This randomized, participant- and assessor-blinded, sham-controlled study will evaluate the effectiveness of transcutaneous auricular vagus nerve stimulation (taVNS) added to standard rehabilitation in adults with complex regional pain syndrome type I (CRPS-I) affecting the hand or upper extremity.
A total of 20 participants will be randomly assigned to two parallel groups. Both groups will receive the same standard rehabilitation program 5 days per week for 4 weeks. In addition, the experimental group will receive active taVNS, while the control group will receive sham taVNS for 30 minutes per session over the same 4-week period.
The primary outcome is change in pain intensity measured using the Numerical Rating Scale. Secondary outcomes include CRPS clinical severity, hand and wrist circumference, hand function and activities of daily living, health-related quality of life, anxiety and depression symptoms, and perceived stress. Assessments will be performed at baseline, at the end of treatment at week 4, and during follow-up at weeks 8 and 12.
Diagnosis of complex regional pain syndrome type I according to the Budapest diagnostic criteria
Age 18 to 65 years
CRPS type I affecting the hand following a traumatic cause, including surgery, fracture, and/or immobilization of the hand or upper extremity
Willingness to participate in the study and provision of written informed consent
Diagnosis of complex regional pain syndrome type II
CRPS type I developing after stroke
Acute or post-acute rehabilitation following hand tendon repair
Presence of a comorbid condition that may substantially affect functional status or health-related quality of life, including decompensated heart failure, chronic kidney failure, or malignancy