Apparatuses and methods for transdermal electrical stimulation of nerves to modify or induce a cognitive state
Portable transdermal electrical stimulation (TES) applicators for modifying a subject's cognitive state by applying stimulation to the subject's skin. One or more electrode may be on the subject's mastoid, and/or on or near the back of the subject's neck. The portable applicators are configured and adapted to be lightweight and may be wearable, and to deliver a high-intensity TES able to evoke or enhance a predetermined cognitive effect to stimulate either the trigeminal, facial and/or cervical plexus. These TES applicators may include a pair of electrodes and a TES control module comprising a processor, a timer and a waveform generator.
1. A method comprising:
activating a transdermal electrical stimulation (TES) applicator to deliver a pulsed, asymmetric, biphasic transdermal electrical stimulation having a frequency of 250 Hz or greater and an intensity of greater than 3 mA between an anode positioned on the subject's skin at a first location and a cathode on the subject's skin at a second location; and
applying the biphasic transdermal electrical stimulation between the anode and cathode until the subject's sympathetic nervous system is suppressed;
wherein the first location is on the back of the subject's neck at a medial portion of the neck and the second location is on the back of the subject's neck at a medial location above or below the first location.
2. The method of claim 1 , wherein modifying the subject's sympathetic nervous system by applying the biphasic transdermal electrical stimulation for 10 seconds or longer comprises applying intervals of the biphasic transdermal stimulation having a frequency of 250 Hz or greater and an intensity of greater than 3 mA during the 10 seconds or longer.
3. The method of claim 1 , wherein activating the TES applicator to deliver the pulsed, asymmetric, biphasic transdermal electrical stimulation further comprises, applying a capacitive discharge current to the anode and cathode to oppose any capacitance built-up during the delivery of the biphasic transdermal electrical stimulation.
4. The method of claim 1 , wherein activating the TES applicator to deliver the pulsed, asymmetric, biphasic transdermal electrical stimulation further comprises, applying a capacitive discharge current periodically within each cycle of the biphasic transdermal electrical stimulation to oppose any capacitance built-up during the delivery of the biphasic transdermal electrical stimulation.
5. The method of claim 1 , wherein activating the TES applicator comprises activating the TES applicator to deliver the biphasic transdermal electrical stimulation having a duty cycle of greater than 10 percent.
6. The method of claim 1 , wherein activating the TES applicator comprises wirelessly triggering activation of the TES applicator.
7. The method of claim 1 , further comprising varying the applied biphasic transdermal electrical stimulation while the biphasic transdermal stimulation is applied.
8. The method of claim 1 , further comprising varying the applied biphasic transdermal electrical stimulation while keeping the biphasic transdermal electrical stimulation within a duty cycle of greater than 10 percent, the frequency of 750 Hz or greater, and the intensity of greater than 3 mA.
9. The method of claim 1 , further comprising ramping the biphasic transdermal electrical stimulation during the application by modifying one or more of the intensity, frequency and duty cycle from an initial state and then restoring the one or more of the intensity, frequency and duty cycle back to the initial state.
10. A method of modifying a subject's sympathetic nervous system, the method comprising:
positioning an anode on a medial portion of the subject's neck and a cathode on the medial portion of the subject's neck below or above the anode, wherein the anode is smaller than the cathode;
activating a wearable transdermal electrical stimulation (TES) applicator to deliver a pulsed, asymmetric, biphasic transdermal electrical stimulation having a frequency of 250 Hz or greater and an intensity of greater than 3 mA between the anode and the cathode; and
applying the biphasic transdermal electrical stimulation between the anode and the cathode until the subject's sympathetic nervous system is suppressed.
11. A method of modifying a subject's sympathetic nervous system, the method comprising:
positioning an anode on a medial portion of the subject's neck and a cathode on the medial portion of the subject's neck below or above the anode, wherein the cathode is smaller than the anode;
activating a wearable transdermal electrical stimulation (TES) applicator to deliver a pulsed, asymmetric, biphasic transdermal electrical stimulation having a frequency of 250 Hz or greater and an intensity of greater than 3 mA between the anode and the cathode; and
applying the biphasic transdermal electrical stimulation between the anode and the cathode until the subject's sympathetic nervous system is suppressed.