This cohort study aims to compare the efficacy of Xeomin injections for migraine management in patients with a history of Traumatic Brain Injury (TBI) versus those with a history of Anomalous Health Incidents (AHI). The study will be conducted at the National Intrepid Center of Excellence (NICOE) in Bethesda, MD. The primary objective is to determine if Xeomin injections result in different outcomes for migraine management between TBI and AHI patients. This is a combined retrospective and prospective cohort study design. Patients scheduled for Xeomin treatments will be categorized into TBI and AHI groups. For the prospective cohort, participants will complete a baseline questionnaire, receive their scheduled Xeomin treatment, and participate in follow-up interviews at 4-6 weeks and 10-12 weeks post-treatment. For the retrospective cohort, similar information will be acquired from existing records. Statistical analysis will compare migraine characteristics and treatment responses between the two groups. All data will be de-identified to protect patient privacy.

Headaches with migraine-like characteristics are a common sequelae of traumatic brain injury (TBI)¹-⁴ and Havana syndrome, otherwise known as anomalous health incidents (AHIs).⁵,⁶ In TBI patients, direct biomechanical forces lead to cellular injury and neuroinflammation, contributing to post-traumatic headaches. Specifically, the disruption of trigeminovascular pathways and the release of inflammatory mediators, such as calcitonin gene-related peptide (CGRP), are implicated in the pathophysiology of post-traumatic migraines. Furthermore, the presence of comorbid conditions, such as post-concussive syndrome, can exacerbate headache symptoms and complicate treatment strategies.⁷ Though the migraine-like headaches in patients with AHI are clinically similar to those seen in patients with mTBI, the absence of clear structural damage on conventional neuroimaging in many AHI cases raises questions about the underlying mechanisms.⁸,⁹ Theories involving unknown exposure and subsequent disruption of white matter function have been proposed. Some analyses suggest that the symptoms of AHI could result from the disruption of neuroimmune and neurotransmission mechanisms similar to those affected in patients with TBI.¹⁰,¹¹

Managing post-traumatic headaches involves a multidisciplinary approach including behavioral therapy, physical therapy, oral medications, injectable medications, and interventional procedures. Essentially, these headaches can be treated similarly to the primary headache disorder they resemble.¹² Thus, the post-traumatic migraine can be treated in the acute setting with triptans, NSAIDs, ergot alkaloids, antiemetics, and other therapeutics.¹³,¹⁴ For chronic management, options include beta-blockers, tricyclic antidepressants, CGRP-targeting agents, anti-seizure medications, and many other medications.¹²,¹⁵ Onabotulinum toxin A (OBA) and other medications in the class of botulinum toxins have been particularly effective at reducing the overall frequency and duration of migraines in patients with TBIs,¹⁶,¹⁷ as well as non-TBI-related migraines. OBA results in a blockade of neural stimulation by inhibiting the release of neurotransmitters at the presynaptic terminal.¹⁸,¹⁹ It's thought to reduce the exocytosis of pain mediators (substance P, CGRP) from sensory neurons by cleaving SNAP25.²⁰,²¹ This effect is temporary due to the formation of new synapses, thus patients have to return for repeat injections every 10-12 weeks. Additionally, the number of units of OBA can be optimized to the patient's level of pain during each treatment.

There is limited literature on managing post-AHI headache disorders, but recent experience indicates that using multidisciplinary approaches similar to those used for TBI-related headache disorders may be appropriate.⁶ OBA, and more specifically incobotulinum toxin A (Xeomin brand) has therefore been a commonly used treatment modality in these patient populations in the Military Health System. Many individuals with AHIs from other branches of the government are treated in the MHS though the Secretarial Designee program.

While AHI symptoms might share pathophysiological characteristics with TBIs, there's limited research on Xeomin injections' characteristics in TBI vs. AHI patients, such as treatment frequency and efficacy. This study aims to quantify these similarities and differences in migraine management with Xeomin, potentially improving our understanding of this treatment modality. Migraines can disrupt home, work, and social activities, and treatment can be especially difficult in AHI patients who face limited effective treatment options that are evidence-based, and unique diagnostic challenges. By comparing Xeomin's efficacy in both groups, this study could reveal crucial differences in treatment response, leading to more personalized and effective therapies that align with a holistic healthcare model in medicine. The findings could inform clinical guidelines and improve migraine management in TBI and AHI patients, ultimately reducing the healthcare burden. This research is essential for addressing AHI patients' unmet needs and advancing migraine treatment understanding.

Inclusion Criteria:

• At least 18 years of age
• Able to provide written consent in English
• An employee of the US Government, or an adult family member of a US Government employee
• Have received Xeomin treatment to prevent migraine related to TBI or AHI at a Military Treatment Facility or other US Medical Facility
• Able to participate in at least 80% of the assessments
• A US Citizen and not a dual national of the country where you are currently located

Exclusion Criteria:

• Prisoner
• Decisionally impaired and unable to provide informed consent
• Non-US citizen

Employees of the US Government, or adult family members of US Government employees, receiving Xeomin treatment for migraine headache following either TBI or AHI.

The study protocol specifies that there are no data sharing or data use agreements in place for this research. The data collected is intended for internal analysis by authorized research personnel only. While de-identified, aggregate results may be published, the consent form assures participants that their individual data will not be shared in any way that would identify them.