Method for determining stimulation parameters

1. A method of determining an optimal therapeutic stimulus (pulsewidth, amplitude), for stimulating nerve with at least one electrode ( 17 ), the method comprising:

(a) providing a predetermined calibration curve defined by sets of paired parameter values (pulsewidth, amplitude);

(b) determining an optimal pulsewidth value, P 1 , by presenting sets of paired parameter values (pulsewidth, amplitude) that are part of the calibration curve, until a threshold stimulus parameter pair (P 1 , A 1 ) is found which elicits a threshold or a just noticeable response in a patient; and

(c) determining an maximum comfortable amplitude value, A 2 , by holding constant the pulsewidth, P 1 , found in the preceding step.

2. The method of claim 1 , wherein the threshold stimulus (P 1 , A 1 ) is measured by a sensing instrument.

3. The method of claim 2 , wherein the sensing instrument is selected from the group consisting of a plethysmograph, an accelerometer and a transducer for detecting evoked potentials.

4. The method of claim 1 , further comprising:

(d) determining the therapeutic value, A 3 , by holding pulsewidth, P 1 , found in step (b) constant, and setting A 3 equal to A 2 ,

wherein step (c) is accomplished by incrementally increasing stimulus amplitude until the maximum comfortable threshold amplitude, A 2 , is found, while holding the pulsewidth, P 1 , found in step (b) constant.

5. The method of claim 1 , further comprising:

(d) determining the therapeutic value, A 3 , by holding pulsewidth, P 1 , found in step (b) constant, and setting A 3 value less than A 2 ,

wherein step (c) is accomplished by incrementally increasing stimulus amplitude until the maximum comfortable threshold amplitude, A 2 , is found, while holding the pulsewidth, P 1 , found in step (b) constant.

6. The method of claim 1 , wherein the calibration curve has an elbow occurring at a pulsewidth value of between about 100 to 300 microseconds.

7. The method of claim 1 , wherein step (c) for determining A 2 is accomplished by multiplying the amplitude A 1 found in step (b) by a multiplicative factor.

8. The method of claim 7 , wherein the multiplicative factor is about 1.4.

9. The method of claim 1 , wherein the calibration curve is derived based on pre-measurement of maximum electrode impedance setting and ensuring that maximum comfortable threshold voltage is well below system compliance voltage.

10. The method of claim 1 , wherein the calibration curve is derived based on minimizing current drain, in accordance with the relation:

P drain ={( I stim *Pulsewidth stim *Rate stim ) 2 *Z combination }+P sys .

11. The method of claim 1 , wherein the calibration curve provides a UR that is sufficiently wide to provide stimulation to yield both a perception threshold and a maximum comfortable threshold.

12. The method of claim 1 , wherein the step (b) of determining (P 1 , A 1 ) is performed using a software program to present the various parameter values (pulsewidth, amplitude) in accordance with the predetermined calibration curve.

13. The method of claim 1 , wherein the at least one electrode ( 17 ) chosen presents the highest impedance among possible available electrodes.

14. A method of determining optimal stimulus pulsewidth and amplitude for stimulating nerves with at least one electrode ( 17 ), the method comprising:

(a) providing a predetermined calibration curve comprising a set of pulsewidth ( 70 ) and amplitude values; and

(b) selecting a stimulus pulsewidth ( 70 ) and an amplitude which provides a maximum comfortable threshold by delivering stimuli to the at least one electrode ( 17 ), the stimuli chosen from pulsewidth and amplitude parameter pairs which are part of the calibration curve.

15. The method of claim 14 , wherein the calibration curve is derived based on pre-measurement of maximum electrode impedance setting and ensuring that the maximum threshold is well below the system compliance voltage.

16. The method of claim 14 , wherein the calibration curve is derived based on minimizing current drain, in accordance with the relation:

P drain ={( I stim *Pulsewidth stim *Rate stim ) 2 *Z combination }+P sys .

17. The method of claim 14 , wherein the calibration curve provides a UR that is sufficiently wide to provide stimulation to yield both a perception threshold and a maximum threshold.

18. The method of claim 14 , wherein the at least one electrode ( 17 ) chosen presents the highest impedance among possible available electrodes.

19. The method of claim 14 , wherein in step (b) delivering stimuli to the at least one electrode ( 17 ), stimuli chosen from pulsewidth and amplitude parameter pairs which are part of the calibration curve is performed by using a software program.