Transcutaneous Auricular Vagus Nerve Stimulation for Chronic Tic Disorders/Tourette's Syndrome in Children and Adolescents

Participants will receive transcutaneous auricular vagus nerve stimulation five times per week for eight consecutive weeks.

Participants in the transcutaneous auricular vagus nerve stimulation group will receive stimulation at auricular acupoints located within the distribution area of the vagus nerve. A Hwato SDZ-II B electroacupuncture apparatus will be employed, with the two connecting clips of the same output lead attached to the acupoints on the same side. Disperse-dense wave stimulation will be applied, with the intensity adjusted according to the patient's tolerance, and each session will last 30 minutes.

Participants will receive sham stimulation five times per week for eight consecutive weeks.

Participants in the sham group will receive electrical stimulation at auricular acupoints located outside the distribution area of the vagus nerve, with a current intensity of 0.1 mA. All other procedures will be identical to those of the treatment group.

The Yale Global Tic Severity Scale (YGTSS) is a clinician-rated instrument designed to evaluate the severity of motor tics, phonic tics, and overall impairment over the preceding week. Motor and vocal tics are rated independently across five dimensions (number, frequency, intensity, complexity, and interference; range 0-5 each), and the dimension scores are summed to yield separate Motor and Vocal Tic scores (range 0-25 each) as well as a combined YGTSS Total Tic Score (range 0-50), with higher scores indicating greater tic severity. The YGTSS Impairment Rating captures tic-related distress and functional impact (range 0-50). The YGTSS Total Tic Score and the YGTSS Impairment Rating are summed to produce a YGTSS total score (range 0-100), with higher scores indicating greater overall severity.

The Yale Global Tic Severity Scale (YGTSS) is a clinician-rated instrument assessing motor tics, vocal tics, and impairment over the preceding week. Motor and vocal tics are each rated on five dimensions (number, frequency, intensity, complexity, and interference; 0-5 each), yielding Motor and Vocal Tic scores (0-25 each) and a YGTSS Total Tic Score (0-50). The YGTSS Impairment (0-50) is added to the YGTSS Total Tic Score to produce a YGTSS Total Score (0-100), with higher scores indicating greater severity.

The Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) will be used to assess the severity of obsessive-compulsive symptoms in children and adolescents. The total score of CY-BOCS ranges from 0 to 40, with higher scores indicate greater symptom severity.

The Swanson, Nolan, and Pelham Rating Scale version IV (SNAP-IV-18) will be used to assess symptoms of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. The total score of SNAP-IV-18 ranges from 0 to 54, with higher scores indicate more severe symptoms.

The Child and Adolescent Gilles de la Tourette Syndrome-Quality of Life (C&A-GTS-QOL) questionnaire will be used to assess health-related quality of life in children and adolescents with Tourette syndrome. The total score of C&A-GTS-QOL is typically transformed to a 0-100 scale, with higher scores indicating greater impairment and poorer quality of life.

An adverse event is any unexpected symptom, sign, or health condition occurring after initiation of study treatment, which may or may not be related to the study intervention. Pre-existing health conditions or diseases will only be considered as adverse events if they worsen after enrollment.