Microprocessor-controlled enhanced multiplexed functional electrical stimulator for surface stimulation in paralyzed patients

• US 5,081,989 A
• Filed: 04/26/1990
• Issued: 01/21/1992
• Est. Priority Date: 04/07/1989
• Status: Expired due to Fees

• Current Assignee: Sigmedics, Inc.
• Original Assignee: Sigmedics, Inc.
• Inventors: Romeo, Silvano A., Arber, Amihadar, Graupe, Daniel
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/515,163
• Time in Patent Office: 635 Days
• Field of Search: 128/419 R, 128/421, 128/422, 128/420.5, 128/420.6, 128/903, 128/423 W
• US Class Current: 607/63
• CPC Class Codes: A61F 4/00 Methods or devices enabling patients or disabled persons to operate an apparatus or a device not forming part of the body operating or control means for prostheses A61F2/48, A61F2/68
• CPC Class Codes: A61N 1/36003 of motor muscles, e.g. for walking assistance

Abstract

In accordance with the present invention, a functional electrical stimulation system enables upper-motor-neuron paraplegic patients and certain other paralyzed or partially paralyzed patients to stand and to take steps with the support of a walker in an independent fashion so that they are in control of the stimulation and, noting that they have very little or no sensation, that they still can obtain some feedback on the state of the system. In one embodiment, a compact and safe battery-operated stimulation system is provided that is of pocket size and that allows for non-invasive save and controlled stimulation using skin surface electrodes. The system of the present invention is a stimulation system for providing upper-motor-neuron paralyzed patients with capabilities of unbraced standing and unbraced walking, which consists of a single pulse power and amplifier that outputs various trains of stimulation pulses and which is totally under microprocessor generation and control, where the microprocessor`s microcomputer selectively performs multiplexing of the pulse trains and their selective alternate distribution to the various surface electrodes attached to the skin of the patient at the appropriate stimulation locations. It also controls pulse-width, pulse-frequency, pulse-amplitude and pulse-shape.

The system measures, analyzes, computes, activates and implements safety measures to protect the patient during steps, when sitting down, and in case of a malfunctioning electrode.

Claims

1. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means; and

,

opto-isolator means, for coupling between said multiplexer means outputs and said electrodes, for buffering and optically and electrically isolating said outputs coupling to said electrodes and said electrical stimulation system.

2. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein during the "take left step" mode the pulse outputs are selectively outputted to the right quadriceps channel and left peroneal channel, while at the same time no stimulus is outputted to the left quadriceps muscle and to the right peroneal nerve;

said output to the right quadriceps channel being increased by a predefined amount during the time that no stimulus is being output to the left quadriceps channel.

3. The system as in claim 2 wherein said predefined amount is on the order of 10-20% above the immediately preceding output.

4. The system as in claim 3 wherein said predefined amount is 15%.

5. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein during the "take right step" mode the pulse outputs are selectively outputted to the left quadriceps channel and the right peroneal channel, while at the same time no stimulus is outputted to the right quadriceps muscle and to the left peroneal nerve, said outputted to the left quadriceps channel being increased by a predefined amount during the time that no stimulus is being output to the right quadriceps channel.

6. The system as in claim 5 wherein said predefined amount is on the order of 10-20% above the immediately preceding output level.

7. The system as in claim 6 wherein said predefined amount is 15%.

8. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient.

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, one adapted to contact to the right gluteus maximus muscle and one adapted to contact to the left gluteus maximus muscle;

wherein in said sit down mode the amplitude of the pulses to the right and left quadriceps channels is initially increased by a predefined amount, for a predetermined time duration, and wherein thereafter the amplitude of the pulse outputs to the right and left quadriceps channels and to the right and left gluteus maximus channels are gradually reduced to zero, over a predetermined time period on the order of seconds.

9. The systems as in claim 8 wherein said predefined amount is in the range of 10-20% above the immediately preceding amplitude levels.

10. The system as in claim 9 wherein said predefined amount is 15%.

11. The system as in claim 10 wherein said predetermined time duration is on the order of seconds.

16. The system as in claim 8 wherein said amplitude level increase comprises an increasing peak voltage of the pulse.

12. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, wherein there are at least two channels one adapted to contact to the right leg quadriceps muscle and one adapted to contact to the left leg quadriceps muscle;

means for detecting a drop below a predefined threshold level in output current level of said output of said multiplexer means, and responsive to detecting said drop, to automatically activate an audible alarm, and automatically disallowing left and right step modes.

13. The system as in claim 12, said means for detecting comprises means for measuring said drop in output current level as a change in an electrical voltage drop over an impedance in parallel to the output to the stimulation electrode.

14. The system as in claim 12, said means for detecting comprises means for measuring said drop in output current level as a change in an electrical voltage drop over an impedance in series with the output to the stimulation electrodes.

15. The system as in claim 12, said means for detecting comprises means for measuring said drop in output current level as electrical impedance drop.

17. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between slected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrode are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein during the take left step mode the pulse outputs are selectively output to the right quadriceps channel and left peroneal channel, while at the same time no stimulus is outputted to the left quadriceps muscle and to the left peroneal nerve;

said output to the right quadriceps and to the left take step mode, the pulse width is increased by a predetermined amount only during that mode.

18. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein during the take right step mode the pulse outputs are selectively output to the left quadriceps channel and the right peroneal channel, while at the same time no stimulus is outputted to the right quadriceps muscle and to the left peroneal nerve, said output to the left quadriceps channels and right peroneal nerve are modified such that during the take right step mode, the pulse width is increased by a predefined amount only during that mode.

19. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein during the take left step mode the pulse outputs are selectively output to the right quadriceps channel and left peroneal channel, while at the same time no stimulus is outputted to the left quadriceps muscle and to the left peroneal nerve;

said output to the right quadriceps and to the left take step mode, the pulse frequency is increased by a predetermined amount only during that mode.

20. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein during the take right step mode the pulse outputs are selectively output to the left quadriceps channel and right peroneal channel, while at the same time no stimulus is outputted to the right quadriceps muscle and to the left peroneal nerve;

said output to the left quadriceps channels and right peroneal nerve are modified such that during the take right step mode, the pulse frequency is increased by a predefined amount only during that mode.

21. An electrical stimulation system adapted for coupling to a patient, said system comprising:

a plurality of electrodes adapted for coupling to locations at the right and left side of a lower part of the body of a patient,

pulse generator means for selectively providing pulse generator means outputs comprising trains of pulses having selectively variable duration and pulse repetition frequency responsive to a control signal;

memory for storing operational instructions and data;

control means for selectively outputting said control signal responsive to said memory and to input commands;

pulse amplifier means for selectively amplifying pulse amplitude and power responsive to said control means and said pulse generator means;

input command means for providing mode input command signals, wherein said control means selectively provides one of a plurality of modes responsive to said input command means; and

,

multiplexer means for providing multiplexer means outputs responsive to selectively multiplexing outputs of said pulse amplifier means and alternatively coupling said multiplexer means output between selected ones of said electrodes responsive to said control means;

wherein said control means switches modes of operation responsive to said input command means to provide a stand mode, a take left step mode, a take right step mode, and a sit down mode;

wherein said electrodes are wired in pairs as channels, one adapted to contact to the right quadriceps muscle, one adapted to contact to the left quadriceps muscle, and one adapted to contact to the area of right and left peroneal nerves;

wherein when a stimulus to the peroneal nerves at the end of a given step is ceased, then a stimulus voltage to the quadriceps of the leg taking that given step is increased in a ramp-like graduated rate versus time.

22. The system as in claim 21, where said ramp-like increase of the stimulus voltage to the quadriceps voltage lasts less than one second.