parameter decrease signals.

18. A tissue stimulator according to claim 11 wherein said programming means includes means to detect remotely generated first and second programmed parameter value increase signals, said programming means being responsive to increase said first programmed parameter value upon receipt of said first programmed parameter increase signals, said programming means being further responsive to increase said second programmed parameter value upon receipt of said second programmed parameter increase signals.

19. An electrical tissue stimulator according to claim 10 wherein said first stimulation pulse parameter limit value contained in said first memory comprises an upper pulse parameter limit value and a lower pulse parameter limit value and wherein said comparing means compares said upper pulse parameter limit value, said first programmed parameter value and said lower pulse parameter limit value and prevents said programming means from increasing said first programmed parameter value unless said first programmed value is less than said upper parameter limit value and from decreasing the value of said first programmed parameter value unless said first programmed parameter value is greater than said lower parameter limit value.

20. A tissue stimulator according to claim 19 wherein said programming means includes a means to detect remotely generated first programmed parameter value increase signals and first programmed parameter value decrease signals, said programming means being responsive to increase said first programmed parameter value upon receipt of said first programmed parameter increase signals and to decrease said first programmed parameter value upon receipt of said first programmed parameter decrease signals.

21. A tissue stimulator according to claim 10 wherein said programming means includes a means to detect remotely generated programmed parameter value increase signals, said programming means being responsive to increase said first programmed parameter value upon receipt of said increase signals.

22. An electrical tissue stimulator comprising:

a plurality of electrodes to be implanted in a patient;

a pulse rate memory for holding upper and lower stimulation pulse rate limit values of a stimulation pulse and a first programmed pulse rate value of said stimulation pulse;

a pulse width memory for holding upper and lower stimulation pulse width limit values of a stimulation pulse and a first programmed pulse width value of said stimulation pulse;

a pulse amplitude memory for holding upper and lower stimulation pulse amplitude limit values of a stimulation pulse and a first programmed pulse amplitude value of said stimulation pulse;

a pulse generator for applying electrical stimulation pulses to said electrodes in accordance with said first programmed pulse rate, pulse width and pulse amplitude values;

programming means for receiving remotely generated programming signals and altering the contents of at least one of said pulse rate, pulse width and pulse amplitude memories in accordance with said signals to permit said pulse rate, pulse width and pulse amplitude upper and lower limit values and said first programmed pulse rate, pulse width and pulse amplitude values to be remotely programmed; and

means for comparing said pulse rate, pulse width and pulse amplitude upper and lower limit values with said first programmed pulse rate, pulse width and pulse amplitude values and for preventing said programming means from increasing said first programmed pulse rate value unless said programmed pulse rate value is less than said upper stimulation pulse rate limit value and from decreasing said first programmed pulse rate value unless said programmed pulse rate value is greater than said lower stimulation pulse rate limit value, for preventing said programming means from increasing said first programmed pulse width value unless said first programmed pulse width value is less than said upper stimulation pulse width limit value and from decreasing said first programmed pulse width value unless said first programmed pulse width value is greater than said lower stimulation pulse width limit value, and for preventing said programming means from increasing said first programmed pulse amplitude value unless said first programmed pulse amplitude value is less than said upper stimulation pulse amplitude limit value and from decreasing said first programmed pulse amplitude value unless said first programmed pulse amplitude value is greater than said lower stimulation pulse amplitude limit value.

23. A tissue stimulator according to claim 22 wherein said programming means includes a means to detect remotely generated pulse rate, pulse width and pulse amplitude value increase and decrease signals, said programming means being responsive to increase said first programmed pulse rate value upon receipt of said pulse rate increase signals and to decrease said first programmed pulse rate value upon receipt of said pulse rate decrease signals, said programming means being further responsive to increase said first programmed pulse width value upon receipt of said pulse width increase signals and to decrease said first programmed pulse width value upon receipt of said pulse width decrease signals, said programming means being further responsive to increase said first programmed pulse amplitude value upon receipt of said pulse amplitude increase signals and to decrease said first programmed pulse amplitude value upon receipt of said pulse amplitude decrease signals.

24. A method of limiting the programmability of a stimulation pulse parameter of an implantable tissue stimulator comprising:

programming a first memory with a stimulation pulse parameter limit value;

programming a second memory with a stimulation pulse parameter value;

receiving remotely generated programming signals;

altering the contents of at least one of said first and second memories in accordance with said programming signals;

comparing said stimulation pulse parameter limit value and said stimulation pulse parameter value; and

limiting the alteration of the contents of said second memory by preventing the increase of said stimulation pulse parameter value unless said stimulation pulse parameter value is less than said stimulation pulse parameter limit value.

25. A method according to claim 24 wherein the remotely generated programming signals include parameter value increase signals and wherein the altering step includes increasing said stimulation pulse parameter value upon receipt of said increase signals.

26. A method according to claim 24 wherein the stimulation pulse parameter limit value contained in said first memory is an upper pulse parameter limit value and wherein the method further comprises programming a third memory with a lower pulse parameter limit value and altering the contents of said third memory in accordance with said remotely generated programming signals, and wherein the comparing step includes comparing said upper pulse parameter limit value, said stimulation pulse parameter value and said lower pulse parameter limit value, the method further including limiting the alteration of the contents of said second memory by preventing the increase of said stimulation pulse parameter value unless said stimulation pulse parameter value is less than said upper pulse parameter limit value and by preventing the decrease of said stimulation pulse parameter value unless said stimulation pulse parameter value is greater than said lower pulse parameter limit value.

27. A method according to claim 26 wherein the remotely generated programming signals include parameter value increase signals and parameter value decrease signals, and wherein the altering step includes increasing said stimulation pulse parameter value upon receipt of said increase signals and decreasing said stimulation pulse parameter value upon receipt of said decrease signals.

28. A method according to claim 24 wherein said stimulation pulse parameter limit value is one of stimulation pulse amplitude limit value, stimulation pulse rate limit value and stimulation pulse width limit value.

29. A method of limiting the programmability of a stimulation pulse parameter of an implantable tissue stimulator comprising:

programming a first memory with a stimulation pulse parameter limit value;

programming a second memory with a stimulation pulse parameter value;

receiving remotely generated programming signals;

altering the contents of at least one of said first and second memories in accordance with said programming signals;

comparing said stimulation pulse parameter limit value and said stimulation pulse parameter value; and

limiting the alteration of the contents of said second memory by preventing the decrease of said stimulation pulse parameter value unless said stimulation pulse parameter value is greater than said stimulation pulse parameter limit value.

30. A method according to claim 29 wherein the remotely generated programming signals include parameter value decrease signals and wherein the altering step includes decreasing said stimulation pulse parameter value upon receipt of said decrease signals.

31. A method according to claim 29 wherein said stimulation pulse parameter limit value is one of stimulation pulse amplitude limit value, stimulation pulse rate limit value and stimulation pulse width limit value.

32. A method of limiting the programmability of a stimulation pulse parameter of an implantable tissue stimulator comprising:

programming a first memory with a first stimulation pulse parameter limit value and a first stimulation pulse parameter value;

receiving remotely generated programming signals;

altering the contents of said first memory in accordance with said programming signals;

comparing said first stimulation pulse parameter limit value and said first stimulation pulse parameter value; and

limiting the alteration of the contents of said first memory by preventing the increase of said stimulation pulse parameter value unless said first stimulation pulse parameter value is less than said first stimulation pulse parameter limit value.

33. A method according to claim 32 further comprising programming a second memory with a second stimulation pulse parameter limit value and a second stimulation pulse parameter value, the method further including altering the contents of said second memory in accordance with said remotely generated programming signals, and wherein the comparing step includes comparing said second stimulation pulse parameter limit value and said second stimulation pulse parameter value and wherein the limiting step includes preventing the increase of said second stimulation pulse parameter value unless said second stimulation pulse parameter value is less than said second stimulation pulse parameter limit value.

34. A method according to claim 33 further comprising programming a third memory with a third stimulation pulse parameter limit value and a third stimulation pulse parameter value, the method further including altering the contents of said third memory in accordance with said remotely generated programming signals, and wherein the comparing step includes comparing said third stimulation pulse parameter limit value and said third stimulation pulse parameter value and wherein the limiting step includes preventing the increase of said third stimulation pulse parameter value unless said third stimulation pulse parameter value is less than said third stimulation pulse parameter limit value.

35. A method according to claim 34 wherein said first, second and third stimulation pulse parameter limit values contained in said first, second and third memories each comprise an upper pulse parameter limit value and a lower pulse parameter limit value, and wherein the comparing step includes comparing the upper and lower pulse parameter limit values of said first stimulation pulse parameter limit value to said first stimulation pulse parameter value, the upper and lower pulse parameter limit values of said second stimulation pulse parameter limit value to said second stimulation pulse parameter value and the upper and lower pulse parameter limit values of said third stimulation pulse parameter limit value to said third stimulation pulse parameter value, and wherein the limiting step includes preventing the increase of the value of said first stimulation pulse parameter value unless said first stimulation pulse parameter value is less than said upper parameter limit value and preventing the decrease of said first stimulation pulse parameter value unless said first stimulation pulse parameter value is greater than said lower parameter limit value of said first stimulation pulse parameter limit value, preventing the increase of the value of said second stimulation pulse parameter value unless said second stimulation pulse parameter value is less than said upper parameter limit value and preventing the decrease of said second stimulation pulse parameter value unless said second stimulation pulse parameter value is greater than said lower parameter limit value of said second stimulation pulse parameter limit value, and preventing the increase of the value of said third stimulation pulse parameter value unless said third stimulation pulse parameter value is less than said upper parameter limit value and preventing the decrease of said third stimulation pulse parameter value unless said third stimulation pulse parameter value is greater than said lower parameter limit value of said third stimulation pulse parameter limit value.

36. A method according to claim 35 wherein said remotely generated programming signals include at least one of first, second and third programmed parameter value increase signals and first, second and third programmed parameter value decrease signals, and wherein said altering step includes increasing said first stimulation pulse parameter value upon receipt of said first programmed parameter increase signals and decreasing said first stimulation pulse parameter value upon receipt of said first programmed parameter decrease signals, said altering step further including increasing said second stimulation pulse parameter value upon receipt of said second programmed parameter value increase signals and decreasing said second stimulation pulse parameter value upon receipt of said second programmed parameter decrease signals, said altering step further including increasing said third stimulation pulse parameter value upon receipt of said third programmed parameter value increase signals and decreasing said third stimulation pulse parameter value upon receipt of said third programmed parameter decrease signals.

37. A method according to claim 34 wherein said remotely generated programming signals include at least one of first, second and third programmed parameter value increase signals, and wherein the altering step includes increasing said first stimulation signal parameter value upon receipt of said first programmed parameter increase signals, increasing said second stimulation pulse parameter value upon receipt of said second programmed parameter increase signals, and increasing said third stimulation pulse parameter value upon receipt of said third programmed parameter increase signals.

38. A method according to claim 33 wherein said first and second stimulation pulse parameter limit values contained in said first and second memories each comprise an upper pulse parameter limit value and a lower pulse parameter limit value and wherein the comparing step includes comparing the upper and lower pulse parameter limit values of said first stimulation pulse parameter limit value to said first programmed parameter value and the upper and lower pulse parameter limit values of said second parameter limit value to said second programmed parameter value and wherein the limiting step includes preventing the increase of the value of said first stimulation pulse parameter value unless said first programmed parameter value is less than said upper parameter limit value and preventing the decrease of the value of said first stimulation pulse parameter value unless said first stimulation pulse parameter value is greater than said lower parameter limit value of said first stimulation pulse parameter limit value and further preventing the increase of the value of said second stimulation pulse parameter value unless said second stimulation pulse parameter value is less than said upper parameter limit value and preventing the decrease of the value of said second stimulation pulse parameter value unless said second stimulation pulse parameter value is greater than said lower parameter limit value of said second stimulation pulse parameter limit value.

39. A method according to claim 38 wherein said remotely generated programming signals include at least one of first and second programmed parameter value increase signals and first and second programmed parameter value decrease signals, and wherein said altering step includes increasing said first stimulation pulse parameter value upon receipt of said first programmed parameter increase signals and decreasing said first stimulation pulse parameter value upon receipt of said first programmed parameter decrease signals, said altering step further including increasing said second stimulation pulse parameter value upon receipt of said second programmed parameter value increase signals and decreasing said second stimulation pulse parameter value upon receipt of said second programmed parameter decrease signals.

40. A method according to claim 33 wherein said remotely generated programming signals include first and second stimulation pulse parameter value increase signals, and wherein the altering step includes increasing said first stimulation pulse parameter value upon receipt of said first stimulation pulse parameter increase signals and increasing said second stimulation pulse parameter value upon receipt of said second stimulation pulse parameter increase signals.

41. A method according to claim 32 wherein the first stimulation pulse parameter limit value contained in said first memory comprises an upper pulse parameter limit value and a lower pulse parameter limit value and wherein the comparing step includes comparing said upper pulse parameter limit value, said first stimulation pulse parameter value and said lower pulse parameter limit value and wherein the limiting step includes preventing the increase of the value of said first stimulation pulse parameter value unless said first stimulation pulse parameter value is less than said upper parameter limit value and preventing the decrease of the value of said first stimulation pulse parameter value unless said first stimulation pulse parameter value is greater than said lower parameter limit value.

42. A method according to claim 41 wherein said remotely generated programming signals include at least one of first programmed parameter value increase signals and first programmed parameter value decrease signals, and wherein the altering step includes increasing said first programmed parameter value upon receipt of said first programmed parameter increase signals and decreasing said first programmed parameter value upon receipt of said first programmed parameter decrease signals.

43. A method according to claim 32 wherein the remotely generated programming signals include parameter value increase signals and wherein the altering step includes increasing said stimulation pulse parameter value upon receipt of said increase signals.

44. A method of controlling the programmability of stimulation pulse parameters of an implantable electrical tissue stimulator comprising:

programming a pulse rate memory with upper and lower stimulation pulse rate limit values of a stimulation pulse and a first programmed pulse rate value of said stimulation pulse;

programming a pulse width memory with upper and lower stimulation pulse width limit values of a stimulation pulse and a first programmed pulse width value of said stimulation pulse;

programming a pulse amplitude memory with upper and lower stimulation pulse amplitude limit values of a stimulation pulse and a first programmed pulse amplitude value of said stimulation pulse;

receiving remotely generated programming signals;

altering the contents of at least one of said pulse rate, pulse width and pulse amplitude memories in accordance with said remotely generated signals; and

comparing said pulse rate, pulse width and pulse amplitude limit values with said first programmed pulse rate, pulse width and pulse amplitude values, respectively; and

preventing the increase of said first programmed pulse rate value unless the first programmed pulse rate value is less than said upper stimulation pulse rate limit value and preventing the decrease of said first programmed pulse rate value unless said first programmed pulse rate value is greater than said lower stimulation pulse rate limit value, further preventing the increase of said first programmed pulse width value unless said first programmed pulse width value is less than said upper stimulation pulse width limit value and preventing the decrease of said first programmed pulse width value unless said first programmed pulse width value is greater than said lower stimulation pulse width limit value, further preventing the increase of said first programmed pulse amplitude value unless said first programmed pulse amplitude value is less than said upper stimulation pulse amplitude limit value and preventing the decrease of said first programmed pulse amplitude value unless said first programmed pulse amplitude value is greater than said lower stimulation pulse amplitude limit value.