CA1175493A - Keyboard-controlled microprocessor-based nerve stimulator - Google Patents
Keyboard-controlled microprocessor-based nerve stimulatorInfo
- Publication number
- CA1175493A CA1175493A CA000401817A CA401817A CA1175493A CA 1175493 A CA1175493 A CA 1175493A CA 000401817 A CA000401817 A CA 000401817A CA 401817 A CA401817 A CA 401817A CA 1175493 A CA1175493 A CA 1175493A
- Authority
- CA
- Canada
- Prior art keywords
- switch
- output
- user
- microprocessor
- tissue stimulator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
- A61N1/36014—External stimulators, e.g. with patch electrodes
- A61N1/36021—External stimulators, e.g. with patch electrodes for treatment of pain
-
- 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
- A61N1/36014—External stimulators, e.g. with patch electrodes
- A61N1/3603—Control systems
-
- 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
- A61N1/37247—User interfaces, e.g. input or presentation means
Abstract
ABSTRACT OF THE DISCLOSURE
A keyboard-controlled microprocessor-based tissue stimulator includes pulse output circuits which deliver output pulses at times commanded by, and having amplitudes commanded by, a microprocessor-controller. A microprocessor operates in response to user command on keyboard switches. Commands include a stop command which not only terminates output pulses but resets amplitudes to a safe value so that subsequent restarting will not result in production of uncomfortably high output signal levels.
The stop switch is prominently located on the tissue stimulator housing to permit the user to stop operation very quickly in an emergency situation. Keyboard switches are provided for increas-ing and decreasing output amplitude, and the microprocessor-controller responds to those commands by continuously changing output amplitude by predetermined small increments for as long as the switch remains depressed, thus permitting the user to make smooth and precise adjustments for optimum results. A further keyboard switch commands the microprocessor-controller to switch to an alternate mode, for example, a low rate burst mode.
A keyboard-controlled microprocessor-based tissue stimulator includes pulse output circuits which deliver output pulses at times commanded by, and having amplitudes commanded by, a microprocessor-controller. A microprocessor operates in response to user command on keyboard switches. Commands include a stop command which not only terminates output pulses but resets amplitudes to a safe value so that subsequent restarting will not result in production of uncomfortably high output signal levels.
The stop switch is prominently located on the tissue stimulator housing to permit the user to stop operation very quickly in an emergency situation. Keyboard switches are provided for increas-ing and decreasing output amplitude, and the microprocessor-controller responds to those commands by continuously changing output amplitude by predetermined small increments for as long as the switch remains depressed, thus permitting the user to make smooth and precise adjustments for optimum results. A further keyboard switch commands the microprocessor-controller to switch to an alternate mode, for example, a low rate burst mode.
Description
~ 175493 The present invention pertains to the field of tissue stimulators. In particular, the invention pertains to an improved tissue stimulator pulse generator in which the operation is controlled by the user through a keyboard, which controls a microprocessor which in turn controls the output pulse generator.
Tissue stimulators have gained wide acceptance in the field of medicine for the treatment of chronic, intractable pain.
Tissue stimulators include electrical circuits for generating electrical pulses, and leads and electrodes which convey electrical pulses to the affected part of the body. In some cases the entire tissue stimulator system is intended to be implanted within the body. In other cases, the pulse generating circuitry is contained in a box or package externally of the body, usually adapted to be worn or carried by the patient.
Electrical leads connect from the pulse generator to electrodes which are in contact with the body. In the case of transcutaneous tissue stimulators, the electrodes have a significant surface area in contact with the skin and are held in place by adhesives, etc., over the affected areas. In other cases, the leads are introduced through the skin to an implanted electrode, for example, along the spinal cord. In either case the electrical impulses travel through the skin or body tissues and produce the effect of relieving the sensation of pain. Controls are usually provided on the pulse generator to control the amplitude of the output pulses, and possibly other parameters to enable adjusting the device for optimum results. Tissue stimulators have achieved widespread acceptance because of their ability to deal with pain without the use of drugs and their possible harmful side effects.
1 175~93 Most adjustable prior art tissue stimulators use potentiometers to control the output pulse amplitude. The patient will typically turn the apparatus on and off for intervals of time, and adjust the setting of the amplitude potentiometer as required according to changes in the amount of perceived pain, variations in the electrical coupling efficiency between the electrode and skin, and various other factors.
These types of prior art devices are subject to a certain disadvantage in operation, in that when the patient turns the device on, there is a possibility that the output potentiometer setting from the previous usage may be too high for the present usage, resulting in an unpleasant sensation. This requires the patient to quickly try to locate the control potentiometer or off switch to correct this situation. Since most devices are designed for multiple channel operation, it may be difficult under those circumstances to locate the output level control potentiometer for the correct channel quickly.
Another problem with potentiometer controls is their relatively poor resolution which makes it difficult for a person to make fine adjustments to achieve optimum results.
The present invention overcomes those difficulties by providing an improved keyboard-operated, microprocessor-based tissue stimulator which reduces output amplitude to zero, or to a safe, low value, each time the device is turned off. When it is subsequently turned on, the patient can gradually turn up the output to the desired level. In this manner, the unpleasant sensation sometimes produced by prior art tissue stimulators due ~17~493 to turn-on at too high an output level is avoided.
Thus, in accordance with a broad aspect of the invention, there is provided a tissue stimulator of the type comprising a housing adapted to be worn or carried by a user of the tissue stimulator, a controlled pulse generating circuit means operable for producing output stimulating pulses having amplitude times controlled in response to control signals received by the pulse generating means, user-actuable switch means for commanding changes in output pulse amplitude, and a user-actuable stop switch for discontinuation of output pulses characterized by: micro-processor control means operative in response to the user-actuable switch means for providing control signals to said pulse generat-ing means to produce periodic output stimulating pulses, said microprocessor control means responsive to cause a change in output pulse amplitude in response to a command from the user-actuable switch means, and further operable to reduce output pulse amplitude prior to resumption of output pulses.
According to another aspect of the invention, a large prominently placed OFF switch is provided on the tissue stimulator unit to permit the patient to turn the device off instantly if it should become necessary to do so for any reason.
According to another aspect of the invention, a control keyboard is provided with a switch for automatically switching the microprocessor to an alternate form or mode of stimulation, i.e.
for example a low-rate burst mode.
According to another aspect of the invention, keyboard controls are provided for operating in con~unction with the ~5493 microprocessor controller, for incrementing or decrementing output pulse amplitude, with changes being controllable by high resolution increments.
Brief Description of the Drawings In the drawing, Figure 1 is a view in perspective of a tissue stimulator pulse generator having a control keyboard according to the present invention;
Figure 2 is a block diagram of the keyboard-controlled microprocessor-based tissue stimulator of the present invention;
and Figures 3A and 3B are flow charts illustrating the operation of the tissue stimulator of Figure 2.
Detailed Description of the Preferred Embodiment In Figure 1, reference 10 generally designates a tissue stimulator according to the present invention. Stimulator 10 includes a housing 11 which contains the pulse generating and control circuitry, described below. The preferred embodiment shown is a two channel device and it includes a pair of output terminals 12 and another pair of output terminals 13. These output terminals can take the form of sockets which receive mating plugs on the ends of electrode leads. Stimulator 10 typically would include a belt clip (not shown) or other means as is generally known in the art for enabling a patient to wear the device. In use, electrodes (not shown) as are generally known in the art would be applied to the affected areas of the body for which treatment is desired, and the leads thereof connected into terminals 12 and 13, so that the device can provide tissue 1 17~493 stimulation to the affected areas.
Stimulator 10 includes a keyboard 15 which includes a number of separate controls. These include an OFF switch 16, and ON switch 17, a LOW RATE switch 18, and channel output control switches 20-23. Switch 20 is labeled with appropriate indicia for increasing channel one output, and switch 21 is labeled for decreasing channel one output. Similarly, switches 22 and 23 are labeled for increasing and decreasing, respectively, the channel two output. The preferred embodîment shown is a two channel device; however, it will be understood that the invention is also equally applicable to stimulators having a lesser or greater number of channels. The keyboard switches can be of any type, for example, membrane switches, discrete switches with separate push buttons, etc., as the type of switch is not critical to the present invention.
The preferred form of the invention uses a sliding keyboard cover 25 for protecting the switches against inadvertent actuation. Briefly, in one position the cover provides access to all switches for adjusting settings. In the protective position, the cover blocks all switches but the OFF switch 16. While preferred, the sliding protective cover is not necessary to the practice of the present invention.
Referring now to Figure 2, the circuitry for the tissue stimulator is shown in block diagram form. The microprocessor includes a central processing unit (CPU) 30 and a read only memory (ROM) 31 which may or may not be on the same chip as CPU 30, depending upon the manufacturer of the microprocessor. Keyboard 15 and the various switches thereof are in data communication with CPU 30 as indicated by data bus 32, except that ON switch 17 connects to flip-flop 34 by lead 35. ROM 31, which contains the program instructions, is also in communication with CPU 30, via data bus 33. A battery or other power supply is provided within the device for powering the control and output circuitry, but it has been omitted from Figure 2 for purposes of clarity. Flip-flop 34, which remains permanently powered, but which draws very little current, is connected for switching power from the battery to the various circuits. It is set by ON switch 17 and reset to power-down by CPU 30, in response to actuation of OFF switch 16.
CPU 30 communicates with a pulse output circuit 40 via a plurality of data lines represented by data line 41 for channel one, or data line 42 for channel two. Circuit 40 contains separate output circuits for the two channels, or alternatively, a single output circuit and switching devices for connecting it successively to the separate output terminals for the channels.
The design of the pulse output circuits is conventional and there-fore not shown in detail. The preferred form of the invention uses the type of output circuit 40 which controls the pulse output amplitude according to the width of the control pulse applied.
This can be done, for example, with the type of output circuit that uses stored energy in an inductor to provide the output energy. Control pulse 41 controls the build-up of current within the inductor, and at the termination of the control pulse, the stored energy from the inductor is transmitted out the output terminals.
The operation of the tissue stimulator will now be ~ .t754~3 illustrated with the aid of the program flow chart Figures 3A and 3B for the program used in the microprocessor.
In Figure 3A, step 50 is the start of the program, which is reached by turning on the stimulator by activation of ON switch 17. At step 51, program parameters are initialized, and in particular the amplitudes are set to zero ~O) output. Alternatively, they could be set to a safe nominal value.
Also at step 51, the rate control is returned to "normal", in case the device had previously been operating in "low rate" mode.
Control then proceeds to step 52, at which the rate flag is checked.
If the "low rate" switch 18 has been depressed, the rate flag will be set (from step 66 below), and control will branch to step 53. Step 53 is a pro-gram delay during which the microprocessor counts output pulses and provides delays, so as to provide the desired interval between output pulse bursts.
After step 53, or in the event that rate flag 52 was not set, control proceeds to step 54, at which it is determined whether a change in amplitude is being requested for channel one. This would be true if the patient were depressing either switch 20 or 21 to increase or decrease channel one output. If so, control branches to step 55, where it is determined whether an increase or decrease is called for. The appropriate increase or decrease is taken care of at steps 56 or 57. An internal register within the microprocessor used as a counter has a count which determines the pulse width output from the CPU
on line 41 to the pulse output circuits. This counter is either incremented or decremented at ~ ~ 75~93 step 56 or 57, respectively, Steps 60-63 correspond to steps 54-57, but apply to channel two. If either the channel one or channel two change is being called for, after incrementing or decrementing the appropriate register, control passes via branch 64 to the output routine beginning at step 70. Otherwise, control proceeds from step 60 to step 65 at which it is determined whether the "low rate" switch 18 is being depressed. If so, the rate flag is set at step 66, and control passes to branch 64. If not, step 67 determines whether the OFF switch 16 is being depressed. If so, step 68 shuts off power via circuit 34 to the microprocessor and output circuits to save power.
In the output routine, at step 70, the channel one output pulse is generated. Specifically, the CPU puts out a control signal on lead 41 having a duration determined by an internal counter for channel one. This is the counter-register whose count can be incremented or decremented at steps 56 or 57, above. The output pulse width from the CPU determines the tissue stimulator output pulse amplitude for channel one, as previously described.
The channel one and two outputs are offset from one another by delayed times, steps 71 and 73. Step 71 is the delay time between the channel one and channel two outputs, while step 73 is the delay time between the channel two and channel one outputs. Delays for steps 71 and 73 are also determined by counter-registers within the CPU. In the preferred embodiment, these delays are adjusted in cooperation with the basic program ~ 175~g3 execution speed of the device, so that the microprocessor will proceed through the normal operating loop at the desired speed, for example 85 times per second. This establishes the basic output pulse repetition rate of the device.
Also in the preferred embodiment, delay time 71 is altered at the same time that output pulse width 70 is altered, at step 56 or 57, so as to maintain the total times of steps 70 and 71, a constant value. Thus, if the time for step 70 is increased in response to actuation of switch 20, the delay tirne at step 71 will be correspondingly decreased. The same thing holds true for steps 72 and 73.
The low rate mode, which is believed to cause the body to produce its own morphine-like pain killers, applies bursts of pulses, separated by delay intervals. In low rate mode, step 53 of the flow chart, output pulses are counted, and after seven pulses per channel, a delay is executed, then seven further pulses are delivered, with three groups of seven pulses being produced each second.
The increment-decrement control of output amplitude has several advantages as compared to a potentiometer. The finest resolution practically achievable with pGtentiometers is approxi-mately 3% at best, and probably much worse than that. This makes it difficult for a person to make fine adjustments to obtain optimum output. The increment-decrement control of the present invention provides resolution steps of 1% or less, and can be programmed to as small steps as desired. Also, potentiometers have the possibility of providing unpleasantly high outputs almost ~ 175493 instantaneously, if the control knobs are moved or jerked too high. The increment control of the present invention takes place at a predictable smooth rate under program control, even if the increase switch is inadvertently pushed. Potentiometers do not permit practical use of a "panic" off switch because of the built-in memory effect of the potentiometer which would result in the same output level upon resumption of operation, unless the user remembered to turn them down. This could provide an unpleasantly high output level when the unit is restarted. This effect is avoided in the present invention, by the automatic reduction of output levels upon re-start.
Tissue stimulators have gained wide acceptance in the field of medicine for the treatment of chronic, intractable pain.
Tissue stimulators include electrical circuits for generating electrical pulses, and leads and electrodes which convey electrical pulses to the affected part of the body. In some cases the entire tissue stimulator system is intended to be implanted within the body. In other cases, the pulse generating circuitry is contained in a box or package externally of the body, usually adapted to be worn or carried by the patient.
Electrical leads connect from the pulse generator to electrodes which are in contact with the body. In the case of transcutaneous tissue stimulators, the electrodes have a significant surface area in contact with the skin and are held in place by adhesives, etc., over the affected areas. In other cases, the leads are introduced through the skin to an implanted electrode, for example, along the spinal cord. In either case the electrical impulses travel through the skin or body tissues and produce the effect of relieving the sensation of pain. Controls are usually provided on the pulse generator to control the amplitude of the output pulses, and possibly other parameters to enable adjusting the device for optimum results. Tissue stimulators have achieved widespread acceptance because of their ability to deal with pain without the use of drugs and their possible harmful side effects.
1 175~93 Most adjustable prior art tissue stimulators use potentiometers to control the output pulse amplitude. The patient will typically turn the apparatus on and off for intervals of time, and adjust the setting of the amplitude potentiometer as required according to changes in the amount of perceived pain, variations in the electrical coupling efficiency between the electrode and skin, and various other factors.
These types of prior art devices are subject to a certain disadvantage in operation, in that when the patient turns the device on, there is a possibility that the output potentiometer setting from the previous usage may be too high for the present usage, resulting in an unpleasant sensation. This requires the patient to quickly try to locate the control potentiometer or off switch to correct this situation. Since most devices are designed for multiple channel operation, it may be difficult under those circumstances to locate the output level control potentiometer for the correct channel quickly.
Another problem with potentiometer controls is their relatively poor resolution which makes it difficult for a person to make fine adjustments to achieve optimum results.
The present invention overcomes those difficulties by providing an improved keyboard-operated, microprocessor-based tissue stimulator which reduces output amplitude to zero, or to a safe, low value, each time the device is turned off. When it is subsequently turned on, the patient can gradually turn up the output to the desired level. In this manner, the unpleasant sensation sometimes produced by prior art tissue stimulators due ~17~493 to turn-on at too high an output level is avoided.
Thus, in accordance with a broad aspect of the invention, there is provided a tissue stimulator of the type comprising a housing adapted to be worn or carried by a user of the tissue stimulator, a controlled pulse generating circuit means operable for producing output stimulating pulses having amplitude times controlled in response to control signals received by the pulse generating means, user-actuable switch means for commanding changes in output pulse amplitude, and a user-actuable stop switch for discontinuation of output pulses characterized by: micro-processor control means operative in response to the user-actuable switch means for providing control signals to said pulse generat-ing means to produce periodic output stimulating pulses, said microprocessor control means responsive to cause a change in output pulse amplitude in response to a command from the user-actuable switch means, and further operable to reduce output pulse amplitude prior to resumption of output pulses.
According to another aspect of the invention, a large prominently placed OFF switch is provided on the tissue stimulator unit to permit the patient to turn the device off instantly if it should become necessary to do so for any reason.
According to another aspect of the invention, a control keyboard is provided with a switch for automatically switching the microprocessor to an alternate form or mode of stimulation, i.e.
for example a low-rate burst mode.
According to another aspect of the invention, keyboard controls are provided for operating in con~unction with the ~5493 microprocessor controller, for incrementing or decrementing output pulse amplitude, with changes being controllable by high resolution increments.
Brief Description of the Drawings In the drawing, Figure 1 is a view in perspective of a tissue stimulator pulse generator having a control keyboard according to the present invention;
Figure 2 is a block diagram of the keyboard-controlled microprocessor-based tissue stimulator of the present invention;
and Figures 3A and 3B are flow charts illustrating the operation of the tissue stimulator of Figure 2.
Detailed Description of the Preferred Embodiment In Figure 1, reference 10 generally designates a tissue stimulator according to the present invention. Stimulator 10 includes a housing 11 which contains the pulse generating and control circuitry, described below. The preferred embodiment shown is a two channel device and it includes a pair of output terminals 12 and another pair of output terminals 13. These output terminals can take the form of sockets which receive mating plugs on the ends of electrode leads. Stimulator 10 typically would include a belt clip (not shown) or other means as is generally known in the art for enabling a patient to wear the device. In use, electrodes (not shown) as are generally known in the art would be applied to the affected areas of the body for which treatment is desired, and the leads thereof connected into terminals 12 and 13, so that the device can provide tissue 1 17~493 stimulation to the affected areas.
Stimulator 10 includes a keyboard 15 which includes a number of separate controls. These include an OFF switch 16, and ON switch 17, a LOW RATE switch 18, and channel output control switches 20-23. Switch 20 is labeled with appropriate indicia for increasing channel one output, and switch 21 is labeled for decreasing channel one output. Similarly, switches 22 and 23 are labeled for increasing and decreasing, respectively, the channel two output. The preferred embodîment shown is a two channel device; however, it will be understood that the invention is also equally applicable to stimulators having a lesser or greater number of channels. The keyboard switches can be of any type, for example, membrane switches, discrete switches with separate push buttons, etc., as the type of switch is not critical to the present invention.
The preferred form of the invention uses a sliding keyboard cover 25 for protecting the switches against inadvertent actuation. Briefly, in one position the cover provides access to all switches for adjusting settings. In the protective position, the cover blocks all switches but the OFF switch 16. While preferred, the sliding protective cover is not necessary to the practice of the present invention.
Referring now to Figure 2, the circuitry for the tissue stimulator is shown in block diagram form. The microprocessor includes a central processing unit (CPU) 30 and a read only memory (ROM) 31 which may or may not be on the same chip as CPU 30, depending upon the manufacturer of the microprocessor. Keyboard 15 and the various switches thereof are in data communication with CPU 30 as indicated by data bus 32, except that ON switch 17 connects to flip-flop 34 by lead 35. ROM 31, which contains the program instructions, is also in communication with CPU 30, via data bus 33. A battery or other power supply is provided within the device for powering the control and output circuitry, but it has been omitted from Figure 2 for purposes of clarity. Flip-flop 34, which remains permanently powered, but which draws very little current, is connected for switching power from the battery to the various circuits. It is set by ON switch 17 and reset to power-down by CPU 30, in response to actuation of OFF switch 16.
CPU 30 communicates with a pulse output circuit 40 via a plurality of data lines represented by data line 41 for channel one, or data line 42 for channel two. Circuit 40 contains separate output circuits for the two channels, or alternatively, a single output circuit and switching devices for connecting it successively to the separate output terminals for the channels.
The design of the pulse output circuits is conventional and there-fore not shown in detail. The preferred form of the invention uses the type of output circuit 40 which controls the pulse output amplitude according to the width of the control pulse applied.
This can be done, for example, with the type of output circuit that uses stored energy in an inductor to provide the output energy. Control pulse 41 controls the build-up of current within the inductor, and at the termination of the control pulse, the stored energy from the inductor is transmitted out the output terminals.
The operation of the tissue stimulator will now be ~ .t754~3 illustrated with the aid of the program flow chart Figures 3A and 3B for the program used in the microprocessor.
In Figure 3A, step 50 is the start of the program, which is reached by turning on the stimulator by activation of ON switch 17. At step 51, program parameters are initialized, and in particular the amplitudes are set to zero ~O) output. Alternatively, they could be set to a safe nominal value.
Also at step 51, the rate control is returned to "normal", in case the device had previously been operating in "low rate" mode.
Control then proceeds to step 52, at which the rate flag is checked.
If the "low rate" switch 18 has been depressed, the rate flag will be set (from step 66 below), and control will branch to step 53. Step 53 is a pro-gram delay during which the microprocessor counts output pulses and provides delays, so as to provide the desired interval between output pulse bursts.
After step 53, or in the event that rate flag 52 was not set, control proceeds to step 54, at which it is determined whether a change in amplitude is being requested for channel one. This would be true if the patient were depressing either switch 20 or 21 to increase or decrease channel one output. If so, control branches to step 55, where it is determined whether an increase or decrease is called for. The appropriate increase or decrease is taken care of at steps 56 or 57. An internal register within the microprocessor used as a counter has a count which determines the pulse width output from the CPU
on line 41 to the pulse output circuits. This counter is either incremented or decremented at ~ ~ 75~93 step 56 or 57, respectively, Steps 60-63 correspond to steps 54-57, but apply to channel two. If either the channel one or channel two change is being called for, after incrementing or decrementing the appropriate register, control passes via branch 64 to the output routine beginning at step 70. Otherwise, control proceeds from step 60 to step 65 at which it is determined whether the "low rate" switch 18 is being depressed. If so, the rate flag is set at step 66, and control passes to branch 64. If not, step 67 determines whether the OFF switch 16 is being depressed. If so, step 68 shuts off power via circuit 34 to the microprocessor and output circuits to save power.
In the output routine, at step 70, the channel one output pulse is generated. Specifically, the CPU puts out a control signal on lead 41 having a duration determined by an internal counter for channel one. This is the counter-register whose count can be incremented or decremented at steps 56 or 57, above. The output pulse width from the CPU determines the tissue stimulator output pulse amplitude for channel one, as previously described.
The channel one and two outputs are offset from one another by delayed times, steps 71 and 73. Step 71 is the delay time between the channel one and channel two outputs, while step 73 is the delay time between the channel two and channel one outputs. Delays for steps 71 and 73 are also determined by counter-registers within the CPU. In the preferred embodiment, these delays are adjusted in cooperation with the basic program ~ 175~g3 execution speed of the device, so that the microprocessor will proceed through the normal operating loop at the desired speed, for example 85 times per second. This establishes the basic output pulse repetition rate of the device.
Also in the preferred embodiment, delay time 71 is altered at the same time that output pulse width 70 is altered, at step 56 or 57, so as to maintain the total times of steps 70 and 71, a constant value. Thus, if the time for step 70 is increased in response to actuation of switch 20, the delay tirne at step 71 will be correspondingly decreased. The same thing holds true for steps 72 and 73.
The low rate mode, which is believed to cause the body to produce its own morphine-like pain killers, applies bursts of pulses, separated by delay intervals. In low rate mode, step 53 of the flow chart, output pulses are counted, and after seven pulses per channel, a delay is executed, then seven further pulses are delivered, with three groups of seven pulses being produced each second.
The increment-decrement control of output amplitude has several advantages as compared to a potentiometer. The finest resolution practically achievable with pGtentiometers is approxi-mately 3% at best, and probably much worse than that. This makes it difficult for a person to make fine adjustments to obtain optimum output. The increment-decrement control of the present invention provides resolution steps of 1% or less, and can be programmed to as small steps as desired. Also, potentiometers have the possibility of providing unpleasantly high outputs almost ~ 175493 instantaneously, if the control knobs are moved or jerked too high. The increment control of the present invention takes place at a predictable smooth rate under program control, even if the increase switch is inadvertently pushed. Potentiometers do not permit practical use of a "panic" off switch because of the built-in memory effect of the potentiometer which would result in the same output level upon resumption of operation, unless the user remembered to turn them down. This could provide an unpleasantly high output level when the unit is restarted. This effect is avoided in the present invention, by the automatic reduction of output levels upon re-start.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A tissue stimulator of the type comprising a housing adapted to be worn or carried by a user of the tissue stimulator, a controlled pulse generating circuit means operable for producing output stimulating pulses having amplitude times controlled in response to control signals received by the pulse generating means, user-actuable switch means for commanding changes in output pulse amplitude, and a user-actuable stop switch for discontinua-tion of output pulses characterized by:
microprocessor control means operative in response to the user-actuable switch means for providing control signals to said pulse generating means to produce periodic output stimulating pulses, said microprocessor control means responsive to cause a change in output pulse amplitude in response to a command from the user-actuable switch means, and further operable to reduce output pulse amplitude prior to resumption of output pulses.
microprocessor control means operative in response to the user-actuable switch means for providing control signals to said pulse generating means to produce periodic output stimulating pulses, said microprocessor control means responsive to cause a change in output pulse amplitude in response to a command from the user-actuable switch means, and further operable to reduce output pulse amplitude prior to resumption of output pulses.
2. A tissue stimulator according to claim 1 wherein said user-actuable stop switch is prominently positioned on the housing to facilitate rapid turn off of the tissue stimulator under emergency situations and wherein said microprocessor control means is operable to discontinue output pulses in response to actuation of the stop switch.
3. A tissue stimulator according to claim 1 including a further user-actuable switch for commanding a burst mode of operation, and wherein said microprocessor control means includes means responsive to actuation of said burst command switch for causing said pulse generating means to produce periodic output stimulation pulses in groups, with subsequent groups being separated by delay intervals.
4. A tissue stimulator according to claim 1 wherein said user-actuable means for controlling output pulse amplitude includes an increase command switch and a decrease command switch, and wherein said microprocessor control means includes means responsive to said increase switch for causing an increase in output amplitude, and means responsive to said decrease switch for causing a decrease in output pulse amplitude.
5. A tissue stimulator according to claim 4 wherein said microprocessor control means includes means for continually incrementing, or decrementing, respectively, the output pulse amplitude by predetermined increments as long as the increase switch or decrease switch, respectively, remains actuated.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US25891881A | 1981-04-30 | 1981-04-30 | |
| US258,918 | 1981-04-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1175493A true CA1175493A (en) | 1984-10-02 |
Family
ID=22982689
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000401817A Expired CA1175493A (en) | 1981-04-30 | 1982-04-28 | Keyboard-controlled microprocessor-based nerve stimulator |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1175493A (en) |
| DE (1) | DE3216220A1 (en) |
| ES (1) | ES8303925A1 (en) |
| FR (1) | FR2504807A1 (en) |
| SE (1) | SE8202727L (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4832033A (en) * | 1985-04-29 | 1989-05-23 | Bio-Medical Research Limited | Electrical stimulation of muscle |
| US5033469A (en) * | 1987-11-12 | 1991-07-23 | Medicompex S.A. | Installation for neuromuscular electrical stimulation |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4770328A (en) * | 1982-12-16 | 1988-09-13 | Medtronic, Inc. | Tissue stimulator casing |
| DE3344831A1 (en) * | 1983-12-07 | 1985-06-13 | Robert Bosch Gmbh, 7000 Stuttgart | Single- or multi-channel stimulating-current device |
| EP0268701A1 (en) * | 1986-11-26 | 1988-06-01 | JAMUTRON GERÄTEBAU GmbH | Electric stimulator for medical and cosmetic applications |
| US5184617A (en) * | 1990-06-05 | 1993-02-09 | Staodyn, Inc. | Output pulse compensation for therapeutic-type electronic devices |
| GB2278547A (en) * | 1993-05-26 | 1994-12-07 | Robinson & Sons Ltd | Neuro-muscular stimulator |
| US8140165B2 (en) | 2005-01-28 | 2012-03-20 | Encore Medical Asset Corporation | Independent protection system for an electrical muscle stimulation apparatus and method of using same |
| WO2006113801A2 (en) | 2005-04-19 | 2006-10-26 | Compex Technologies, Inc. | Electrical stimulation device and method for therapeutic treatment and pain management |
| US8620438B1 (en) | 2007-02-13 | 2013-12-31 | Encore Medical Asset Corporation | Method and apparatus for applying neuromuscular electrical stimulation |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4147171A (en) * | 1977-01-28 | 1979-04-03 | Greene Ronald W | Transcutaneous pain control and/or muscle stimulating apparatus |
| US4324253A (en) * | 1977-01-28 | 1982-04-13 | Greene Ronald W | Transcutaneous pain control and/or muscle stimulating apparatus |
| US4210150A (en) * | 1977-06-27 | 1980-07-01 | Staodynamics, Inc. | Miniaturized transcutaneous nerve stimulating device |
| US4121594A (en) * | 1977-09-26 | 1978-10-24 | Med General, Inc. | Transcutaneous electrical nerve stimulator |
| US4177819A (en) * | 1978-03-30 | 1979-12-11 | Kofsky Harvey I | Muscle stimulating apparatus |
-
1982
- 1982-04-28 CA CA000401817A patent/CA1175493A/en not_active Expired
- 1982-04-29 ES ES511800A patent/ES8303925A1/en not_active Expired
- 1982-04-30 FR FR8207570A patent/FR2504807A1/en active Pending
- 1982-04-30 DE DE19823216220 patent/DE3216220A1/en not_active Withdrawn
- 1982-04-30 SE SE8202727A patent/SE8202727L/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4832033A (en) * | 1985-04-29 | 1989-05-23 | Bio-Medical Research Limited | Electrical stimulation of muscle |
| US5033469A (en) * | 1987-11-12 | 1991-07-23 | Medicompex S.A. | Installation for neuromuscular electrical stimulation |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8202727L (en) | 1982-10-31 |
| FR2504807A1 (en) | 1982-11-05 |
| ES511800A0 (en) | 1983-02-16 |
| ES8303925A1 (en) | 1983-02-16 |
| DE3216220A1 (en) | 1982-11-18 |
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