Method of assessing neural function

1. A method of quantitatively identifying a difference in nerve function, the method comprising:

generating a first electrical stimulus;

receiving a first mechanomyography signal from an accelerometer in mechanical communication with a muscle of a subject, the first mechanomyography signal indicative of a mechanical muscle response induced by the first electrical stimulus;

recording a maximum amplitude of the received, first mechanomyography signal;

generating a second electrical stimulus receiving a second mechanomyography signal from the accelerometer, the second mechanomyography signal indicative of a mechanical muscle response induced by the second electrical stimulus;

recording a maximum amplitude of the received, second mechanomyography signal;

identifying a difference in nerve function if the maximum amplitude of the received, second mechanomyography signal is different than the maximum amplitude of the received, first mechanomyography signal;

wherein the first electrical stimulus and the second electrical stimulus have a common current; and

wherein the difference in nerve function is attributable to a surgical procedure.

2. The method of claim 1 , further comprising providing each of the respective first and second electrical stimuli to the distal end portion of a stimulator that is configured to extend within an intracorporeal treatment area of the subject.

3. The method of claim 1 , wherein the accelerometer is disposed external to the subject.

4. The method of claim 3 , further comprising affixing the accelerometer to an external skin surface of the subject.

5. The method of claim 1 , further comprising calculating a difference between the maximum amplitude of the second mechanomyography signal and the maximum amplitude of the first mechanomyography signal.

6. The method of claim 1 , further comprising: transmitting the first electrical stimulus from a stimulator to tissue of the subject within the intracorporeal treatment region; and

transmitting the second electrical stimulus from the stimulator to the tissue within the intracorporeal treatment region.

7. A method of identifying a change in nerve function for a nerve that extends within an intracorporeal treatment region of a subject and innervates a muscle of the subject, the method comprising:

providing a first electrical stimulus via a stimulator at a first time;

monitoring a first mechanical response of the muscle to the first electrical stimulus;

recording a maximum amplitude of the first mechanical response of the muscle to the first electrical stimulus;

providing a second electrical stimulus via the stimulator at a second time;

monitoring a second mechanical response of the muscle to the second electrical stimulus;

recording a maximum amplitude of the second mechanical response of the muscle to the second electrical stimulus;

identifying a change in nerve function if the maximum amplitude of the second mechanical response is different than the maximum amplitude of the first mechanical response; and

wherein the change in nerve function is attributable to a surgical procedure.

8. The method of claim 7 , further comprising calculating a difference between the maximum amplitude of the second mechanical response and the maximum amplitude of the first mechanical response.

9. The method of claim 7 , wherein monitoring the first mechanical response of the muscle and monitoring the second mechanical response of the muscle each respectively include:

generating a mechanomyography output signal from a non-invasive mechanical sensor configured to be disposed in mechanical communication with the muscle of the subject; and

wherein the mechanomyography output signal corresponds to a mechanical movement of the muscle.

10. The method of claim 7 , wherein the first electrical stimulus and the second electrical stimulus are each respectively provided at a common current.

11. The method of claim 7 , wherein the stimulator is an invasive medical instrument configured to extend within the intracorporeal treatment region;

wherein providing the first electrical stimulus via the stimulator includes transmitting a first electrical current from the stimulator to tissue of the subject within the intracorporeal treatment region; and

wherein providing the second electrical stimulus via the stimulator includes transmitting a second electrical current from the stimulator to the tissue within the intracorporeal treatment region.

12. A neural monitoring system for determining a change in the function of a nerve of a subject over a period of time, the system comprising:

a stimulator configured to extend within an intracorporeal treatment region of the subject and to provide an electrical stimulus therein;

a non-invasive mechanical sensor configured to be placed in communication with a muscle of the subject and to generate a mechanomyography output signal corresponding to a response of the muscle to the electrical stimulus;

a processor in communication with the stimulator and with the sensor, the processor configured to:

provide a first electrical stimulus via the stimulator at a first time;

determine a first amplitude of the mechanomyography output signal that corresponds to a response of the muscle to the first electrical stimulus;

provide a second electrical stimulus via the stimulator at a second time;

determine a second amplitude of the mechanomyography output signal that corresponds to a response of the muscle to the second electrical stimulus;

indicate a change in the function of the nerve to a user, the indication corresponding to the difference between the first amplitude and the second amplitude;

wherein the change in nerve function is attributable to a surgical procedure.

13. The system of claim 12 , wherein the first electrical stimulus and the second electrical stimulus are each respectively provided at a common current.

14. The system of claim 12 , wherein the stimulator is an invasive medical instrument.

15. The system of claim 12 , wherein each of the first and second electrical stimuli include a respective current pulse.

16. The system of claim 12 , wherein the non-invasive mechanical sensor includes an accelerometer.