Combined transcranial and trans-spinal direct current stimulation in chronic headache : a feasibility and safety trial for a novel intervention

Background: Chronic primary headache disorders are associated with frequent, severe pain and significant functional impairment, with treatment remaining challenging. Objective: We examined the feasibility and safety of a novel brain [transcranial direct current stimulation (tDCS)] and spinal cord stimulation [trans-spinal cord direct current stimulation (tsDCS)] treatment in chronic headache. Methods: Nine participants (3 males; aged, 40 +/- 15 years) suffering from chronic daily headache, chronic tension-type headache, or chronic migraine received the combined brain and spinal cord intervention for 5 consecutive days. Stimulation was applied for a total of 40 minutes (20 minutes of tDCS followed by 20 minutes of tsDCS) at 1 mA. Pain sensitivity and headache symptoms (frequency, severity, duration, and medications recorded via a headache diary, 4 weeks before and after treatment) were assessed. Results: The treatment was safe, feasible, and well tolerated. Headache frequency was reduced following the treatment (p = 0.026) in chronic tension-type headache and chronic migraine, but not in chronic daily headache. Headache severity was reduced immediately post-treatment in 67% of sessions. A trend towards a reduction in medication use was observed (p = 0.075). No changes in headache severity (p = 0.16) or duration (p = 0.34) were present. Conclusion: These data suggest that combined tDCS and tsDCS intervention is safe and feasible, and may improve headache frequency in patients with chronic primary headache disorders.