Methods and apparatus for effectuating a 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 - 33 . (Cancelled)  
     
     
         34 . A method for recovering a neural-function affected by a stroke, comprising: 
 implanting an electrode at a cortical stimulation site selected to promote recovery of the affected neural-function, the cortical stimulation site being at least proximate to the cortex; and    electrically stimulating the cortical stimulation site by passing an electrical current through the electrode.    
     
     
         35 . The method of  claim 34  wherein implanting the electrode comprises placing the electrode proximate to the dura mater at the cortex.  
     
     
         36 . The method of  claim 34  wherein implanting the electrode comprises placing the electrode in contact with the dura mater at the cortex.  
     
     
         37 . The method of  claim 34  wherein implanting the electrode comprises placing the electrode proximate to the pia mater at the cortex.  
     
     
         38 . The method of  claim 34  wherein implanting the electrode comprises placing the electrode in contact with the pia mater at the cortex.  
     
     
         39 . The method of  claim 34  wherein implanting the electrode comprises positioning the electrode at the supplementary motor cortex anterior to a location of the stroke.  
     
     
         40 . The method of  claim 34  wherein electrically stimulating the cortical stimulation site comprises passing an anodic current through the electrode.  
     
     
         41 . The method of  claim 34  wherein electrically stimulating the cortical stimulation site comprises passing a cathodic current through the electrode.  
     
     
         42 . The method of  claim 34  wherein applying electrical stimulation comprises applying a signal having a voltage of approximately 50 mV to 5V directly to the cortex at the cortical stimulation site.  
     
     
         43 . The method of  claim 34  wherein applying electrical stimulation comprises applying a signal having a voltage effective to raise an expected resting potential of a population of neurons at the stimulation site by at least approximately 10% of a difference between the expected resting potential and an action potential for the population of neurons.  
     
     
         44 . The method of  claim 34  wherein applying electrical stimulation comprises applying a signal having a voltage effective to raise an expected resting potential of a population of neurons at the stimulation site by at least approximately 60% of a difference between the expected resting potential and an action potential for the population of neurons.  
     
     
         45 . The method of  claim 34  wherein applying electrical stimulation comprises applying a signal having a voltage effective to raise an expected resting potential of a population of neurons at the stimulation site by at least approximately 10-80% of a difference between the expected resting potential and an action potential for the population of neurons.  
     
     
         46 . The method of  claim 34  wherein applying electrical stimulation comprises applying a signal having a frequency of approximately 40-200 HZ.  
     
     
         47 . The method of  claim 34  wherein applying electrical stimulation comprises applying a signal having a frequency of approximately 50 HZ.  
     
     
         48 . A method for recovering a neural-function affected by a stroke, comprising: 
 implanting an electrode in a patient at a cortical stimulation site selected to promote recovery of the affected neural-function, the cortical stimulation site being at least proximate to the cortex;    electrically stimulating the cortical stimulation site by passing an electrical current through the electrode; and    performing behavioral therapy on the patient.    
     
     
         49 . The method of  claim 48  wherein the affected neural-function is related to a body part impaired by the stroke, and performing behavioral therapy on the patient comprises moving the body part.  
     
     
         50 . The method of  claim 48  wherein the affected neural-function is related to a body part impaired by the stroke, and performing behavioral therapy on the patient comprises performing physical therapy on the body part.  
     
     
         51 . A method for recovering a neural-function affected by a stroke, comprising: 
 implanting an electrode at a cortical stimulation site selected to promote recovery of the affected neural-function, the cortical stimulation site being at least proximate to the cortex;    electrically stimulating the cortical stimulation site by passing an electrical current through the electrode; and    performing an adjuctive therapy on a body part to which the affected neural-function is related.    
     
     
         52 . The method of  claim 51  wherein the adjunctive therapy comprises electrically stimulating the body part.  
     
     
         53 . The method of  claim 51  wherein the adjunctive therapy comprises electrically stimulating the body part while electrically stimulating the cortical stimulation site.  
     
     
         54 . The method of  claim 51  wherein the adjuctive therapy comprises moving the body part.  
     
     
         55 . The method of  claim 51  wherein the adjuctive therapy comprises moving the body part while electrically stimulating the cortical stimulation site.  
     
     
         56 . The method of  claim 51  wherein implanting the electrode comprises placing the electrode proximate to the dura mater at the cortex.  
     
     
         57 . The method of  claim 51  wherein implanting the electrode comprises placing the electrode in contact with the dura mater at the cortex.  
     
     
         58 . The method of  claim 51  wherein implanting the electrode comprises placing the electrode proximate to the pia mater at the cortex.  
     
     
         59 . The method of  claim 51  wherein implanting the electrode comprises placing the electrode in contact with the pia mater at the cortex.  
     
     
         60 . The method of  claim 51  wherein implanting the electrode comprises positioning the electrode at the supplementary motor cortex anterior to a location of the stroke.  
     
     
         61 . The method of  claim 51  wherein electrically stimulating the cortical stimulation site comprises passing an anodic current through the electrode.  
     
     
         62 . The method of  claim 51  wherein electrically stimulating the cortical stimulation site comprises passing a cathodic current through the electrode.  
     
     
         63 . The method of  claim 51  wherein applying electrical stimulation comprises applying a signal having a voltage of approximately 50 mV to 5V directly to the cortex at the cortical stimulation site.  
     
     
         64 . The method of  claim 51  wherein applying electrical stimulation comprises applying a signal having a voltage effective to raise an expected resting potential of a population of neurons at the stimulation site by at least approximately 10% of a difference between the expected resting potential and an action potential for the population of neurons.  
     
     
         65 . The method of  claim 51  wherein applying electrical stimulation comprises applying a signal having a voltage effective to raise an expected resting potential of a population of neurons at the stimulation site by at least approximately 60% of a difference between the expected resting potential and an action potential for the population of neurons.  
     
     
         66 . The method of  claim 51  wherein applying electrical stimulation comprises applying a signal having a voltage effective to raise an expected resting potential of a population of neurons at the stimulation site by at least approximately 10-80% of a difference between the expected resting potential and an action potential for the population of neurons.  
     
     
         67 . The method of  claim 51  wherein applying electrical stimulation comprises applying a signal having a frequency of approximately 40-200 HZ.  
     
     
         68 . The method of  claim 51  wherein applying electrical stimulation comprises applying a signal having a frequency of approximately 50 HZ.