Effect of Isometric Neck Exercises on Cervicogenic Headache Symptoms, Cortisol and BDNF Levels Among Smart Phone Users

Smartphone addiction (SPA) increasingly contributes to cervicogenic headaches (CGH) and alters stress biomarkers (cortisol, BDNF) in adolescents. This study aims to evaluate isometric neck exercises' impact on CGH symptoms, cortisol, and BDNF levels in SPA-affected adolescents. It will be a single-blind randomized controlled trial (RCT). This study had a sample size of 44, based on a medium effect size of 0.9 with 80% power. Which include adolescents (13 to 24 years) with SPA and CGH.

Intervention: One month of supervised/home-based isometric neck exercises (n=24) versus control (n=24).

Outcomes: Primary: Changes in NDI, HIT-6. Secondary: Changes in cortisol, BDNF, PSQI from baseline to 1-month.

This RCT will assess if isometric exercises reduce CGH symptoms and modulate key biomarkers such as BDNF informing interventions for SPA-related health issues.

The primary outcome for this study was the reduction in Cervicogenic Headache (CGH) symptom burden and associated pain sensitization processes involved in causing CGH. This outcome will be quantified by measuring the change from baseline to 1-month post-intervention using three distinct measures:

• The Neck Disability Index (NDI): A questionnaire assessing perceived functional disability related to neck issues.
• The Headache Impact Test (HIT-6): A questionnaire evaluating the impact of headaches on daily function.
• Serum Brain-Derived Neurotrophic Factor (BDNF) levels: Determined via ELISA analysis, utilized as a biomarker potentially reflecting changes in neuronal plasticity associated with pain sensitization.

The secondary outcome will be stress reduction, evaluated via both physiological and subjective indicators linked to stress levels. This will be quantified by measuring the change from baseline to 1-month post-intervention using:

• Serum Cortisol levels: Determined via ELISA analysis, serving as a physiological marker of hypothalamic-pituitary-adrenal (HPA) axis activity.
• The Pittsburgh Sleep Quality Index (PSQI): A questionnaire assessing subjective sleep quality, considered here as an indicator influenced by overall stress. The Intervention Group (n=22) will participate in supervised exercise sessions twice weekly at the IPMR KMU Physiotherapy Department, each lasting 30 minutes and led by a physiotherapist. These sessions will include specific exercises:

TENS (for pain relief): Intensity is typically set to a sensory level, where the patient feels a comfortable tingling or buzzing sensation without muscle contraction. Pulse duration often ranges from 50-100 microseconds, and treatment sessions usually last for 20-30 minutes, performed once or twice daily.

Chin tuck in Gently retract chin backward ("double chin") while sitting or standing tall, keeping eyes forward. Low intensity, focusing on controlled muscle activation. Aims to strengthen deep neck muscles, improve posture, and stretch sub occipital muscles. Repetitions 10 times and hold times 10 sec and then released.

Isometric exercises involve contracting neck muscles against a fixed resistance (like your hand or a wall) in various directions (flexion, extension, lateral flexion, rotation) for 10-second holds. Performed at a moderate intensity for 10 repetitions, lasting about 15 minutes, this strengthening exercise aims to build neck muscle strength and endurance.

Head protrusion in antigravity Lying down with head slightly off the edge, actively lift head to neutral or hold isometrically against gravity for 10 seconds, repeated 5 times at moderate intensity. This exercise strengthens deep neck flexors and improves postural endurance. Wall Push-Ups Standing facing a wall with hands shoulder-width apart, lean in by bending elbows, then push back. Intensity is moderate. Aims to strengthen chest, triceps, and key scapular stabilizers (serratus anterior, rhomboids, trapezius) for better shoulder posture. Reps 10 times Isometric shoulder shrugs by Standing or sitting tall, the individual actively elevates (shrugs) their shoulders straight up towards their ears, then lowers them back down by holding a weight of intensity is mild to moderate hold for 10 sec and repeat 6-10 times Weight-Bearing Shoulder Flexion: In supine position with both hands holding a stick/ weight raise arm forward and upward for 10 repetitions at moderate intensity. This functional exercise strengthens shoulder flexion and improves scapular/core stability under load, promoting integrated movement. Deep neck flexors engage to stabilize the head and neck against the shifting weight and forces during the arm movement.

PNF exercise for deep neck flexors in sitting position tuck chin towards the chest until the participant feels a mild to moderate stretch at the back of neck. The therapist will apply resistance in this position to engage participant deep neck flexors in isometric contraction against the slight resistance for 10 sec then completely relax participant neck muscles. Repeat this isometric contraction and relaxation of deep flexors 6-10 times. Participants will perform the same exercises daily at home for approximately 15 minutes. Patient education on posture and smartphone ergonomics. Adherence will be supported through app reminders and weekly phone check-ins, aiming for over 80% compliance. Where as controlled group will only receive posture advice subjective sleep quality, considered here as an indicator influenced by overall stress.

Inclusion criteria

• Adolescents aged 1 to 24 years.
• Smartphone addiction, defined as using a smartphone for ≥4 hours per day.
• A confirmed diagnosis of Cervicogenic Headache (CGH), as determined by a positive Cervical Flexion-Rotation Test (CFRT) performed by a physical therapist.

Exclusion criteria

• Diagnosis of other primary headache disorders (e.g., migraine, tension-type headache, cluster headache) or sinusitis.
• Presence of fever, cranial tumors, meningitis, or subarachnoid hemorrhage.
• Known carotid or vertebral artery dysfunction.
• Significant use of other screened devices (e.g., tablets, laptops) that would confound the primary exposure.
• History of prior neck injuries or cervical fractures.
• Any medical condition that renders the individual unfit to participate in a moderate exercise program.
• Presence of photophobia or phonophobia.
• Current drug addiction.
• Extreme, uncorrectable vision issues (Snellen chart score worse than 20/200 in either eye).