The study used a repeated measures design. After instructions on the use of a standard nVNS device, the patient was given an "at-home" nVNS-treatment protocol for 24-month run-in period, that was divided in three 8-month treatment blocks where each block-period consisted of active nVNS with specific settings and daily stimulation time. Each block was divided in 4-time assessment i.e., AAAA-BBBB-CCCC, once every 2 months. No washout period was included.
