Non-invasive nerve stimulation to treat or prevent autism spectrum disorders and other disorders of psychological development
Devices, systems and methods are disclosed for treating or preventing an autism spectrum disorder, a pervasive developmental disorder, or a disorder of psychological development. The methods comprise transmitting impulses of energy non-invasively to selected nerve fibers, particularly those in a vagus nerve. The nerve stimulation may be used as a behavior conditioning tool, by producing euphoria in an autistic individual. Vagus nerve stimulation is also used to modulate circulating serotonin levels in a pregnant woman so as to reduce the risk of having an autistic child; modulate the levels of growth factors within a child; promote balance of neuronal excitation/inhibition; modulate the activity of abnormal resting state neuronal networks; increase respiratory sinus arrhythmia; and avert episodes of motor stereotypies with the aid of forecasting methods.
1. A device for treating or preventing a behavioral disorder in a patient, comprising:
a housing having a contact surface for contacting an outer skin surface of the of a neck of a patient;
a power source within the housing; and
wherein the power source generates and transmits an electric current through the contact surface and the outer skin surface of the neck to a vagus nerve within the patient non-invasively to generate an electrical impulse at the vagus nerve, wherein the electrical impulse is sufficient to modify the behavioral disorder in the patient, wherein the electrical impulse comprises bursts of about 2 to about 20 pulses with a silent intra-burst interval between each burst and wherein each burst has a frequency of about 1 to about 100 bursts per second.
2. The device of claim 1 further comprising an electrode within the housing coupled to the contact surface.
3. The device of claim 2 further comprising a conductor within the housing coupled to the electrode and the power source, wherein the power source generates and transmits the electric current through the conductor, electrode and the contact surface to the vagus nerve.
4. The device of claim 2 wherein the power source comprises a signal generator coupled to the electrode within the housing.
5. The device of claim 3 wherein the conductor is a first conductor, the device further comprising a second conductor coupling the electrode to the contact surface.
6. The device of claim 5 wherein the second conductor comprises an electrically conductive fluid within the housing between the electrode and the contact surface.
7. The device of claim 6 wherein the electrically conductive fluid comprises an electrically conductive gel.
8. The device of claim 1 wherein each pulse is about 50 to 1000 microseconds in duration.
9. The device of claim 1 the electrical current generates an electric field at the vagus nerve above a threshold for generating action potentials within A and B fibers of the vagus nerve and below a threshold for generating action potentials within C fibers of the vagus nerve.
10. The device of claim 1 wherein the electrical current generates an electric field at the vagus nerve above a threshold for generating action potentials within fibers of the vagus nerve responsible for activating neural pathways causing release of inhibitory neurotransmitters within a brain of the patient.
11. The device of claim 10 wherein the inhibitory neurotransmitters comprise GABA, norepinephrine, or serotonin.
12. The device of claim 1 wherein the behavioral disorder comprises attention-deficit hyperactivity disorder (ADHD).
13. The device of claim 1 wherein the behavioral disorder comprises an autism spectrum disorder.
14. The device of claim 1 wherein the behavioral disorder comprises Asperger syndrome.