The Effect of Transauricular Electrical Vagal Nerve Stimulation on Temporal Summation of Pain in Patients With Back Pain

Inclusion Criteria: * Patients with chronic low-back pain * age 30-60 yrs old * without heart disease * low-back pain intensity at least 4 out of 10 points measured using NRS-10 * without cognitive deficits (Mini Mental State Shake \< 23) Exclusion Criteria: * opioid medication * more than 1 low-back surgery * sensory of motor neurological deficits at the level of back pain * spinal stenosis * diabetic polyneuropathy * skin pathology at the site (cymba conchae) of stimulation