Effect of Transcutaneous Auricular Trigeminal Nerve Stimulation on Migraine

The participants with migraine headache will be randomly assigned to the two groups (TaTNS and sham TaTNS) in equal numbers using software (https://www.randomizer.org/).

The TaTNS will be applied to the intervention and control (sham) groups by a physiotherapist (AP). The intervention will be applied three days a week for 12 weeks, with 20 minutes session duration.

A dual-channel Vagustim device (Copyright Vagustim, 2023, Vagustim Health Technologies, San Francisco, CA) will be used for stimulation. In both groups, clip-on bipolar electrodes were placed on the upper-anterior part of the auricle. The bilateral auricular stimulation protocols as follows: Biphasic rectangular current duration 20 minutes, current amplitude 250 microseconds, frequency 60 Hertz, current intensity increased to a maximum of 16 mA.

Sham TaTNS The sham-TaTNS application was performed to mimic active TaTNS. The electrodes were placed in the same anatomical location as in the active TaTNS application, but stimulation was applied at a very low intensity (below the sensory threshold, 1 mA) that would not produce a neuromodulatory effect, or only a brief stimulation was applied at the beginning to create a temporary sensation on the skin. This method provides an experience similar to the active application in terms of participants' perception of stimulation, but does not create effective physiological stimulation in the trigeminal nerve.

The sham group received a frequency of 1 Hz and a current intensity of up to 1 mA.

To assess the success rate of the blinding technique, at the end of the treatment period, each participant was asked to guess which treatment group they belonged to. Additionally, level of confidence in their guesses regarding the groups they belonged to was assessed using the Visual Analog Scale (VAS) (0-10 cm).

Inclusion criteria

• being aged 18-45 years,
• being literate in Turkish
• having been diagnosed with episodic migraine with aura and migraine without aura by a neurologist according to the International Classification of Headache Disorders,
• having a history of migraine for at least 6 months with at least 2 attacks per month in the last 3 months.

Exclusion criteria

• being pregnant or breastfeeding;
• regular use of analgesics or non-steroidal anti-inflammatory drugs for more than 15 days per month;
• pacemaker implantation;
• a history of addiction, syncope or abnormal ECG findings;
• a history of intracranial haemorrhage or significant head trauma;
• a diagnosis of epilepsy, severe anxiety or depression;
• other types of headaches, including paresthesia or medication-overuse headaches;
• cognitive, visual, or auditory problems that would prevent participation in the study.