Method and apparatus for altering neural tissue function

Abstract

A method and apparatus for altering a function of neural tissue in a patient. An electromagnetic signal is applied to the neural tissue through an electrode. The electromagnetic signal has a frequency component above the physiological stimulation frequency range and an intensity sufficient to product an alteration of the neural tissue, the alteration causing the patient to experience a reduction in pain, and a waveform that prevents lethal temperature elecation of the neural tissue during application of the electromagnetic signal to the neural tissue.

1. A method for sustained neural function modification in a patient comprising:
 generating an amplitude modulated signal having at least one frequency component above a physiologic stimulation frequency range; and  
 applying the amplitude modulated signal to selected neural tissue in the patient for altering a function of the tissue without heating the tissue to temperatures lethal to the tissue, wherein said amplitude modulated signal has a peak voltage, said peak voltage being sufficient to alter the function of the tissue in the patient, wherein the function remains altered for a given period of time after application of the signal to the tissue is ceased.  
 
     
     
       2. The method of  claim 1  wherein altering the function of the tissue reduces pain experienced by the patient. 
     
     
       3. The method of  claim 1  wherein altering the function of the tissue reduces pain by tremor experienced by the patient. 
     
     
       4. The method of  claim 1  wherein altering the function of the tissue reduces symptoms of Parkinson's disease experienced by the patient. 
     
     
       5. The method of  claim 1  wherein altering the function of the tissue reduces symptoms of spasticity experienced by the patient. 
     
     
       6. The method of  claim 1  wherein altering the function of the tissue reduces symptoms of mood disorder experienced by the patient. 
     
     
       7. The method of  claim 1  wherein altering the function of the tissue reduces symptoms of epilepsy experienced by the patient. 
     
     
       8. The method of  claim 1  wherein altering the function of the tissue alleviates motor disfunction. 
     
     
       9. The method of  claim 1  wherein the at least the frequency component of the amplitude modulated signal alters the function of the tissue. 
     
     
       10. The method of  claim 1  wherein applying the amplitude modulated signal to the tissue comprises engaging the tissue with an electrode coupled with a signal generator generating the amplitude modulated signal. 
     
     
       11. The method of  claim 1  wherein temperatures lethal to the tissue are greater than 45° C. 
     
     
       12. The method of  claim 1  wherein the at least one frequency component has a frequency greater than 300 Hz. 
     
     
       13. An apparatus for sustained alteration of a function of selected neural tissue in a patient comprising
 a signal generator and an electrode coupled to the signal generator, said signal generator being adapted to generate an amplitude modulated signal having at least one frequency component above a physiologic stimulation frequency range, said electrode being adapted to apply the signal to the tissue, wherein application of the amplitude modulated signal to the tissue alters a function of the tissue while inhibiting heating of the tissue to temperatures lethal to the tissue, wherein said amplitude modulated signal has a peak voltage, said peak voltage being sufficient to alter the function of the tissue in the patient, and wherein alteration of the function of the tissue persists even after application of the signal to the tissue ceases.  
 
     
     
       14. The apparatus of  claim 13  wherein altering the function of the tissue reduces pain experienced by the patient. 
     
     
       15. The apparatus of  claim 13  wherein altering the function of the tissue causes the patient to experience a reduction in pain by tremor. 
     
     
       16. The apparatus of  claim 13  wherein altering the function of the tissue causes the patient to experience reduced symptoms of Parkinson's disease. 
     
     
       17. The apparatus of  claim 13  wherein altering the function of the tissue causes the patient to experience a reduced symptoms of spasticity. 
     
     
       18. The apparatus of  claim 13  wherein altering the function of the tissue causes the patient to experience a reduced symptoms of mood disorder. 
     
     
       19. The apparatus of  claim 13  wherein altering the function of the tissue causes the patient to experience a reduced symptoms of epilepsy. 
     
     
       20. The apparatus of  claim 13  wherein altering the function of the tissue alleviates motor disfunction. 
     
     
       21. The apparatus of  claim 13  wherein the at least one frequency component of the amplitude modulated signal alters the function of the tissue. 
     
     
       22. A method for lasting modification of neural tissue function in a patient comprising:
 placing an electrode in or near selected neural tissue of the patient;  
 generating an amplitude modulated signal and transmitting the signal to the electrode, said signal having at least one frequency component above a physiologic stimulating frequency range for alteration of a function of the tissue without heating the tissue to temperatures lethal to the tissue, wherein said amplitude modulated signal has a peak voltage being sufficient to alter the function of the tissue in the patient, said alteration being sustained even after transmission of the signal to the electrode ceases.  
 
     
     
       23. The method of  claim 22  wherein altering the function of the tissue reduces pain experienced by the patient. 
     
     
       24. The method of  claim 22  wherein altering the function of the tissue causes the patient to experience a reduction in pain by tremor. 
     
     
       25. The method of  claim 22  wherein altering the function of the tissue causes the patient to experience reduced symptoms of Parkinson's disease. 
     
     
       26. The method of  claim 22  wherein altering the function of the tissue causes the patient to experience a reduced symptoms of spasticity. 
     
     
       27. The method of  claim 22  wherein altering the function of the tissue causes the patient to experience a reduced symptoms of mood disorder. 
     
     
       28. The method of  claim 22  wherein altering the function of the tissue causes the patient to experience a reduced symptoms of epilepsy. 
     
     
       29. The method of  claim 22  wherein altering the function of the tissue alleviates motor disfunction. 
     
     
       30. The method of  claim 22  wherein the at least one frequency component of the amplitude modulated signal alters the function of the tissue. 
     
     
       31. The method of  claim 22  wherein temperatures lethal to the tissue are greater than 45° C. 
     
     
       32. The method of  claim 22  wherein the at least one frequency component has a frequency greater than 300 Hz. 
     
     
       33. A method for sustained neural function modification in a patient comprising:
   generating interrupted radiofrequency waveforms having predetermined time periods of on - time bursts of radiofrequency output of a first predetermined duration followed by relatively substantial off - time periods of very low output at a second predetermined duration; and        applying the interrupted radiofrequency waveforms to selected neural tissue in the patient for a predetermined treatment time sufficient to result in alteration of a function of the tissue without heating the tissue to temperatures lethal to the tissue, wherein the interrupted radiofrequency waveforms have a peak voltage sufficient to result in said alteration, wherein the function remains altered for a given period of time after application of the signal to the tissue is ceased.     
     
     
       34. The method of  claim 33 , wherein altering the function of the tissue reduces symptoms experienced by the patient selected from the group consisting of pain, tremor, Parkinson's disease, spasticity, mood disorder, epilepsy, and motor dysfunction. 
     
     
       35. The method of  claim 33 , wherein the step of applying the interrupted radiofrequency waveforms to the tissue includes engaging the tissue with an electrode coupled with a signal generator. 
     
     
       36. The method of  claim 33 , wherein the generating step includes having a ratio of on- time bursts of radiofrequency output to off - time bursts of approximately two percent.   
     
     
       37. An apparatus for sustained alteration of a function of selected neural tissue in a patient comprising:
   a signal generator which generates interrupted radiofrequency waveforms having predetermined time periods of on - time bursts of radiofrequency output of a first predetermined duration followed by relatively substantial off - time periods of very low output at a second predetermined duration,        an electrode coupled to the generator and being adapted to apply the interrupted radiofrequency waveforms to the tissue, wherein application of the interrupted radiofrequency waveforms to the tissue alters a function of the tissue while inhibiting heating of the tissue to temperatures lethal to the tissue, wherein the interrupted radiofrequency waveforms have a peak voltage, said peak voltage being sufficient to result in said alteration, and wherein alteration of the function of the tissue persists even after application of the signal to the tissue ceases.     
     
     
       38. The apparatus of  claim 37 , wherein altering the function of the tissue reduces symptoms experienced by the patient selected from the group consisting of pain, tremor, Parkinson's disease, spasticity, mood disorder, epilepsy, and motor dysfunction. 
     
     
       39. The apparatus of  claim 37 , wherein the generator is adapted to apply the interrupted radiofrequency waveforms to the tissue in a ratio of on- time bursts of radiofrequency output to off - time bursts of approximately two percent.   
     
     
       40. An apparatus for sustained alteration of a function of selected neural tissue in a patient comprising:
   a signal generator which generates interrupted radiofrequency waveforms having predetermined time periods of on - time bursts of radiofrequency output of a first predetermined duration followed by relatively substantial off - time periods of very low output at a second predetermined duration;        an electrode coupled to the generator and being adapted to apply the interrupted radiofrequency waveforms to the tissue by being surgically inserted in or on the patient, wherein application of the interrupted radiofrequency waveforms to the tissue alters a function of the tissue while inhibiting heating of the tissue to temperatures lethal to the tissue, and wherein alteration of the function of the tissue persists even after application of the signal to the tissue ceases, and wherein the interrupted radiofrequency waveforms have a peak voltage sufficient to alter the neural tissue, and wherein said peak voltage is in a range that includes tens of volts.