Effect of Transcutaneous Vagus Nerve Stimulation on Upper Limb Function in Stroke Patients

Patients in this group will be treated with 12 sessions of transcutaneous auricular nerve stimulation, three sessions per week for four weeks. The stimulation of the left auricular branch of the vagus nerve will be performed by conventional transcutaneous electrical nerve stimulation (TENS) through a Gamna Duo 200 electrotherapy device with one channel and two electrodes (5mm diameter disposable adhesive stimulation electrodes). The TENS parameters will be used: 30 30-minute treatment time, a pulse width of 200 milliseconds, and a pulse frequency of 20 hertz. The intensity of stimulation will be individually adjusted according to the patient's perceptual threshold. The perceptual threshold (PT) is defined as the minimum amount of electricity required to perceive electrical stimulation on the skin described as a pricking or tingling sensation. The stimulation intensity will be set at super-threshold levels, such as 200% of the patient's perceptual threshold.

The selected physical therapy program session will be from 25 to 30 minutes, three sessions per week for four weeks. The program will be selected mainly for stretching for shortened upper limb muscles, strengthening for weak upper limb muscles, occupational therapy for hand, trunk, and pelvic control exercises, and gait training.