The safety and feasibility of transcranial direct current stimulation and exercise therapy for the treatment of cervicogenic headaches: A randomized pilot trial.

Objective: Our primary objective was to evaluate the safety and feasibility of transcranial direct current stimulation combined with exercise therapy for the treatment of cervicogenic headache. Our exploratory objectives compared symptoms of headache, mood, pain, and quality of life between active and sham transcranial direct stimulation combined with exercise therapy.

Background: Cervicogenic headache arises from injury to the cervical spine or degenerative diseases impacting cervical spine structure resulting in pain, reduced quality of life, and impaired function. Current standard-of-care treatments such as radiofrequency ablation, pharmacotherapy, manual therapy, and exercise therapy lack efficacy for some patients. Transcranial direct current stimulation is a neuromodulation technique that has shown promise in treating chronic pain conditions by positively altering neuronal activity but has not been evaluated as treatment for cervicogenic headache.

Methods: This double-blind, sham-controlled, randomized, feasibility trial recruited 32 participants between the ages of 18 and 65 years that met the International Classification of Headache Disorders third edition criteria for cervicogenic headache. Participants were randomized to receive either active or sham transcranial direct current stimulation both combined with daily exercise therapy over 6 weeks. Transcranial direct current stimulation was applied over the primary motor cortex ipsilateral to worse pain for 20 min at 2 mA with a 30 s ramp up/down period. Recruitment, retention, and adherence were evaluated for feasibility. Safety was assessed through serious and minor adverse events and an adverse effect questionnaire. Clinical outcome measures assessed headache, pain, quality of life, and mood symptoms at pre-treatment, post-treatment, and 6- and 12-weeks post-treatment.

Results: A total of 97 participants were contacted to participate with 32 recruited, 16 randomized into each group, and 14 completing the treatment protocol in both groups. Within each group 12 (active) and nine (sham) completed treatment within the proposed 6 weeks (three sessions per week), others received 18 sessions but took longer. Exercise therapy was completed on an average of 87% of days for both groups. Transcranial direct current stimulation was safe, with no serious adverse events and one minor adverse event in the active group. Itching was a more common post-intervention complaint in the active group (64% active vs. 43% sham). Exploratory analysis revealed significant group × time interactions for average headache pain from pre- to post-treatment (β = -1.012, 95% confidence interval [CI] -1.751 to -0.273; p = 0.008), 6-weeks (β = -1.370, 95% CI -2.109 to -0.631; p < 0.001), and 12-weeks (β = -1.842, 95% CI -2.600 to -1.085; p < 0.001) post-treatment, and for neck pain from pre- to post-treatment (β = -1.184, 95% CI -2.076 to -0.292; p = 0.010) and 12-weeks (β = -1.029, 95% CI -1.944 to -0.114; p = 0.028) post-treatment favoring active vs. sham. There were no significant group × time interactions for quality of life or mood.

Conclusion: The combination of transcranial direct stimulation and exercise therapy is safe and feasible for treating cervicogenic headache. While some promise has been shown for reducing headache and neck pain, larger scale trials with adequate power are needed to confirm these findings.