Effect of Non-Invasive Neuromodulation on Primary Chronic Pain, Including Post-COVID-19

30 minutes of electrical stimulation on the afferent portion of the vagal nerve on the cymba conchae of the ear, in the following configuration: 30 seg ramp up, 30 seg on, 30 seg off in intensity on which the volunteer feels a light tingling.

Magnetic stimulation on the efferent portion of the vagal nerve on the neck, on the following configuration: 20Hz, 25 pulses in the trein, in every inhalation, for 20 inhalations with 50% of machine capacity (500 pulses total).

rTMS intermitent theta- burst on the left DLPFC, on the following configuration: 50 Hz in treins of 5Hz, with 110% of the resting motor limiar and 600 pulses in 3 minutes.

Simulated taVNS (SHAM) on helix left ear, that is the same as taVNS, but during only 1 minute