Myotensive Extraocular Muscle Techniques Added to Manual Therapy for Migraine Without Aura

This continuous quantitative variable assesses the intensity of pain experienced by the patient. The VAS consists of a 10 cm horizontal line whose endpoints are anchored by the expressions "no pain" on the left end and "worst pain imaginable" on the right end. The patient is asked to mark the point along this line that best represents their subjective perception of pain at that moment, and the score is obtained by measuring in centimeters from the left end to the mark made.

This discrete quantitative variable, originally named the Craniofacial Pain and Disability Inventory (CF-PDI), is a questionnaire specifically designed to assess pain and disability in patients suffering from craniofacial pain, such as headaches, temporomandibular disorders, and related conditions.

The aim of the questionnaire is to evaluate the severity of craniofacial pain and its impact on patients' functional, emotional, and social activities.

It is structured into items grouped into four dimensions: the impact on daily activities, work, interpersonal relationships, and emotional state. Each item is rated on a 5-point Likert scale ranging from 0 to 4, where 0 indicates minimal impact and 4 indicates maximum perceived impact in each dimension. The total score can reach up to 84 points, with higher scores reflecting greater levels of disability and impact of craniofacial pain on the patient's life.

This tool has demonstrated excellent psychometric properties, with high reliability i

This continuous quantitative variable corresponds to a tool used to assess the impact of migraine on patients' quality of life. The MSQ includes 14 items that explore the frequency and intensity of migraine episodes and their impact on work activities, social relationships, emotional well-being, and overall health status. Responses are rated using a Likert-type scale.

The questionnaire is divided into subscales corresponding to different domains of life affected by migraine: physical functioning, emotional functioning, and social functioning. The total score is obtained by summing the subscale scores.

Each of the 14 items is rated on a 6-point Likert scale ranging from 1 = "all the time" to 6 = "never," thus evaluating how frequently migraine interferes with different aspects of the patient's life.

To facilitate interpretation and standardization, raw scores from the MSQ are transformed to a standardized 0-100 scale. This transformation is achieved by subtracting the minimum possible

This continuous quantitative variable is used to measure health-related quality of life, encompassing multiple aspects of physical and mental well-being. The SF-36 consists of 36 items divided into eight subscales evaluating different dimensions of health: Physical Functioning (PF), Social Functioning (SF), Role Emotional (RE), Vitality (VT), Mental Health (MH), Bodily Pain (BP), General Health (GH), and Physical Health (PH). Each subscale is scored from 0 to 100, where higher scores indicate better quality of life in that particular domain. Subscale scores can be analyzed individually or combined to generate an overall quality of life index.

The SF-36 was developed by Ware et al. (1992) and adapted and validated into Spanish as part of the international IQOLA project by Vilagut et al. The SF-36 has demonstrated excellent reliability and validity across diverse populations and clinical contexts. It shows high internal consistency, with Cronbach's alpha coefficients generally above 0.8

This continuous quantitative variable is a self-administered tool designed to evaluate the impact of migraine on patients' daily activities over the past three months. It consists of five questions assessing the number of days lost in work, household, and social activities due to migraine. The total score is obtained by summing responses to these five questions and is classified into four disability grades: 0-5 points: little or no disability 6-10 points: mild disability 11-20 points: moderate disability ≥21 points: severe disability Additionally, the questionnaire includes two supplemental questions that gather information on the frequency of migraine episodes and the average pain intensity on a 0-10 scale. The MIDAS has shown moderately high test-retest reliability and good convergent validity.

This continuous quantitative variable consists of a questionnaire with six items assessing the impact of headaches across various aspects of a patient's life, including pain, functional limitation, fatigue, cognition, and emotional status, providing a global overview of headache burden. Each item is rated on a 5-point frequency scale: never (6 points), rarely (8 points), sometimes (10 points), very often (11 points), and always (13 points).

The total score ranges from 36 to 78 and is interpreted as follows:

≤49: little or no impact 50-55: some impact 56-59: substantial impact

≥60: severe impact The HIT-6 has demonstrated excellent psychometric properties, with internal consistency (Cronbach's alpha) ranging from 0.78 to 0.90 across studies, strong validity through correlations with other migraine assessment scales such as MIDAS and SF-36, and high reproducibility, with test-retest coefficients above 0.80.

This continuous quantitative variable will be measured using a gravity goniometer, expressed in degrees. Participants will be asked to actively perform flexion and extension movements. Three measurements will be taken, and the mean value will be recorded.

The gravity goniometer has demonstrated validity and reliability for assessing cervical range of motion, with excellent intra-rater reliability (ICC > 0.85) according to Youdas et al., and good concurrent validity when compared to three-dimensional systems (differences < 5°). It also shows adequate inter-rater reliability when standardized protocols are followed.

This continuous quantitative variable will be measured in degrees using a gravity goniometer. Participants will be asked to actively perform right (RSB) and left (LSB) lateral flexion movements three times each, and the mean value will be calculated.

This continuous quantitative variable will be measured in degrees using a gravity goniometer. Participants will be asked to actively perform right (RR) and left (LR) cervical rotation three times each, and the mean value will be obtained

Assessed using the Cranio-Cervical Flexion Test (CCFT) with the Chattanooga Stabilizer™ pressure biofeedback device. The Activation Score reflects the highest pressure level (in mmHg) that the participant can achieve and maintain with correct deep cervical flexor activation and without recruitment of superficial musculature.

Assessed using the Cranio-Cervical Flexion Test (CCFT) with the Chattanooga Stabilizer™ pressure biofeedback device. The Performance Index represents the product of the pressure level achieved and the duration maintained, providing a quantitative measure of deep cervical flexor endurance and control.

This categorical quantitative variable measures the spontaneous tilt or rotation of the head axis relative to the vertical plane in relaxed standing posture, while the participant fixates on a target 50 cm away at eye level.

Measured with a gravity goniometer and categorized as:

• Category 0: symmetrical position (0°)
• Category 1: mild deviation (1°-4°)
• Category 2: moderate deviation (5°-9°)
• Category 3: severe deviation (≥10°)

This dichotomous qualitative variable records the presence or absence of pain during eye movement or fixation in each of the nine gaze positions: primary gaze, dextroversion, levoversion, supraversion, infraversion, dextroelevation, levoelevation, dextrodepression, and levodepression.

The examiner asks the participant to look at a target placed in each position for 4 seconds, noting any painful sensation. This helps detect patterns of oculomotor dysfunction and serves as an indirect clinical indicator of tension or hypertonicity in extraocular muscles

This ordinal qualitative variable assesses whether the participant can perform complete and unrestricted eye movements in all nine gaze directions.

The evaluation follows a standardized clinical observation using the "H-test" or star pattern, with a pen, pointer, or finger moved at approximately 50 cm distance.

Each gaze direction is categorized as:

• 0: full and symmetrical movement without restrictions or compensatory saccades
• 1: incomplete movement or mild hypofunction, requiring saccades to reach the target
• 2: clearly limited or absent movement

This dichotomous ordinal qualitative variable records whether there is a symptomatic improvement (pain reduction and/or increased ocular mobility) after manual correction of head posture in neutral standing.

Categorized as:

• 0: no change in symptoms or ocular motility
• 1: improvement in symptoms and/or ocular motility range

The Thorington test will be used to measure latent ocular deviation, expressed in prism diopters (∆), through optical dissociation with a Maddox rod and direct reading on a calibrated scale. This method provides high intra-examiner, inter-examiner, and test-retest reliability, and is sensitive to small changes following an intervention. Its internal validity relies on strict standardization of distance, illumination, rod orientation, and accommodative demand, while its external validity is supported by its widespread use as a reference test in binocular vision research. Due to its consistency, reproducibility, and clinical relevance, the Thorington test is considered an appropriate and reliable variable for use in a clinical trial.

This continuous quantitative variable quantifies heterophoria in prism diopters (Δ), positive for exophoria and negative for esophoria, by neutralizing ocular recovery movement with increasing prism strength.

Normal values: ≤4Δ at distance and ≤6Δ at near (horizontal); ≤1Δ (vertical). Reliability: moderate to high (ICC 0.65-0.90), good concurrent validity with the Von Graefe test.

Continuous quantitative variable that measures the ability of the visual system to maintain binocular fusion in response to retinal disparity stimuli induced by prisms.

• Positive fusional vergence (convergence): base-out (BO) prisms.
• Negative fusional vergence (divergence): base-in (BI) prisms. Values are expressed in prism diopters (Δ), recording break and recovery points.

Normal ranges:

• Distance: convergence ≥15Δ break / ≥10Δ recovery; divergence ≥5Δ / ≥3Δ.
• Near: convergence ≥20Δ / ≥15Δ; divergence ≥12Δ / ≥7Δ. Test-retest reliability: ICC > 0.80.

Continuous quantitative variable representing the visual system's ability to maintain vertical alignment under dissociative stimuli using base-up (BU) and base-down (BD) prisms.

Normal values: break 2-3Δ, recovery ≥1.5Δ, symmetrical between eyes. Test-retest reliability: high, with strong clinical validity.

Continuous quantitative variable evaluating the efficiency of alternating between convergence and divergence. Measured in cycles per minute (cpm) using a prism combination of 3Δ base-in (BI) and 12Δ base-out (BO).

Normal values: ≥12 cpm (near vision), ≥10 cpm (distance). Test-retest reliability: ICC > 0.75; sensitive to improvements after visual therapy.

This qualitative nominal variable records the sex of each participant as registered in the electronic clinical history.

This continuous quantitative variable records age in full years, calculated from the participant's date of birth. If required for specific statistical analyses, this variable may be categorized into age ranges to explore possible differences in migraine frequency, intensity, or characteristics across age groups

This nominal qualitative variable indicates whether a family history of migraine is present (Yes/No). For positive cases, the degree of kinship of the affected relative will be specified.

This nominal qualitative variable records the type of medication taken to reduce migraine symptoms, categorized as follows:

• Analgesic (e.g., paracetamol/acetaminophen)
• Specific anti-migraine medication (triptans)
• Non-steroidal anti-inflammatory drugs (NSAIDs)
• Antiemetic
• Other medications

This continuous quantitative variable records the quantity of medication consumed during a migraine attack, expressed in milligrams (mg) or number of doses per day.

This ordinal quantitative variable records the subjective intensity of each migraine attack using a 10-point numeric rating scale, where 1 = minimal pain and 10 = maximum pain experienced.

This dichotomous qualitative variable records the presence (Yes/No) of prodromal symptoms prior to the onset of a migraine episode, as well as their type when present.

This dichotomous nominal qualitative variable records whether the participant consumed any of the following potential dietary triggers within the 24 hours prior to symptom onset: chocolate, dairy products, monosodium glutamate, caffeine, and/or histamine-rich foods.

Participants receive an informational sheet (Annex 2) describing which foods to avoid or monitor.

This continuous quantitative variable records the approximate amount of water consumed daily during participation in the study, categorized as:

• 750 mL-1 L
• 1-1.5 L
• 1.5-2 L
• 2 L per day This allows estimation of the participant's hydration level in the 24 hours preceding migraine onset.

This dichotomous quantitative variable records whether the participant consumed alcohol or other substances within the 24 hours prior to the migraine episode (Yes/No). When "Yes," the type and quantity consumed will be specified

This ordinal qualitative variable records whether the participant engaged in physical activity within the 24 hours preceding migraine onset. When physical activity is present, participants may optionally provide a brief description, including perceived intensity and activity type, to help contextualize the potential relationship with migraine triggers.

This nominal quantitative variable records whether the participant performed light, moderate, or vigorous work-related activity during the 24 hours prior to migraine onset, classified according to the World Health Organization (WHO) guidelines on physical activity intensity levels