This study is a randomized, double-blind, sham-controlled feasibility trial designed to assess the acceptability and preliminary efficacy of Transcutaneous Auricular Neurostimulation (tAN) for individuals with Temporomandibular Disorders (TMD). Approximately 40 participants will be enrolled to evaluate whether daily, home-based tAN sessions-which deliver mild electrical pulses to the auricular branch of the vagus nerve-can effectively reduce chronic orofacial pain and improve associated cognitive and psychosocial dysfunctions. The study monitors feasibility through retention and adherence rates while tracking secondary outcomes such as pain intensity, cognitive flexibility, and mood changes using validated scales and wearable smartwatch data . Ultimately, this research aims to generate the critical data necessary to inform larger clinical trials and potentially offer a non-pharmacological, non-invasive treatment option for patients refractory to traditional TMD therapies.

Inclusion Criteria:

• Age 18 to 65 years.
• Diagnosis of temporomandibular disorder (TMD) based on the Diagnostic Criteria for Temporomandibular Disorders (DC-TMD).
• Pain intensity of at least 4/10 on the Numeric Rating Scale (NRS) over the past two weeks.
• Chronic pain duration of at least three months, consistent with diagnosis of chronic TMD.
• Willingness to self-administer transcutaneous auricular nerve stimulation (tAN) at home and comply with study procedures.
• Fluency in English to ensure comprehension of study materials and assessments.
• Access to a smartphone or computer with internet to complete electronic study surveys and check-ins with the research team.

Exclusion Criteria:

• Neurological conditions that may interfere with study outcomes, including epilepsy, stroke, multiple sclerosis, or traumatic brain injury.
• Use of implanted neuromodulation devices, such as vagus nerve stimulators, deep brain stimulators, or cochlear implants.
• Unstable or severe psychiatric disorders, including active psychosis or severe depression with suicidal ideation.
• Pregnancy or intention to become pregnant during the study period.
• Skin conditions or other contraindications that prevent safe electrode placement on the auricular region (e.g., metal in the cymba concha that is unable or not willing to remove).
• History of trauma (e.g., skull fracture) or periauricular surgery (e.g., temporomandibular joint replacement, acoustic neuroma removal) which would affect the location and function of the target peripheral innervation.
• Use of both surgical and non-surgical bone conduction hearing devices.