Comparison of Manual Therapy and Auricular Vagus Nerve Stimulation in Chronic Low Back Pain

Muscle Endurance Assessment

Trunk Extensor Muscle Endurance To assess the endurance of the back extensor muscles, participants will lie prone on a table with their lower extremities stabilized. The trunk will hang off the table at the level of the anterior-superior iliac spine. At the start of the test, hands will be placed on a chair. Upon beginning, participants will position their arms alongside their trunk, holding their body parallel to the floor. The duration for which this position is maintained without breaking posture will be recorded in seconds. Trunk Flexor Muscle Endurance Participants will begin in a supine position with knees flexed and arms crossed over the chest. Starting from a 60-degree trunk flexion position, they will be asked to hold this posture. The legs will be stabilized at the knees, and the time the position is maintained will be recorded in seconds.

Time frame: 6 weeks

Autonomic Nervous System Assessment

Heart rate variability will be measured using the Polar H7 heart rate sensor with a chest strap and wrist monitor (Polar H7, Polar Electro Oy). The chest strap will be placed over the sternum, and heart rate data will be recorded before and after auricular VNS. This method is validated against electrocardiogram measurements.

Time frame: 6 weeks

Flamingo Balance Test

The Flamingo Balance Test, part of the Eurofit test battery, uses a stopwatch and a 50 cm-long, 4 cm-high, and 3 cm-wide wooden beam. Participants stand on their non-dominant leg on the beam, holding the opposite leg's knee in maximal flexion with the corresponding hand while focusing on a fixed point at eye level. The timer starts once the participant releases the examiner's hand and stops when balance is lost or the body touches the ground. The test is repeated three times, and the average score is recorded.

Time frame: 6 weeks

Modified Star Excursion Balance

Y-shape, with the anterior direction at 0° and the posteromedial and posterolateral directions set at 135° and 90° angles, respectively. Participants will stand on their dominant leg, maintaining balance while reaching with the non-dominant leg as far as possible in each direction. They will then return to the starting position. Four practice trials will be provided, followed by three test trials in each direction. The average of the test trials will be recorded.