Dipole electrical stimulation employing direct current for recovery from spinal cord injury

Abstract

A system and method to treat neuromuscular conditions, including spinal cord injury, by what is characterized as dipole (two point) cortico-muscular stimulation. Two-point stimulation, with oppositely charged electrodes, allows pulsed, direct current to pass through the cortico-muscular pathway. The electrodes are placed on nerves, muscles, or a combination of both, that are on opposite sides of the spinal column, forming a current that passes across the spinal column. Further, an active electrode can be placed on the spinal column and a reference electrode can be placed outside the central nervous system. These methods improve functional recovery of the motor pathway.

1 - 65 . (canceled) 
     
     
         66 . A system to improve neuromuscular condition of a vertebrate being, comprising:
 a DC stimulator having a direct current stimulator circuit configured for providing trans-spinal direct current stimulation, having positive and negative connections to a DC source for defining a first point and a second point along a neural pathway of interest related to activity of a body part of a vertebrate being, said stimulator circuit being further configured to provide DC current flow between said positive and negative connections for stimulation of said neural pathway between said points, said stimulation including stimulation across a spinal location on said neural pathway between said points, said spinal location being associated with said activity, said second point on said neural pathway being distal to said spinal location, said stimulation for improving said activity.   
     
     
         67 . The system of  claim 66 , wherein said stimulator circuit is further configured to stimulate a muscle of interest on said neural pathway to improve muscle twitch force and spinal cord response related to said activity, said stimulator circuit further configured to provide one of said first point and said second point as positive and the other as negative to set the direction of said current flow. 
     
     
         68 . The system of  claim 67 , wherein said stimulator circuit is further configured to provide said current flow between said first point and said second point, including through said spinal column at said spinal location, wherein said first point is associated with one of said motor cortex and a muscle of said being associated with said spinal location, and wherein said second point is contralateral to said first point on said being, and wherein said first point is either positive or negative according to the action of said body part to be stimulated. 
     
     
         69 . The system of  claim 66 , wherein said direct current is pulsed and wherein one of said points is associated with a motor cortex location associated with activity of said body part and wherein the other one of said points is associated with activity of a muscle associated with said body part. 
     
     
         70 . The system of  claim 69 , wherein said stimulation circuit is further configured wherein said stimulation between said two points is for treating a neuromuscular condition along a cortico-muscular pathway of said being, wherein said first point is associated with a motor cortex of said being and said second point is associated with activity of a muscle associated with said body part, and configured to provide said points oppositely charged as either one of either positive and negative, for passing said direct current flow along said cortico-muscular pathway, and further configured to stimulate recovery of said body part activity according to the direction of said current flow from said positive to said negative points. 
     
     
         71 . The system of  claim 70 , wherein said stimulation is selected from the set of signal-types including pulsed, constant current and constant voltage. 
     
     
         72 . The system of  claim 71 , wherein a magnitude and polarity of at least one said stimulation is computer-controlled. 
     
     
         73 . The system of  claim 66 , wherein said DC stimulator is configured to apply said stimulation as a pulsed direct current between said first point and said second point on said neural pathway, said second point being distal to said spinal location at a location outside of said central nervous system. 
     
     
         74 . The system of  claim 73 , wherein said DC stimulator is configured to apply said stimulation between said first point and said second point at a location outside of said central nervous system, including distal locations at the abdominal and pelvic regions. 
     
     
         75 . The system of  claim 66 , wherein said stimulator circuit is configured to apply said stimulation across said spinal location and configured to apply additional electrical stimulation at least to one of said motor cortex and a peripheral nerve serving at least one muscle associated with said body part, to enhance neuromuscular performance of said being. 
     
     
         76 . The system of  claim 66 , wherein said DC stimulator includes a first stimulator unit and further comprising at least one additional stimulator unit, said units cooperating either synchronously and asynchronously to stimulate said pathway and said spinal location, said additional stimulation unit providing stimulation at least at one of said motor cortex and said muscular location. 
     
     
         77 . The system of  claim 76 , further configured wherein electrical pulses are applied to said spinal column via an active spinal electrode, with at least one spinal reference electrode applied to said second point outside the central nervous system, for trans-spinal direct current stimulation of said spinal location, further including an additional stimulator for stimulation of at least one of said motor cortex and a peripheral nerve associated with at least one muscle to enhance neuromuscular performance of said being. 
     
     
         78 . The system of  claim 76 , wherein at least one of said stimulator units is configured to apply electrical pulses to said spinal location, wherein said electrical pulses are applied either alone or in combination with additional electrical pulses applied to one or both of said motor cortex and at least one said nerve, synchronously or asynchronously, to enhance neuromuscular performance of said being. 
     
     
         79 . The system of  claim 78 , wherein at least one of said stimulator units is configured to define an active electrode at said first point and a reference electrode at said second point, said first point is defined at a motor cortex location, wherein said second point is defined at a contralateral muscle, said stimulation configured to improve muscle twitch force and spinal cord responses of said being. 
     
     
         80 . The system of  claim 79 , wherein one said stimulator unit is configured to provide an additional electrical stimulus to the motor cortex or to a muscle of said being, said stimulator circuit being configured to coordinate the passing of said current flow between said first point and second point with application of said additional electrical stimulus including at least one electrical pulse, applied synchronously or asynchronously with the application of said stimulation of said spinal location. 
     
     
         81 . The system of  claim 79 , further comprising one said stimulator unit configured to provide electrical stimulus to the motor cortex and one said stimulator unit configured to provide electrical stimulus to said muscle, wherein said stimulator circuit is configured to coordinate the passing of said current flow between said first point and second point with application stimulus of said additional and said other electrical stimulus. 
     
     
         82 . The system of  claim 81 , further comprising a configuration wherein at least one said electrical stimulus of said motor cortex and muscle includes at least one electrical pulse applied synchronously or asynchronously with said stimulation of said spinal location. 
     
     
         83 . The system of  claim 76 , wherein said stimulator circuit is provided as a first stimulator unit and further comprising at least one additional stimulator unit, said units cooperating either synchronously and asynchronously to stimulate said pathway, said additional stimulation unit providing stimulation at least at one of said motor cortex and said muscular location. 
     
     
         84 . The system of  claim 76 , wherein said DC stimulator is configured to apply a plurality of pulses between said first point and said second point. 
     
     
         85 . The system of  claim 84 , further including a plurality of pulses having a pulse duration from 0.5 ms to 5 ms. 
     
     
         86 . The system of  claim 84 , wherein said DC stimulator is configured to apply between said first point and said second point a plurality of pulses. 
     
     
         87 . The system of  claim 76 , wherein said DC stimulator is configured to apply a plurality of pulses between said first point and said second point, wherein said plurality of pulses has a frequency from 0.5 Hz to 5 Hz. 
     
     
         88 . The system of  claim 66 , further configured to provide a prompt to move a limb coordinated with application of said stimulation to said spinal location, wherein said prompt is selected from the set of an aural prompt, a visual prompt, and a tactile prompt, wherein said prompt is provided manually or by a system unit configured to generate the prompt in synchronization with the stimulation of said spinal location. 
     
     
         89 . The system of  claim 79 , wherein said DC stimulator is configured including a plurality of stimulator units to provide a plurality of stimulations synchronously or asynchronously with said stimulation at said spinal location, including at least one stimulation of a muscle of said being. 
     
     
         90 . The system of  claim 89 , wherein said DC stimulator is configured to provide an additional stimulation current flow along an additional neural path that crosses said the spinal column to an additional muscle of said being. 
     
     
         91 . The system of  claim 66 , wherein said first and second point locations are selected from motor cortex and muscle locations and said activity is activity of a muscle associated with said spinal location. 
     
     
         92 . The system of  claim 66 , further comprising a stimulation circuit configured to stimulate a motor cortex location on a first side of said spinal cord with said reference electrode at a location on the other side of said spinal location distal to said motor cortex location. 
     
     
         93 . The system of  claim 90 , wherein said first and second point locations are selected from motor cortex and muscle locations and said activity is activity of a muscle associated with said spinal location. 
     
     
         94 . The system of  claim 73 , wherein said stimulation circuit is configured to stimulate a contralateral muscle of said being wherein said pulsed direct current is provided along core conductors of said neural pathway from said spinal location to said muscle, for improving spinal cord responses and muscle force in said being. 
     
     
         95 . The system of  claim 73 , wherein said stimulation circuit is further configured for improving spinal cord responses and muscle force in said being, and includes a reference electrode connection configured to stimulate a contralateral muscle of said being wherein said pulsed direct current is provided a between a first point proximal to said spinal location along said neural pathway to a second point associated with said contralateral muscle. 
     
     
         96 . The system of  claim 95 , wherein said system is configured to include at least one active electrode to be placed at, or in proximity to, said first point located at the central nerve system of said being; at least one reference electrode to be placed at, or in proximity to, a second point that is located outside the central nervous system, further comprising a stimulator unit configured to generate at least one electrical stimulation waveform for said electrodes, wherein the system is configured to form a current path through a stimulation pathway across the spinal column of said being between the first point and the second point for delivery of said waveform through said electrodes. 
     
     
         97 . The system of  claim 66 , further comprising a plurality of stimulator units, with at least one unit configured to generate at least one electrical stimulation waveform to be applied across said spinal location, and configured to synchronize one said stimulator unit and another said stimulator unit to provide stimulation simultaneously to said spinal location and to another location of either muscle or cortex of said being. 
     
     
         98 . A system for stimulation of a neurological condition associated with a target body part of a vertebrate being, comprising:
 a stimulator configured for delivering polarizing DC spinal stimulation current across a spinal stimulation point associated with a spinal location of a vertebrate being for innervating said spinal location and for stimulation of a connecting neural pathway between said spinal location and a distal reference point at a distal location of the being, said spinal location associated with regulation of neural activity of a target body part of the being, the target body part being in neural communication with said spinal location via said neural pathway, and said stimulator further configured to deliver said DC spinal stimulation current to said spinal location as one of the set of excitatory and inhibitory stimulations, said stimulator being configured to provide directional current flow along said neural pathway, wherein said one of said excitatory and inhibitory stimulations is selected according to the direction of flow of said delivered DC stimulation current, for controlling said neural activity.   
     
     
         99 . The system of  claim 98  wherein said stimulator is configured with positive and negative poles, said stimulator further configured to enable said DC stimulation current flow between said positive and negative poles, wherein said current flow is excitatory at said spinal location when said spinal location is coupled to said negative pole and said reference location is coupled to said positive pole. 
     
     
         100 . The system of  claim 98  wherein said stimulator is configured with positive and negative poles, said stimulator further configured to enable said DC stimulation current flow between said positive and negative poles, wherein said current flow is inhibitory at said spinal location when said spinal location is coupled to said positive pole and said reference location is coupled to said negative pole. 
     
     
         101 . The system of  claim 100  wherein said stimulator is configured to depress and excite said neural activity according to one of said anode and cathode being at said spinal location and the other being at said distal location. 
     
     
         102 . The system of  claim 101  wherein said stimulator configured to inhibit neural activity on said neural pathway by application of anodal stimulation at said spinal location. 
     
     
         103 . The system of  claim 98  wherein said stimulator includes a computer circuit wherein said DC stimulation current strength and polarity are computer-controlled. 
     
     
         104 . The system of  claim 98  further comprising a cortical stimulator having an output for delivery of pulsed stimulation current at a motor cortex location of the being on said neural pathway associated with stimulation of the target body part; further comprising a muscle stimulator having an output for delivery of pulsed stimulation current at a location on the neural pathway associated with activity of at a target muscle at said target body part; and said stimulator further configured to control application of each of said spinal, cortical and muscle stimulation current, either synchronously or asynchronously, to said neural pathway between said cortical stimulator and said muscle stimulator. 
     
     
         105 . The system of  claim 104  wherein said stimulator is configured to provide trans-spinal direct current stimulation across said spinal location to influence modulation of motor cortex activity at the spinal level, wherein said modulation is controlled depending on the direction and intensity of the applied spinal stimulation. 
     
     
         106 . The system of  claim 104  wherein the muscle stimulator is configured to deliver negative monopolar current to stimulate the target muscle synchronously with the pulsed polarizing stimulation current. 
     
     
         107 . The system of  claim 105  wherein the cortical stimulator is configured to deliver pulsed monopolar current to the motor cortex synchronously with the pulsed polarizing stimulation current at the spinal location. 
     
     
         108 . The system of  claim 107  wherein the cortical stimulator is configured to supply repetitive stimulations of pulsed DC current. 
     
     
         109 . The system of  claim 98  wherein the spinal stimulator further includes lead wires for respective coupling said spinal point and said distal reference point with respective first reference electrodes configured to be placed at a left anterior superior iliac spine and a second of the pair configured to be placed at a right anterior superior iliac spine of the being. 
     
     
         110 . The system of  claim 104  wherein at least one of said stimulators is configured to provide at least one stimulation signal waveform selected as any of continuous, constant voltage, ramped, pulsed, and variable. 
     
     
         111 . The system of  claim 110  wherein at least one of said stimulators is configured to produce a plurality of pulses having a duration from 0.5 ms to 5 ms. 
     
     
         112 . The system of  claim 110  wherein at least one of said stimulators is configured to pass a plurality of pulses having a frequency from 0.5 Hz to 5 Hz. 
     
     
         113 . The system of  claim 104  wherein said stimulator is configured to initiate a prompt to move a limb of the being, either synchronously or asynchronously with delivering said DC polarizing stimulation current across said spinal location. 
     
     
         114 . The system of  claim 113  wherein said stimulator is configured to initiate an aural prompt, a visual prompt, or a tactile prompt. 
     
     
         115 . The system of  claim 98  further comprising a digital-to-analog converter (DAC) to provide analog output to at least one of said stimulators. 
     
     
         116 . The system of claim  120  wherein said DAC is configured to provide at least one of constant DC voltage levels and a DC waveform under software control. 
     
     
         117 . The system of  claim 79  wherein said stimulator further includes electrodes for application of at least one said stimulation configured as one of the set of topically, underneath a skin surface, and by surgical implantation. 
     
     
         118 . The system of  claim 66  wherein said stimulation circuit is further configured to provide one said point as an anodal point and the other said point as a cathodal point of said circuit, and further configured to provide said stimulation current flow from said anodal point to said cathodal point for stimulating said spinal location.