Methods and apparatus for effectuating a lasting change in a neural-function of a patient

Abstract

The following disclosure describes several methods and apparatus for intracranial electrical stimulation to treat or otherwise effectuate a change in neural-functions of a patient. Several embodiments of methods in accordance with the invention are directed toward enhancing or otherwise inducing a lasting change in neural activity to effectuate a particular neural-function. Such lasting change in neural activity is defined as “neuroplasticity.” The methods in accordance with the invention can be used to treat brain damage (e.g., stroke, trauma, etc.), brain disease (e.g., Alzheimer's, Pick's, Parkinson's, etc.), and/or brain disorders (e.g., epilepsy, depression, etc.). The methods in accordance with the invention can also be used to enhance neural-function of normal, healthy brains (e.g., learning, memory, etc.), or to control sensory functions (e.g., pain). Certain embodiments of methods in accordance with the invention electrically stimulate the brain at a stimulation site where neuroplasticity is occurring. The stimulation site may be different than the region in the brain where neural activity is typically present to perform the particular neural function according to the functional organization of the brain. In one embodiment in which neuroplasticity related to the neural-function occurs in the brain, the method can include identifying the location where such neuroplasticity is present. In an alternative embodiment in which neuroplasticity is not occurring in the brain, an alternative aspect is to induce neuroplasticity at a stimulation site where it is expected to occur. Several embodiments of these methods that are expected to produce a lasting effect on the intended neural activity at the stimulation site use electrical pulses that increase the resting membrane potential of neurons at the stimulation site to a subthreshold level.

1 - 123 . (canceled)  
     
     
         124 . A device for applying electrical stimulation to a region of a brain of a patient, comprising: 
 an implantable pulse generator that includes a signal source carried by an implantable housing;    a signal delivery electrode electrically coupled to the signal source and carried by the housing at a generally fixed lateral location relative to the housing; and    a return electrode, wherein the signal delivery electrode is electrically coupled to the signal source to have a different electrical bias than the return electrode.    
     
     
         125 . The device of  claim 124  wherein the return electrode has a generally fixed lateral location relative to the housing.  
     
     
         126 . The device of  claim 124  wherein the return electrode is carried by the implantable housing.  
     
     
         127 . The device of  claim 124  wherein the housing is configured to be implanted at least partially within the patient's skull, and wherein the device further includes an attachment element carried by the housing and attachable to the skull.  
     
     
         128 . The device of  claim 124  wherein the implantable pulse generator is programmed to provide electrical signals to the signal delivery electrode at subthreshold levels.  
     
     
         129 . The device of  claim 124  wherein the signal delivery electrode projects from the housing in a direction generally normal to the housing.  
     
     
         130 . The device of  claim 124  wherein the signal delivery electrode is one of a plurality of signal delivery electrodes.  
     
     
         131 . The device of  claim 124 , further comprising an external controller operatively coupleable to the pulse generator via a communication link.  
     
     
         132 . The device of  claim 124  wherein the signal delivery electrode is movable in a direction generally normal to the housing to apply a force to adjacent tissue when the housing is implanted.  
     
     
         133 . The device of  claim 124  wherein the housing includes a forcing element to which the signal delivery electrode is coupled, the forcing element being positioned to apply a force to the signal delivery electrode in a direction generally normal to the housing.  
     
     
         134 . The device of  claim 124  wherein the signal delivery electrode has a pin shape and is positioned to extend into brain tissue of the patient.  
     
     
         135 . The device of  claim 124  wherein the signal delivery electrode has a generally blunt shape and is positioned to bear against at least one of a dura mater and a pia mater of the patient.  
     
     
         136 . A device for applying electrical stimulation to a region of a brain of a patient, comprising: 
 an implantable pulse generator that includes a signal source carried by an implantable housing;    a first electrode carried by the housing and having a generally fixed lateral location relative to the housing;    a second electrode carried by the housing and having a generally fixed lateral location relative to the housing, wherein the first and second electrodes have different electrical biases.    
     
     
         137 . The device of  claim 136  wherein the first electrode includes a signal delivery electrode and the second electrode includes a return electrode.  
     
     
         138 . The device of  claim 136  wherein the first electrode includes one of a plurality of signal delivery electrodes.  
     
     
         139 . The device of  claim 136  wherein the signal source includes a pulse transmitter coupled to a power supply.  
     
     
         140 . The device of  claim 136  wherein the housing is configured to be implanted at least partially within the patient's skull, and wherein the device further includes an attachment element carried by the housing and attachable to the skull.  
     
     
         141 . The device of  claim 136  wherein the implantable pulse generator is programmed to provide electrical signals at subthreshold levels.  
     
     
         142 . The device of  claim 136  wherein the first electrode projects from the housing in a direction generally normal to the housing.  
     
     
         143 . The device of  claim 136 , further comprising an external controller operatively coupleable to the pulse generator via a communication link.  
     
     
         144 . The device of  claim 136  wherein the first electrode is movable in a direction generally normal to the housing to apply a force to adjacent tissue when the housing is implanted.  
     
     
         145 . The device of  claim 136  wherein the housing includes a forcing element to which the first electrode is coupled, the forcing element being positioned to apply a force to the first electrode in a direction generally normal to the housing.  
     
     
         146 . The device of  claim 136  wherein the first electrode has a pin shape and is positioned to extend into brain tissue of the patient.  
     
     
         147 . The device of  claim 136  wherein the first electrode has a generally blunt shape and is positioned to bear against at least one of a dura mater and a pia mater of the patient.