Table 2.

TENS application characteristics.

Study	Device	Frequency	Pulse Width	Time	Location of the Electrodes	Types of Electrodes
[7]	Dualpex 961	10 Hz	200 μs	20 min	Trapezius muscle region (descending fibers) and submandibular region, bilaterally	2 pairs (3.0 cm × 4.0 cm)
[1]	Ibramed Neurodyn III Amethyst Line	15 Hz	250 μs	30 min	On clean skin, positioned on the upper border, at the level of the hyoid bone, and on the lower border, below the cricoid cartilage, one centimeter apart from one another	1 pair (3 cm × 5 cm)
[17]	Quark Dualpex 961	10 Hz	200 μs	20 min	Trapezius muscle and submandibular area	2 pairs (3 cm × 5 cm)
[4]	Dualpex 961	10 Hz	200 μs	20 min	Trapezius region—upper fibers, bilaterally, and in the submandibular region	2 pairs (5.0 cm × 5.0 cm)
[2]	NEURODYN II	10 Hz	200 μs	20 min	Lateral center of the larynx (thyroid cartilage) in the infrahyoid muscles, with 1 cm between them and on trapezius muscles	Rectangular and composed of silicon (30 × 50 mm)
[18]	Dualpex 961	10 Hz	200 μs	20 min	Trapezius muscle (on the descending fiber) and on both sides of the submandibular region	2 pairs (5.0 cm × 4.0 cm)
[8]	ELPHA II 3000	100 Hz	50 μs	20 min	Lateral center of the thyroid cartilage in the infrahyoid muscles and the motor point of the trapezius muscle on the descending fiber	2 pairs (5 cm × 5 cm)