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. 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).

1 . A method of treating Parkinson's disease (PD) in a patient, comprising:
 identifying a region within the brain of the patient exhibiting dysfunctional neuronal activity caused by PD in the patient;   implanting a stimulation lead within or adjacent to the identified region; and   electrically stimulating, through a plurality of electrodes of the stimulation lead, a population of neuronal tissue to treat PD in the patient, wherein (i) the stimulating repetitively applies, in a time sequence, electrical pulses through different electrodes of the plurality of electrodes to successively stimulate different neuron subpopulations within the population of neuronal tissue; (ii) at least a subset of the applied electrical pulses are provided at a subthreshold level that is sufficiently low to avoid overdriving a substantially majority of neurons of the population to depletion of neurotransmitters in the neurons of the population; and (iii) the applied electrical pulses causes entrainment of neuronal activity within respective subpopulations.   
     
     
         2 . The method of  claim 1  wherein electrical pulses applied at a subthreshold level occur at a pulse amplitude level of 60% to 80% of a difference between an unstimulated resting potential of neurons and a threshold potential for direct stimulated action potential generation. 
     
     
         3 . The method of  claim 1  wherein electrical pulses applied at a subthreshold level occur at a pulse amplitude level of approximately 10% of a difference between an unstimulated resting potential of neurons and a threshold potential for direct stimulated action potential generation. 
     
     
         4 . The method of  claim 1  wherein the identifying comprises conducting an MRI scan of at least a portion of the patient's brain. 
     
     
         5 . The method of  claim 1  wherein electrical pulses, applied to the different neuronal subpopulations, are repeated at a pulse rate with a range of 40 Hz to 200 Hz. 
     
     
         6 . The method of  claim 1  wherein the successively stimulation of different neuron subpopulations within the population of neuronal tissue causes a rotational pattern of stimulation about the plurality of electrodes to occur. 
     
     
         7 . The method of  claim 1  wherein the successively stimulation of different neuron subpopulations within the population of neuronal tissue causes alternating polarities of stimulation in different subpopulations of neurons. 
     
     
         8 . The method of  claim 1  wherein the electrical pulses are biphasic pulses. 
     
     
         9 . The method of  claim 1  wherein the electrical pulses are monophasic pulses.