Devices and methods for treating medical disorders with evoked potentials and vagus nerve stimulation
Devices, systems and methods for treating medical disorders, such as migraine or other primary headaches, or fibromyalgia, by noninvasive electrical stimulation of a vagus nerve, used in conjunction with the measurement of evoked potentials (EPs). The system comprises a stimulator that is applied to the surface of the patient's neck to apply electrical impulses sufficient to stimulate a cervical vagus nerve, scalp electrodes that are used to measure EPs that are evoked by that stimulation, feedback or biofeedback circuits to vary the stimulation based upon EP characteristics, and other sensory stimulation modalities that produce EPs. The system is preferably used to optimize the placement of the stimulator, to test whether a patient is a suitable candidate for treatment using vagus nerve stimulation, and to select the stimulation parameters that optimized acute or chronic treatment, e.g., by correcting an EP habituation deficit.
1. A method comprising:
applying a first sensory stimulus to a patient having a medical condition;
measuring a first baseline evoked potential from the patient, wherein the first baseline evoked potential is evoked by the first sensory stimulus;
applying a treatment for a medical condition to the patient;
applying a second sensory stimulus to the patient after the treatment;
measuring an acute response of the patient to the medical condition as a function of a characteristic of the treatment, wherein the acute response comprises a second evoked potential evoked by the second sensory stimulus; and
comparing the acute response to the first baseline evoked potential to determine whether the patient is a responder to the treatment.
2. The method of claim 1 , wherein the sensory stimulus comprises at least one of a visual, auditory, somatosensory, painful, olfactory, gustatory, vestibular, or interoceptive stimulus.
3. The method of claim 1 , wherein the treatment comprises a vagus nerve stimulation.
4. The method of claim 1 , wherein the treatment comprises applying an electrical impulse transcutaneously through an outer skin surface of a neck of the patient to a vagus nerve of the patient.
5. The method of claim 4 , further comprising:
varying a plurality of different parameters of the treatment based on comparing the acute response to the first baseline evoked potential to determine whether the patient is a responder to the different parameters.
6. The method of claim 5 , wherein the different parameters comprise at least one of an amplitude or a frequency of the electrical impulse.
7. The method of claim 5 , wherein the different parameters comprise applying the electrical impulse to a different location on the neck of the patient.
8. The method of claim 5 , wherein the different parameters comprise applying the electrical impulse via a different orientation on the neck of the patient.
9. The method of claim 1 , wherein the medical condition comprises a primary headache.
10. The method of claim 1 , wherein the acute response comprises a reduction in pain of the patient.
11. The method of claim 1 , wherein the patient exhibits a reduction in magnitude of the second evoked potential compared to the first evoked potential.
12. The method of claim 1 , wherein the patient exhibits an increase in magnitude of the second evoked potential compared to the first evoked potential.
13. A method comprising:
applying a sensory stimulus to a patient having a medical condition;
measuring a first baseline evoked potential from the patient, wherein the first baseline evoked potential is evoked by the sensory stimulus;
applying a treatment for the medical condition to the patient, wherein the treatment comprises a treatment paradigm comprising an application of the electrical impulse in multiple doses per day for a period of time greater than 1 day and less than 3 months;
measuring a second baseline evoked potential from the patient as a function of a characteristic of the treatment; and
comparing the second baseline evoked potential to the first baseline evoked potential to determine whether the patient is a responder to the treatment.
14. The method of claim 13 , wherein the sensory stimulus comprises at least one of a visual, auditory, somatosensory, painful, olfactory, gustatory, vestibular, or interoceptive stimulus.
15. The method of claim 13 , wherein the medical condition comprises a primary headache.
16. The method of claim 13 , wherein the second baseline evoked potential is measured after the treatment paradigm has been completed.
17. The method of claim 16 , wherein the second baseline evoked potential comprises a reduction in pain of the patient.
18. The method of claim 16 , wherein the second baseline evoked potential comprises a reduction in a number of headache days of the patient.
19. The method of claim 13 , wherein the patient exhibits a deficit with regard to a habituation of the evoked potential.
20. The method of claim 13 , wherein the treatment increases a habituation of the second evoked potential.
21. The method of claim 13 , wherein the treatment comprises an application of an electrical impulse transcutaneously through an outer skin surface of a neck of the patient to a vagus nerve of the patient.