Nervous tissue stimulation device and method

Abstract

A method using a precisely controlled, computer programmable stimulus for neuroselective tissue stimulation that does not leave a sufficient voltage or electrical artifact on the tissue being stimulated that would interfere or prevent a monitoring system from recording the physiological response is utilized to evaluate the physiological conduction of the tissue being studied. A computer controls both the waveform, duration and intensity of the stimulus. An output trigger to the nerve response recording component controls the timing of its operation. A neuroselective nervous tissue response latency and amplitude may be determined. The computer controlled stimulus may also be administered for therapeutic purposes.

1 . An apparatus with computer control used in neuroselectively evoking responses from nervous tissue using electronic or electromagnetic stimulation that does not leave a sufficient voltage or electrical artifact on the tissue being stimulated that would interfere or prevent a monitoring system from recording the physiological response.  
     
     
         2 . The apparatus in  claim 1  may be recorded by a nerve response recording component including an output trigger to the nerve response recording component.  
     
     
         3 . An apparatus in  claim 1  employs programmable circuitry to generate the output wave form signal used to stimulate the nervous tissue.  
     
     
         4 . The apparatus in  claim 1  employs programmable circuitry to generate the output wave form signal used to stimulate the nervous tissue to be a 180° or a 360° sinusoid waveform stimulus.  
     
     
         5 . The apparatus may be used in conjunction or as a component of currently commercially available NCV, nervous tissue monitor or the Current Perception Threshold (CPT) apparatus described in Katims U.S. Pat. No. 5,806,522.  
     
     
         6 . The apparatus in  claim 1  may be monitored, programed and controlled by an external computer.  
     
     
         7 . The apparatus of  claim 1  using quartz crystal timing.  
     
     
         8 . The apparatus of  claim 1  generating a constant current output.  
     
     
         9 . The apparatus of the present invention provides a neuroselective nervous tissue stimulator apparatus that may be used with the response recording component of currently commercially available NCV devices or may be included as a component of an NCV device with a response recording component.  
     
     
         10 . The apparatus in  claim 1  may employ programmable circuitry to generate the output waveform stimulus used to stimulate the nervous tissue with rapidly increasing intensities and therefore rapidly depolarize the nervous tissue to permit the preferential stimulation of larger diameter nerve fibers or more responsive nervous tissue.  
     
     
         11 . The apparatus in  claim 1  may employ programmable circuitry to generate the output wave form stimulus used to stimulate the nervous tissue with slowly increasing intensities and therefore slowly depolarizing the nervous tissue. This slowly depolarizing stimulus permits the preferential stimulation of smaller diameter nerve fibers of less reactive nerve tissue. Examples of such wave forms include a 5 Hz sinusoid, triangular or elliptical shapes.  
     
     
         12 . The apparatus in  claim 1  may provide an output signal that may be repeatedly administered to permit a response monitoring system to conduct a signal averaging analysis.  
     
     
         13 . The apparatus in  claim 1  may provide an output signal that may be delivered an inductor to generate magnetic fields for electromagnetic stimulation.  
     
     
         14 . The method of using 180 or 360 degree sinewave electrical or electromagnetic stimulation of various frequencies to obtain painless and neuroselective stimulation to evoke nervous tissue responses which may be monitored by response monitoring equipment to determine response latencies and amplitudes.  
     
     
         15 . The method of using a slowly depolarizing stimulus waveform of electrical or electromagnetic stimulation to selectively evoke small fiber or slowly responsive nervous tissue responses or a rapidly depolarizing stimulus waveform of electrical or electromagnetic stimulation to selectively evoke large fiber or rapidly responsive nervous tissue responses where the stimulus does not leave a voltage potential on the tissue being stimulated that could interfere wit a nervous tissue response monitoring system.  
     
     
         16 . The method of claims  8  or  9  that may be applied to human, animal or isolated nervous tissue.  
     
     
         17 . The method of using neuroselective stimulation in order to obtain relatively painless nerve conduction velocity and amplitude measurements.  
     
     
         18 . The method of using neuroselective stimulation in order to permit discrete nervous tissue stimulation that does not interfere with nervous tissue response monitoring equipment where nervous tissue responses may need to be monitored such as for monitoring therapeutic interventions, including in situ monitoring of nerve responses for evaluating the response to a therapeutic intervention,  
     
     
         19 . The method of using discrete neuroselective stimulation for therapeutic purposes including nervous tissue stimulation that does not interfere with nervous tissue response monitoring equipment for pain relief including spinal cord stimulation, prosthetic nerve stimulation, therapeutic nervous tissue stimulation including the purposes of augmenting or attenuating normal or impaired nerve function.