Tension-type headache is a widespread disorder, with a lifetime prevalence in the general population ranging between 30% and 78%. Tension-type headache also places a financial burden on society and individuals. Myofascial pain can reduce the range of motion and patterns of muscle activation and play an important role in tension-type headache. Based on the previous studies, dry needling can reduce local and referred pain, increase range of motion and improve patterns of muscle activation in patients with myofascial pain syndrome. The effectiveness of dry needling in patients with tension-type headache is not fully known.

Objective: The aim of this study will be to investigate the effectiveness of dry needling on pain, active range of motion, functional disability, and frequency of headache in patients with episodic tension-type headache.

Method: This study will be a double-blind randomized controlled trial. Thirty-six patients with episodic tension-type headache will be randomly divided into two groups: the experimental group (dry needling and routine physical therapy) and the control group (sham dry needling and routine physical therapy). The primary outcomes will be pain intensity and active range of motion of the craniocervical region. Functional disability and frequency of headache will be considered secondary outcomes. Outcomes will be assessed before and one week after the intervention.

Study design: The experimental design will be a randomized, sham-controlled, double-blind, parallel assignment design to investigate the effectiveness of dry needling on pain, active range of motion, functional disability, and frequency of headache in patients with episodic tension-type headache. This investigation will be conducted in the physiotherapy clinic located at the School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. The ethical committee at the Iran University of Medical Sciences has approved this study (Ethical Approval Number: IR.IUMS.REC.1400.30).

Participants: The sample size of this investigation was calculated using Stata statistical software (version 14) with an α value of 0.05 to achieve a statistical power of 0.95 and an effect size of 0.2. The results revealed that a minimum of 36 patients with episodic tension-type headache is required. All of the participants will be identified and recruited by posters and word-of-mouth from the University and the surrounding local communities. Eligible participants will be explained the purpose and the examination involved in this investigation, and all eligible participants will sign a written informed consent before entering the study.

Randomization: All eligible episodic tension-type headache patients will be randomized to an experimental group (dry needling of suboccipital, levator scapula, upper trapezius, masseter, sternocleidomastoid, splenius capitis and cervicis, frontalis and temporalis muscle and routine physical therapy) and a control group (sham dry needling of suboccipital, levator scapula, upper trapezius, masseter, sternocleidomastoid, splenius capitis and cervicis, frontalis and temporalis muscle and routine physical therapy) with a ratio of 1:1. Random allocation will be executed by a researcher not involved in the assessments or interventions. Patients will be asked not to provide their grouping information to the assessor to prevent data contamination.

Procedure: Before the examination, the demographic characteristics form, including name, age, occupation, weight, height, smoking, type and duration of pain, and history of other diseases will be recorded. Primary outcomes are pain level and active range of motion of the craniocervical vertebra.

Functional disability, frequency of headache, and side effects of dry needling are considered secondary outcomes. The numeric pain rating scale, manual goniometer, and neck disability index will be used to measure pain level, active range of motion ,and functional disability, respectively. Outcomes will be examined at baseline and one week after the end of the intervention. Patients will be asked about the side effects of dry needling, such as soreness during and after dry needling, bleeding, etc., at the end of the treatment sessions. The examiner will be blinded to the intervention procedure. Patients will also be blinded to which group they belong to.

Intervention: The intervention will be for six sessions, two weeks, three times a week.

Experimental group: The method of performing the dry needling technique will be based on the methods presented by Dommerholt and Fernandez-de-Las- Penas. In this method, patients will be placed in a supine position for masseter, temporalis, sternocleidomastoid, and frontalis.

Sternocleidomastoid: The Sternocleidomastoid Both heads, clavicular and sternal, will be needled by pincer palpation after identifying the carotid artery. The needle is then inserted perpendicular to the skin and directed towards the practitioner's finger.

Temporalis: The tempolaris muscle will be needled with flat palpation. The needle is fixed with the index and middle fingers of the non-needling hand and then inserted perpendicular to the skin toward the temporalis fossa.

Masseter: The muscle will be needled with flat palpation, although pincer palpation may also be feasible. The needle will be inserted perpendicular to the skin toward the muscle belly.

Frontalis: The frontalis muscle will be needled with flat palpation. The needle will be inserted in oblique and inferior direction, 1 cun above the middle of the eyebrow, directly above the pupil when the eyes are looking straight ahead.

Patients will be placed in the lateral decubitus position for levator scapula, splenius capitis, and cervicis.

Levator scapula: The muscle will be needled via pincer palpation. For the superior (cervical) portion, the muscle is felt as a ropy muscle band of about 5mm diameter in lateral extent, between the anterior (ventral) border of the upper trapezius and the transverse process of C1. The needle will be inserted perpendicular to the skin and directed towards the practitioner's finger. For the lower (shoulder) portion, the muscle is identified over the superior medial border of the scapula. The needle will be inserted through the skin at a shallow angle, directed toward the upper, medial border of the scapula.

Splenius capitis: In splenius capitis, one finger is placed on the taut band. The needle is inserted through the skin at a shallow angle in a caudal-medial direction and directed toward the practitioner's finger.

Splenius cervicis: This muscle will be needled via pincer palpation. The needle will be inserted perpendicular to the skin from a posterior to anterior direction, directed towards the practitioner's finger or at a shallow angle. The needle may be directed medially because the muscle is laterally away from the cervical spine foramina. The needle may be through the upper fibers of the trapezius muscle.

Patients will be placed in a prone position for upper trapezius and suboccipital. Upper trapezius: The muscle will be needled via pincer palpation. The needle will be inserted perpendicular to the skin from a posterior to anterior direction directed towards the practitioner's finger or at a shallow angle. The muscle will be needled with pincer palpation. The needle will be inserted perpendicular to the skin and directed towards the practitioner's finger. The needle is kept between the fingers on the shoulder.

Suboccipital: The muscle will be needled at a point mid-way between the transverse process of C1 and the spinous process of C2. The needle will be inserted perpendicular to the skin directly in the medial half of the muscle toward the patient's opposite eye in a slightly cranial-medial direction.

One length of sterile, disposable 30 mm x 30 mm solid filament needle (Tony, China) will be used. The needles will be inserted to obtain local twitch response,which continues until no more local twitch response occurs in each session. Then the needles will be left in the place for 20 minutes. In each session, the muscles from one side will be needled.

Control group: The sham dry needling method includes inserting the needles subcutaneously and no local twitch response will be obtained. The needles will be left in the place for 20 minutes.

Routine physical therapy will be based on the guideline by Côté et al. (2019) and include information on nature, management, course of episodic tension-type headaches, and Multimodal care that includes craniocervical exercises and postural correction. To give information to patients, we will use the Persian version of tutorials provided by ICHD-3. Multimodel care consists of three exercises: chin tuck, upper trapezius and levator scapula stretch, and pectoralis major stretch. Stretching exercise will be done three times a day, with three repetitions and 30 seconds of hold position. Chin tuck will be done five times a day with ten repetitions.

Outcome measure: Outcomes will be assessed at baseline and one week after the intervention (after six sessions of treatment). The examiner will be blinded to the intervention procedure.

Pain level: The 0-100 Numeric Pain Rating Scale (NPRS) will be used to evaluate changes in the level of pain from the baseline to one week after the intervention. Zero indicates no pain and 100 indicates maximum pain that the patient experiences.

Active Craniocervical range of motion:

Active craniocervical range of motion of participants with episodic tension-type headache will be measured using a SAEHAN plastic universal two-arm goniometer with 360° goniometer face and 30-cm (11.81- in) movable arms. For measuring active flexion, extension, lateral flexion, and rotation, the participants will be asked to sit upright on a chair with a padded backrest supporting the thoracic spine with their feet flat on the floor and arms positioned comfortably on the armrests beside them. To minimize the contribution of the thoracic spine, the participants will be securely strapped across the shoulders to the chair using an inelastic belt. To standardize head posture, a visual target (white A5 paper with a black circle drawn upon it) will be adjusted to eye level in front of the participants. To measure active craniocervical flexion and extension ROM, the center of the universal goniometer will be placed over the external auditory meatus. Then, the proximal arm (fixed arm) will be positioned perpendicular to the floor and the distal arm (moving arm) will be placed over an imaginary line between the base of the nostril and the external auditory meatus. One surface of the universal goniometer face will be covered with a white sheet of paper so that the figures cannot be seen from the examiner's side. Active lateral flexion ROM will be measured by placing the center of the universal goniometer over the spinous process of C7, the proximal arm will be perpendicular to the floor, and the distal arm will be aligned with the occipital protuberance. Finally, to measure active craniocervical left and right rotation ROM, the center of the universal goniometer will be positioned at the center of the head, the proximal arm will be placed over the sagittal suture, and at the end of the movement, the distal arm Will be aligned with the nose. All the measured angles will be documented by a third person. The movements will be measured in the following sequences: flexion, extension, left lateral flexion, right lateral flexion, left rotation, and right rotation.

Functional disability: The Persian version of the neck disability index will be used to evaluate changes in functional disability from the baseline to one week after the intervention. This questionnaire includes ten activities of daily living and a total score of 50.

Frequency of headache: The participants will be given a notebook to write down the number of the days of the month involved in episodic tension-type headache.

Inclusion Criteria:

1. Diagnosis of CTTH based on the International Classification of Headache Disorders, 3rd edition
2. At least one active trigger point in each of the muscles of the sub occipital, sternocleidomastoid, upper trapezius, temporalis, levator scapula, masseter, frontalis, and splenius cervicis and capitis
3. Moderate pain intensity from 30 to 60 based on the numeric pain rating scale

Exclusion Criteria:

1. Needle phobia
2. History of surgery on head, neck, and shoulder
3. pregnancy
4. cancer, infectious diseases, or systemic diseases
5. History of involvement with other types of primary headaches
6. History of neck radiculopathy and other orthopedic neck injuries (including fractures, facet joint syndrome, etc.) in the past year.

The data sets of this study will be available upon a reasonable request to the corresponding author.