Method and apparatus for controlling multi-site neurostimulation

Abstract

The present invention improves control of currents in a multi-site direct current neurostimulation system. Precise control incorporates three constant current sources in a system consisting of spinal, polarizing and peripheral circuits. Constant current sources (sinks) are placed on the high side of the peripheral circuit and one sink in series on the low side of the spinal circuit in a four electrode configuration, for maintaining both predetermined currents, and current ratios, as the electrode/skin impedance and body impedance vary over the course of a treatment. Resistive steering is also implemented.

1 . A direct current (DC) neurostimulation system for providing trans-spinal direct current stimulation, forming a spinal circuit at a spinal cord location associated with control of a target body part of a sentient being, and a peripheral circuit for direct current stimulation of the peripheral nerve associated with the control of the target body part, configured to deliver stimulation via electrodes at skin interfaces of said being, comprising:
 said spinal circuit further comprising a spinal stimulation component configured to provide spinal direct current stimulation to the spine;   associated with modulation the target effector organ; a peripheral circuit including a peripheral stimulation component configured to provide peripheral stimulation of the peripheral nerve associated with the target effector organ, said spinal and peripheral circuits configured to provide a resulting polarization circuit defined between a respective anodal electrode and cathodal electrode of the respective spinal and peripheral circuits; said resulting polarization circuit configured to stimulate a descending neuron for regulation of excitability of effected spinal motoneurons and interneurons to control activity of said target body party; and   and a controller component configured to provide a power source for supplying controlled flows of direct current in the spinal, peripheral and polarization circuits to provide stimulation currents to the spinal and peripheral locations associated with control of the target body part, the controller component configured to control the stimulation currents and to provide current steering and current control to the currents at the peripheral and spinal locations.   
     
     
         2 . The system of  claim 1  further comprising a power source and the controller configured to provide said current independent of time-varying loads at the electrode skin interfaces and in the patient's neural pathways connecting between system electrodes. 
     
     
         3 . The system of  claim 2  providing resistive current control in the low voltage spinal return side of the spinal circuit, with current split between polarization and spinal circuits approximately 65/35%+/−10%. 
     
     
         4 . The system of  claim 1  utilizing one of the set of varying, pulsed and constant current DC. 
     
     
         5 . The system of  claim 1  having a power source for supplying controlled flows of direct current in spinal and polarization circuits, providing dynamic current control at the spinal anode and at the spinal cathode in a three-electrode embodiment, at the spinal anode, at the spinal cathode and at the peripheral anode, without the need for resistive current splitting. 
     
     
         6 . The system of  claim 1  having a power source supplying controlled flows of direct current in spinal and polarization circuits, providing dynamic current control at the spinal anode and at the spinal cathode in a four-electrode embodiment, without the need for resistive current splitting. 
     
     
         7 . The system of  claim 1  in a multi-site neurostimulation system with pairing trans-spinal direct current stimulation of the spinal cord (tsDCS) with direct current stimulation of the peripheral nerve (pDCS) leading to the target body part, wherein the controller is further configured to pass low level direct current through the body to achieve therapeutic effects for patients having neurologic conditions. 
     
     
         8 . The system of  claim 7  further configured to provide resistive control in one leg of one of said circuits, configures to split said current between the polarization and spinal circuits 65/35%, ranging about +/−20%. 
     
     
         9 . The system of  claim 8 , further including resistive current control in the low voltage spinal return side of the spinal circuit. 
     
     
         10 . The system of  claim 1 , wherein the controller is configured to provide constant current control independent of the time-varying loads at the electrode skin interfaces and in the patient's neural pathways connecting between system electrodes. 
     
     
         11 . The system of  claim 1  wherein the controller is configured to provide dynamic current control at at least one of the spinal anode in a three electrode embodiment and at the spinal anode and at the peripheral anode in a four electrode embodiment. 
     
     
         12 . The system of  claim 11  further comprising constant current nodes at the peripheral current source and at the spinal current source and at the spinal cathode, wherein the peripheral cathode action follows as it is determined by the control of the peripheral and spinal anodes and spinal cathode. 
     
     
         13 . The system of  claim 11  wherein the controller is further configured to measure current through both the spinal and peripheral anodes in real time, and the polarizing current and the spinal cathode current are one of the set of metered and calculated. 
     
     
         14 . The system of  claim 11  further configured to provide three constant current sources variously to the spinal, polarizing and peripheral circuits, wherein constant current source sinks are placed as follows: one source in series on the “high” side of the spinal circuit, one source in series on the “high” side of the peripheral circuit, and one sink in series on the “low” side of the spinal circuit, in a four-electrode configuration. 
     
     
         15 . The system of  claim 11  further configured to provide three constant current sources variously to the spinal, polarizing and peripheral circuits, wherein constant current source sinks are placed as follows: one source in series on the “high” side of the spinal circuit, one source in series on the “high” side of the peripheral circuit, and one sink in series on the “low” side of the spinal circuit, in a four electrode configuration, wherein the “low” side current sink in the spinal circuit is replaced with a resistor to steer a greater portion of the spinal current to the polarizing circuit. 
     
     
         16 . The system of  claim 1  utilizing one of the set of varying, pulsed and constant current DC.