Devices and methods for monitoring non-invasive vagus nerve stimulation
Devices and methods are disclosed that treat a medical condition, such as migraine headache, by electrically stimulating a nerve noninvasively, which may be a vagus nerve situated within a patient's neck. Preferred embodiments allow a patient to self-treat his or her condition. Disclosed methods assure that the device is being positioned correctly on the neck and that the amplitude and other parameters of the stimulation actually stimulate the vagus nerve with a therapeutic waveform. Those methods comprise measuring properties of the patient's larynx, pupil diameters, blood flow within an eye, electrodermal activity and/or heart rate variability.
1. A method for treating a medical condition of a patient, the method comprising:
contacting an outer skin surface of the patient with a contact surface of a housing;
generating an electrical impulse within the housing;
transmitting, as the contact surface contacts the outer skin surface, the electrical impulse from the housing, non-invasively, through the outer skin surface, to a nerve at a target region within the patient such that the electrical impulse modulates the nerve;
measuring a physiological response of the patient, wherein the physiological response is directly associated with modulation of the nerve based on the transmitting; and
detecting, based on the physiological response, whether the electrical impulse was transmitted to the nerve.
2. The method of claim 1 , wherein the measuring is carried out by measuring a property of a voice of the patient, wherein the nerve is a vagus nerve.
3. The method of claim 1 , wherein the measuring is carried out by measuring a laryngeal electromyographic signal of the patient.
4. The method of claim 1 , wherein the measuring is carried out by measuring an electroglottographic signal of the patient.
5. The method of claim 1 , wherein the measuring is carried out by measuring at least one of a pupil diameter or a blood flow within an eye of the patient.
6. The method of claim 1 , wherein the measuring is carried out by measuring at least one of electrodermal activity or heart rate variability.
7. The method of claim 1 , wherein the measuring is carried out by measuring a property of an autonomic nervous system of the patient.
8. The method of claim 1 , wherein the measuring is carried out by measuring a vagal artery blood flow of the patient.
9. The method of claim 1 , wherein the measuring is carried out by measuring a cerebral blood flow of the patient.
10. The method of claim 1 , wherein the measuring is carried out by measuring at least one of an evoked potential or an electroencephalogram of the patient.
11. The method of claim 1 , wherein the measuring is carried out by measuring at least one of a pain threshold, a sway, or a chemical within blood of the patient.
12. The method of claim 1 , wherein the measuring step is carried out by detecting fluorescent material that has been applied onto or under a skin of the patient.
13. The method of claim 1 , wherein the measuring step is carried out with at least one of an accelerometer or a gyroscope.
14. The method of claim 1 , wherein the electrical impulse comprises bursts of pulses with a frequency of about 1 to about 100 bursts per second.
15. The method of claim 14 , wherein the pulses have a duration of about 50 to about 1000 microseconds.
16. The method of claim 1 , wherein the contacting is carried out by contacting an outer skin surface of a neck of the patient.
17. A method of testing a nerve stimulator, the method comprising:
generating an electrical impulse within a housing;
transmitting, as the housing is in contact with an outer skin surface of a patient, the electrical impulse from the housing, non-invasively, through the outer skin surface to a nerve at a target region within the patient;
measuring a physiological response of the patient, wherein the physiological response is directly associated with the transmitting; and
detecting, based on the physiological response, whether the electrical impulse modulates the nerve, wherein the nerve is a vagus nerve.