Non-invasive magnetic or electrical nerve stimulation to treat or prevent dementia

Abstract

Devices, systems and methods are disclosed for treating or preventing dementia, such as Alzheimer's disease. The methods comprise transmitting impulses of energy non-invasively to selected nerve fibers, particularly those in a vagus nerve, that modulate the activity of a patient's locus ceruleus. The transmitted energy impulses, comprising magnetic and/or electrical energy, stimulate the selected nerve fibers to cause the locus ceruleus to release norepinephrine into regions of the brain that contain beta-amyloids. The norepinephrine counteracts neuroinflammation that would damage neurons in those regions and the locus ceruleus, thereby arresting or slowing the progression of the disease in the patient.

1 . A device for treating or preventing dementia in a patient comprising:
 a housing having an interior portion and an exterior portion;   an electrically permeable contact surface formed on at least part of the exterior portion of the housing and configured for contacting an outer skin surface of a neck of the patient;   one or more electrodes electrically coupled to the electrically permeable contact surface;   a power source within the interior portion of the housing and configured to generate an electric field sufficient to transmit an electric current non-invasively and transcutaneously via the one or more electrodes through the electrically permeable contact surface and the outer skin surface of the neck of the patient to a vagus nerve within the patient; and   wherein the electric current is sufficient to modify dementia in the patient.   
     
     
         2 . The device of  claim 1  wherein the energy source comprises a signal generator. 
     
     
         3 . The device of  claim 1  wherein the energy source comprises a battery. 
     
     
         4 . The device of  claim 1  further comprising a volume of electrically conductive fluid within the interior portion of the housing and at least partially surrounding the one or more electrodes. 
     
     
         5 . The device of  claim 1  wherein the electric current comprises bursts of pulses and with each of the bursts followed by a silent intra-burst period. 
     
     
         6 . The device of  claim 5  wherein the bursts have a frequency of about 1 to about 100 bursts per second. 
     
     
         7 . The device of  claim 6  wherein the frequency is about 5 to 50 Hz. 
     
     
         8 . The device of  claim 5  wherein the electric current comprises about 2 to 50 pulses per burst with each pulse having a duration of about 50 to 1000 microseconds. 
     
     
         9 . The device of  claim 8  wherein the duration of the pulses is about 200 to 400 microseconds. 
     
     
         10 . The device of  claim 1  wherein the electric current is sufficient to modulate the vagus nerve and cause the vagus nerve to generate an action potential. 
     
     
         11 . The device of  claim 1  wherein the housing is a handheld device. 
     
     
         12 . The device of  claim 1  wherein the electric 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. 
     
     
         13 . The device of  claim 1  wherein the electric current generates an electric field at the vagus nerve of about 10 to about 600 V/m. 
     
     
         14 . The device of  claim 13  wherein the electric field is less than 100 V/m. 
     
     
         15 . The device of  claim 1  wherein the electric 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. 
     
     
         16 . The device of  claim 15  wherein the inhibitory neurotransmitters comprise norepinephrine. 
     
     
         17 . A device for treating or preventing dementia in a patient comprising:
 a housing comprising an exterior portion having one or more electrodes for contacting an outer skin surface of a neck of the patient;   an energy source within the housing configured to generate an electric current and transmit the electric current transcutaneously and non-invasively through the outer skin surface of the neck of the patient to a vagus nerve within the patient; and   wherein the electric current is suffient to treat or prevent dementia in the patient.   
     
     
         18 . The device of  claim 17  wherein the energy source comprises a battery and a signal generator, wherein the one or more electrodes are coupled to the signal generator within the housing. 
     
     
         19 . The device of  claim 17  wherein the electric current comprises bursts of pulses with each of the bursts followed by a silent intra-burst period such that the bursts have a frequency of about 1 to about 100 Hz. 
     
     
         20 . The device of  claim 19  wherein the electric current comprises about 2 to 50 pulses per burst, with each pulse have a duration of about 50 to about 1000 microseconds.