Background: Headache is one of the most common debilitating chronic pain conditions in patients with mild traumatic brain injury. Conventional pharmacological treatments have not been shown to be effective in alleviating debilitating mild traumatic brain injury related headaches (MTBI-HA). Therefore, the development of an innovative non-invasive therapy in managing MTBI-HA is needed in the field of pain management. Repetitive transcranial magnetic stimulation (rTMS) utilizes a basic electromagnetic coupling principle in which a rapid discharge of electrical current is converted into dynamic magnetic flux, allowing the induction of a localized current in the brain for neuromodulation. The treatment is currently FDA approved for treating depression in the United States. Recent meta-analysis studies have implicated its usage in chronic pain management.
Objective: The objective of the prospective case series is to assess the potential application of rTMS in alleviating MTBI-HA.
Study design: A prospective evaluation was conducted in patients with established diagnoses of MTBI-HA and treated with neuronavigational guided rTMS.
Setting: The study was conducted at the Veteran Administration San Diego Healthcare System where over 400 patients with MTBI were being evaluated annually by the Rehabilitation Medicine Service. A fraction of this patient population was referred and evaluated in the Anesthesia Pain Clinic for the consideration of rTMS for their headaches.
Methods: A prospective case series was conducted with human subject protection committee approval. Patients with established diagnoses of MTBI and constant headaches rated at = 4 on a 0 - 10 Numerical Rating Pain Scale (NRPS), and on stable headache medication regimens were selected to receive the treatment. Four sessions of rTMS were delivered to specific areas of cortices over a 2-month period. Patients' average intensities of lingering constant headaches (defined as duration of headache lasting more than 48 hours), and the average frequency (number of severe headache episodes per day), intensity (NRPS), and duration (hours) of headache exacerbations were assessed before and after the rTMS treatment protocol.
Results: Six men (average age of 50) with MTBI-HA received the rTMS treatment protocol. Average pre and post-rTMS constant headache scores (± SD) on the NRPS were 5.50 (± 1.38) and 2.67 (± 1.75), respectively, with an average post-rTMS headache intensity reduction of 53.05% (± 19.90). The average headache exacerbation frequency (episodes per week) was reduced by 78.97% (±19.88) with 2 patients reporting complete cessation of severe headache episodes. For those (N = 4) with persistent headache exacerbations, the average duration and intensity of these exacerbations were reduced by 50.0% and 31.7%, respectively.
Limitations: This prospective evaluation provides the initial insight that rTMS may be beneficial in alleviating a debilitating chronic pain condition in patients with MTBI-HA. More controlled randomized studies should be conducted to validate its efficacy. Other co-existing cognitive and mood dysfunction should be assessed as well.
Conclusions: rTMS offers a non-invasive treatment option for MTBI-HA. The tested treatment protocol was well tolerated by the patients and can be adopted for future randomized controlled studies in further validating the treatment efficacy.